0000950170-23-036158 | 10-Q | XBRL Viewer

Allowance for Doubtful Accounts Included in Accounts Receivable Net (Detail) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Allowance for Doubtful Accounts Included in Accounts Receivable Net Detail [Abstract]
Allowance for Doubtful Accounts	$ 2.2	$ 2.6	$ 2.7

Common Stock and Preferred Stock

6 Months Ended

Jun. 30, 2023

Equity [Abstract]

Common Stock and Preferred Stock

Note 5 – Common Stock and preferred stock

Common Stock

The Company’s common stock trades on the New York Stock Exchange under the symbol, “UTL.”

The Company had 16,091,419, 16,034,635 and 16,043,355 shares of common stock outstanding at June 30, 2023, June 30, 2022 and December 31, 2022, respectively.

Dividend Reinvestment and Stock Purchase Plan - During the first six months of 2023, the Company sold 10,524 shares of its common stock, at an average price of $54.61 per share, in connection with its Dividend Reinvestment and Stock Purchase Plan (DRP) and its 401(k) plans resulting in net proceeds of approximately $574,700. The DRP provides participants in the plan a method for investing cash dividends on the Company’s common stock and cash payments in additional shares of the Company’s common stock.

Stock Plan - The Company maintains the Unitil Corporation Second Amended and Restated 2003 Stock Plan (the Stock Plan). Participants in the Stock Plan are selected by the Compensation Committee of the Board of Directors to receive awards under the Stock Plan, including: (i) awards of restricted shares that vest based on time (Time Restricted Shares); (ii) awards of restricted shares that vest based on performance (Performance Restricted Shares), effective January 24, 2023; or (iii) awards of restricted stock units (Restricted Stock Units). The Compensation Committee has the authority to determine the sizes of awards; determine the terms and conditions of awards in a manner consistent with the Stock Plan; construe and interpret the Stock Plan and any agreement or instrument entered into under the Stock Plan as they apply to participants; establish, amend, or waive rules and regulations for the Stock Plan’s administration as they apply to participants; and, subject to the provisions of the Stock Plan, amend the terms and conditions of any outstanding award to the extent such terms and conditions are within the discretion of the Compensation Committee as provided for in the Stock Plan. On April 19, 2012, the Company’s shareholders approved an amendment to the Stock Plan to, among other things, increase the maximum number of shares of common stock available for awards to plan participants.

The maximum number of shares available for awards to participants under the Stock Plan is 677,500. The maximum number of shares that may be awarded in any one calendar year to any one participant is 20,000. In the event of certain changes in capitalization of the Company, the Compensation Committee is authorized to make an equitable adjustment to the number and kind of shares of common stock that may be delivered under the Stock Plan and, in addition, may authorize and make an equitable adjustment to the Stock Plan’s annual individual award limit.

Time Restricted Shares

Outstanding awards of Time Restricted Shares fully vest over a period of four years at a rate of 25% each year. During the vesting period, dividends on Time Restricted Shares underlying the award may be credited to a participant’s account. The Company may deduct or withhold, or require a participant to remit to the Company, an amount sufficient to satisfy any taxes required by federal, state, or local law or regulation to be withheld with respect to any taxable event arising in connection with an award.

Prior to the end of the vesting period, the Time Restricted Shares are subject to forfeiture if the participant ceases to be employed by the Company other than due to the participant’s death, disability or retirement.

On January 24, 2023, 18,770 Time Restricted Shares were issued in conjunction with the Stock Plan with an aggregate market value at the date of issuance of approximately $1.0 million. There were 64,243 and 73,178 non-vested Time Restricted Shares under the Stock Plan as of June 30, 2023 and 2022, respectively. The weighted average grant date fair value of these shares was $48.02 and $47.44 per share, respectively. The compensation expense associated with the issuance of Time Restricted Shares under the Stock Plan is being recognized over the vesting period and was $1.3 million and $1.8 million for the six months ended June 30, 2023 and 2022, respectively. At June 30, 2023, there was approximately $0.9 million of total unrecognized compensation cost for Time Restricted Shares under the Stock Plan which is expected to be recognized over approximately 2.6 years. During the six months ended June 30, 2023, there were zero Time Restricted Shares forfeited and zero Time Restricted Shares cancelled under the Stock Plan.

Performance Restricted Shares

Outstanding awards of Performance Restricted Shares vest after a performance period of three years based on the attainment of certain goals set by the Compensation Committee at the beginning of the performance period. If goals are met, awards of Performance Restricted Shares may vest fully; if goals are exceeded, awards of Performance Restricted Shares may vest fully and additional shares of common stock may be awarded; if goals are not met, a portion of the Performance Restricted Shares may vest and/or all or a portion of the Performance Restricted Shares may be forfeited. During the performance period, dividends on Performance Restricted Shares underlying the award may be credited to a participant’s account. The Company may deduct or withhold, or require a participant to remit to the Company, an amount sufficient to satisfy any taxes required by federal, state, or local law or regulation to be withheld with respect to any taxable event arising in connection with an award.

Prior to the end of the performance period, the Performance Restricted Shares are subject to forfeiture if the participant ceases to be employed by the Company other than due to the participant’s death, disability or retirement. Initial awards of Performance Restricted Shares were granted January 24, 2023. No Performance Restricted Shares were awarded in 2022. On January 24, 2023, there were 18,770 Performance Restricted Shares issued under the Stock Plan with an aggregate market value of $1.0 million. There were 18,770 non-vested Performance Restricted Shares under the Stock Plan as of June 30, 2023. The weighted average grant date fair value of these shares was $51.83 per share. The compensation expense associated with the issuance of Performance Restricted Shares under the Stock Plan is being recognized over the vesting period and was $0.2 million for the six months ended June 30, 2023. At June 30, 2023, there was approximately $1.0 million of total unrecognized compensation cost for Performance Restricted Shares under the Stock Plan which is expected to be recognized over approximately 2.5 years. During the six months ended June 30, 2023 there were zero

Performance Restricted Shares forfeited and zero Performance Restricted Shares cancelled under the Stock Plan.

Restricted Stock Units

Non-management members of the Company’s Board of Directors (Directors) may elect to receive the equity portion of their annual retainer in the form of Restricted Stock Units (RSU). Restricted Stock Units earn dividend equivalents and will generally be settled by payment to each Director as soon as practicable following the Director’s separation from service to the Company. The Restricted Stock Units will be paid such that the Director will receive (i) 70% of the shares of the Company’s common stock underlying the restricted stock units and (ii) cash in an amount equal to the fair market value of 30% of the shares of the Company’s common stock underlying the Restricted Stock Units. The equity portion of Restricted Stock Units activity during the six months ended June 30, 2023 in conjunction with the Stock Plan is presented in the following table:


Restricted Stock Units (Equity Portion)
	Units		Weighted Average Stock Price
Restricted Stock Units as of December 31, 2022		43,799	$	40.17
Restricted Stock Units Granted		—	$	—
Dividend Equivalents Earned		669	$	53.24
Restricted Stock Units Settled		—	$	—
Restricted Stock Units as of June 30, 2023		44,468	$	40.37

There were 39,595 Restricted Stock Units outstanding as of June 30, 2022 with a weighted average stock price of $39.37. Included in Other Noncurrent Liabilities on the Company’s Consolidated Balance Sheets as of June 30, 2023, June 30, 2022 and December 31, 2022 is $1.0 million, $1.0 million and $1.0 million, respectively, representing the fair value of liabilities associated with the portion of fully vested RSUs that will be settled in cash.

Preferred Stock

There were $0.2 million, or 1,727 shares, of Unitil Energy’s 6.00% Series Preferred Stock outstanding as of June 30, 2023. There were $0.2 million, or 1,861 shares, Unitil Energy’s 6.00% Series Preferred Stock outstanding as of June 30, 2022 and December 31, 2022. There were less than $0.1 million of total dividends declared on Preferred Stock in each of the three month periods ended June 30, 2023 and June 30, 2022, respectively.

- Definition

The entire disclosure for equity.

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+ Details

Consolidated Statements Of Changes In Common Stock Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Equity [Abstract]
Dividends per Common Share	$ 0.405	$ 0.39	$ 0.81	$ 0.78
Common stock, shares issued	5,189	4,352	10,524	9,863

Key Weighted Average Assumptions Used in Determining Benefit Plan Costs and Obligations (Detail) - Benefit Plan Costs [Member]	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	5.25%	2.85%
Rate of Compensation Increase	3.00%	3.00%
Expected Long-term rate of return on plan assets	7.50%	7.50%

Debt and Financing Arrangements - Details on Long Term Debt (Parenthetical) (Detail)	6 Months Ended
	Jun. 30, 2023
3.70% Senior Notes, Due August 1, 2026
Debt Instrument [Line Items]
Stated interest rate	3.70%
Debt instrument due date	Aug. 01, 2026
3.43% Senior Notes, Due December 18, 2029
Debt Instrument [Line Items]
Stated interest rate	3.43%
Debt instrument due date	Dec. 18, 2029
First Mortgage Bonds 8.49% Senior Secured Notes, Due October 14, 2024 \| Unitil Energy Systems Inc [Member]
Debt Instrument [Line Items]
Stated interest rate	8.49%
Debt instrument due date	Oct. 14, 2024
First Mortgage Bonds 6.96% Senior Secured Notes, Due September 1, 2028 \| Unitil Energy Systems Inc [Member]
Debt Instrument [Line Items]
Stated interest rate	6.96%
Debt instrument due date	Sep. 01, 2028
First Mortgage Bonds 8.00% Senior Secured Notes, Due May 1, 2031 \| Unitil Energy Systems Inc [Member]
Debt Instrument [Line Items]
Stated interest rate	8.00%
Debt instrument due date	May 01, 2031
First Mortgage Bonds 6.32% Senior Secured Notes, Due September 15, 2036 \| Unitil Energy Systems Inc [Member]
Debt Instrument [Line Items]
Stated interest rate	6.32%
Debt instrument due date	Sep. 15, 2036
3.58% Senior Secured Notes, Due September 15, 2040 \| Unitil Energy Systems Inc [Member]
Debt Instrument [Line Items]
Stated interest rate	3.58%
Debt instrument due date	Sep. 15, 2040
First Mortgage Bonds 4.18% Senior Secured Notes Due November 30, 2048 \| Unitil Energy Systems Inc [Member]
Debt Instrument [Line Items]
Stated interest rate	4.18%
Debt instrument due date	Nov. 30, 2048
6.79% Senior Notes, Due October 15, 2025 \| Fitchburg Gas And Electric Light Company [Member]
Debt Instrument [Line Items]
Stated interest rate	6.79%
Debt instrument due date	Oct. 15, 2025
3.52% Senior Notes, Due November 1, 2027 \| Fitchburg Gas And Electric Light Company [Member]
Debt Instrument [Line Items]
Stated interest rate	3.52%
Debt instrument due date	Nov. 01, 2027
3.52% Senior Notes, Due November 1, 2027 \| Northern Utilities Inc [Member]
Debt Instrument [Line Items]
Stated interest rate	3.52%
Debt instrument due date	Nov. 01, 2027
7.37% Notes, Due January 15, 2029 \| Fitchburg Gas And Electric Light Company [Member]
Debt Instrument [Line Items]
Stated interest rate	7.37%
Debt instrument due date	Jan. 15, 2029
5.90% Notes, Due December 15, 2030 \| Fitchburg Gas And Electric Light Company [Member]
Debt Instrument [Line Items]
Stated interest rate	5.90%
Debt instrument due date	Dec. 15, 2030
7.98% Notes, Due June 1, 2031 \| Fitchburg Gas And Electric Light Company [Member]
Debt Instrument [Line Items]
Stated interest rate	7.98%
Debt instrument due date	Jun. 01, 2031
3.78% Senior Notes, Due September 15, 2040 \| Fitchburg Gas And Electric Light Company [Member]
Debt Instrument [Line Items]
Stated interest rate	3.78%
Debt instrument due date	Sep. 15, 2040
3.78% Senior Notes, Due September 15, 2040 \| Northern Utilities Inc [Member]
Debt Instrument [Line Items]
Stated interest rate	3.78%
Debt instrument due date	Sep. 15, 2040
4.32% Senior Notes, Due November 1, 2047 \| Fitchburg Gas And Electric Light Company [Member]
Debt Instrument [Line Items]
Stated interest rate	4.32%
Debt instrument due date	Nov. 01, 2047
4.32% Senior Notes, Due November 1, 2047 \| Northern Utilities Inc [Member]
Debt Instrument [Line Items]
Stated interest rate	4.32%
Debt instrument due date	Nov. 01, 2047
7.72% Senior Notes, Due December 3, 2038 \| Northern Utilities Inc [Member]
Debt Instrument [Line Items]
Stated interest rate	7.72%
Debt instrument due date	Dec. 03, 2038
4.42% Senior Notes, Due October 15, 2044 \| Northern Utilities Inc [Member]
Debt Instrument [Line Items]
Stated interest rate	4.42%
Debt instrument due date	Oct. 15, 2044
4.04% Senior Notes, Due September 12, 2049 \| Northern Utilities Inc [Member]
Debt Instrument [Line Items]
Stated interest rate	4.04%
Debt instrument due date	Sep. 12, 2049
3.72% Senior Notes, Due November 1, 2027 \| Granite State Gas Transmission Inc [Member]
Debt Instrument [Line Items]
Stated interest rate	3.72%
Debt instrument due date	Nov. 01, 2027
2.64% Senior Secured Notes, Due December 18, 2030 \| Unitil Realty Corp Member
Debt Instrument [Line Items]
Stated interest rate	2.64%
Debt instrument due date	Dec. 18, 2030

Components of Accrued Revenue (Detail) - USD ($)
$ in Millions

Jun. 30, 2023

Dec. 31, 2022

Jun. 30, 2022

Deferred Revenue Arrangement [Line Items]

Regulatory Asset, Current

^[1]

$ 56.8

$ 66.5

$ 41.4

Total Accrued Revenue

60.4

72.8

45.6

Regulatory Assets

Deferred Revenue Arrangement [Line Items]

Regulatory Asset, Current

56.8

66.5

41.4

Unbilled Revenues

Deferred Revenue Arrangement [Line Items]

Regulatory Asset, Current

$ 3.6

$ 6.3

$ 4.2

[1]	Reflects amounts included in the Accrued Revenue on the Company’s Consolidated Balance Sheets.

Fair Value of Marketable Securities (Detail) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	$ 5.8	$ 5.8	$ 5.4
Deferred Compensation Plan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	1.1	0.6	0.8
Fair Value, Inputs, Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	5.8	5.8	5.4
Fair Value, Inputs, Level 1 \| Deferred Compensation Plan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	1.1	0.6	0.8
Fair Value, Inputs, Level 1 \| Equity Funds \| Deferred Compensation Plan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	1.0	0.5	0.4
Fair Value, Inputs, Level 1 \| Money Market Funds
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	5.8	5.8	5.4
Fair Value, Inputs, Level 1 \| Money Market Funds \| Deferred Compensation Plan [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Trading Securities	$ 0.1	$ 0.1	$ 0.4

Environmental Matters

6 Months Ended

Jun. 30, 2023

Text Block [Abstract]

Environmental Matters

note 7 – eNVIRONMENTAL MATTERS

Unitil’s Environmental matters are described in Note 8 to the Financial Statements in Item 8 of Part II of Unitil Corporation’s Form 10-K for December 31, 2022 as filed with the Securities and Exchange Commission on february 14, 2023.

The Company’s past and present operations include activities that are generally subject to extensive and complex federal and state environmental laws and regulations. The Company is in material compliance with applicable environmental and safety laws and regulations and, as of June 30, 2023, has not identified any material losses reasonably likely to be incurred in excess of recorded amounts. However, the Company cannot assure that significant costs and liabilities will not be incurred in the future. It is possible that other developments, such as increasingly stringent federal, state or local environmental laws and regulations could result in increased environmental compliance costs. Based on its current assessment of its environmental responsibilities, existing legal requirements and regulatory policies, the Company does not believe that these environmental costs will have a material adverse effect on the Company’s consolidated financial position or results of operations.

Northern Utilities Manufactured Gas Plant Sites - Northern Utilities has an extensive program to identify, investigate and remediate former manufactured gas plant (MGP) sites, which were operated from the mid-1800s through the mid-1900s. In New Hampshire, MGP sites were identified in Dover, Exeter, Portsmouth, Rochester and Somersworth. In Maine, Northern Utilities has documented the presence of MGP sites in Lewiston and Portland, and a former MGP disposal site in Scarborough.

Northern Utilities has worked with the Maine Department of Environmental Protection and New Hampshire Department of Environmental Services (NH DES) to address environmental concerns with these sites. Northern Utilities or others have completed remediation activities at all sites; however, on site monitoring continues at several sites which may result in future remedial actions as directed by the applicable regulatory agency.

In July 2019, the NH DES requested that Northern Utilities review modeled expectations for groundwater contaminants against observed data at the Rochester site. In June 2020, the NH DES coupled the submittal of the review to a proposed extension of the gas distribution system by Northern Utilities. Northern Utilities submitted the review in January 2022, and the NH DES directed that soil treatability studies as part of a Remedial Action Plan (RAP) be developed in June 2022. The Company submitted the studies and RAP to the NH DES in December 2022 and continues to await a decision from the agency; the RAP included three remediation alternatives for consideration by NH DES. In anticipation of the probable NH DES approval of one of the remediation alternatives and subsequent request for project design, the Company has accrued $2.5 million for estimated costs to complete the remediation at the Rochester site, which is included in Environmental Obligations. The Company has determined that the high end of the range of reasonably possible remediation costs for the Rochester site could be $5.6 million based on remediation alternatives. Northern Utilities anticipates the commencement of remediation activities in 2024.

The NHPUC and MPUC have approved regulatory mechanisms for the recovery of MGP environmental costs. For Northern Utilities’ New Hampshire division, the NHPUC has approved the recovery of MGP environmental costs over succeeding seven-year periods. For Northern Utilities’ Maine division, the MPUC has authorized the recovery of environmental remediation costs over succeeding five-year periods.

The Environmental Obligations table includes amounts accrued for Northern Utilities related to estimated future cleanup costs associated with Northern Utilities’ environmental remediation obligations for former MGP sites. Corresponding Regulatory Assets were recorded to reflect that the future recovery of these environmental remediation costs is expected based on regulatory precedent and established practices.

Fitchburg’s Manufactured Gas Plant Site - Fitchburg has worked with the Massachusetts Department of Environmental Protection (Mass DEP) to address environmental concerns with the former MGP site at Sawyer Passway, and has substantially completed remediation activities, though on site monitoring continues. In April 2020, Fitchburg received notification from the Massachusetts Department of Transportation (Mass DOT) that a portion of the site may be incorporated into the proposed Twin City Rail Trail with an anticipated commencement date in 2025. Depending upon the final agreement between Fitchburg and Mass DOT, additional minor costs are expected prior to completion.

In August 2021, the Mass DEP issued a Notice of Non-compliance to Fitchburg following a November 2020 audit of the September 2015 Response Action Outcome on the MGP site. Mass DEP directed Fitchburg to further define the extent of MGP site contaminants in the sediment and riverbank of an abutting watercourse. Fitchburg began the investigation in November 2021 with the Mass DEP expanding the scope in June 2022 to include an observed river seep. Fitchburg submitted the results of its investigation and an Immediate Response Action (IRA) plan associated with the river seep to the Mass DEP in December 2022. The Mass DEP has review and approval authority over the IRA plan’s recommendations, and Fitchburg continues to anticipate a limited remediation effort associated with the seep in 2023. In June 2023, the IRA plan transitioned to a Mass DEP-required public risk characterization of the

site. The Company does not believe this risk characterization will have a material adverse effect on its financial condition, results of operations or cash flows.

Fitchburg recovers the environmental response costs incurred at this former MGP site in gas rates pursuant to the terms of a cost recovery agreement approved by the MDPU. Pursuant to this agreement, Fitchburg is authorized to amortize and recover environmental response costs from gas customers over succeeding seven-year periods.

Unitil Energy - Kensington Distribution Operations Center - Unitil Energy conducted a Phase I and II environmental site assessment (ESA) in the second quarter of 2021. The ESA results identified soil and groundwater contaminants in excess of state regulatory standards. In September 2021, the NH DES directed Unitil Energy to conduct a supplemental site investigation (SSI) and identify whether there is a need to conduct further investigation or remedial actions. Unitil Energy began the SSI in December 2021 with the NH DES extending the SSI scope in June 2022 to further delineate potential impacts. Unitil Energy completed the field portion of the SSI in September 2022 and submitted the report to the NH DES in June 2023 and is awaiting a decision by the agency. Unitil Energy anticipates the commencement of remediation activities in 2025. The Company does not believe this investigation will have a material adverse effect on its financial condition, results of operations or cash flows.

The following table sets forth a summary of changes in the Company’s liability for Environmental Obligations for the six months ended June 30, 2023 and 2022.


Environmental Obligations (millions)
	June 30,
	2023		2022
Total Balance at Beginning of Period	$	4.4	$	2.7
Additions		0.5		0.3
Less: Payments / Reductions		0.2		0.2
Total Balance at End of Period		4.7		2.8
Less: Current Portion		0.6		0.6
Noncurrent Balance at End of Period	$	4.1	$	2.2

- Definition

The entire disclosure for environmental loss contingencies, such as presence of hazardous waste, relevant information from reports issued by regulators, and estimated costs to achieve compliance with regulatory requirements. This element may be used for all of an entity's disclosures about environmental loss contingencies.

+ References

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+ Details

Components of Retirement Plan Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost	$ 523	$ 791	$ 1,046	$ 1,582
Interest Cost	1,870	1,371	3,740	2,742
Expected Return on Plan Assets	(2,672)	(2,720)	(5,344)	(5,440)
Prior Service Cost Amortization	88	89	177	178
Actuarial Loss Amortization		1,377		2,754
Sub-total	(191)	908	(381)	1,816
Amounts Capitalized and Deferred	366	(309)	864	(464)
Net Periodic Benefit Cost Recognized	175	599	483	1,352
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost	373	722	746	1,444
Interest Cost	725	799	1,450	1,598
Expected Return on Plan Assets	(852)	(854)	(1,704)	(1,708)
Prior Service Cost Amortization	199	273	397	546
Actuarial Loss Amortization	(366)	255	(732)	510
Sub-total	79	1,195	157	2,390
Amounts Capitalized and Deferred	112	(622)	333	(1,133)
Net Periodic Benefit Cost Recognized	191	573	490	1,257
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost	63	68	125	136
Interest Cost	188	118	377	236
Prior Service Cost Amortization	14	14	28	28
Actuarial Loss Amortization		199		399
Sub-total	265	399	530	799
Amounts Capitalized and Deferred	(82)	(119)	(164)	(238)
Net Periodic Benefit Cost Recognized	$ 183	$ 280	$ 366	$ 561

Segment Information (Tables)

6 Months Ended

Jun. 30, 2023

Significant Segment Financial Data

The following table provides significant segment financial data for the three and six months ended June 30, 2023 and June 30, 2022.


	Electric			Gas			Other			Total
Three Months Ended June 30, 2023 (millions)
Revenues:
Billed and Unbilled Revenue	$	69.8		$	45.3		$	—		$	115.1
Rate Adjustment Mechanism Revenue		(5.3	)		(6.4	)		—			(11.7	)
Total Operating Revenues		64.5			38.9			—			103.4
Segment Profit (Loss)		3.6			0.9			(0.3	)		4.2
Capital Expenditures		13.4			22.0			—			35.4

Three Months Ended June 30, 2022 (millions)
Revenues:
Billed and Unbilled Revenue	$	64.1		$	49.6		$	—		$	113.7
Rate Adjustment Mechanism Revenue		(9.8	)		(5.0	)		—			(14.8	)
Total Operating Revenues		54.3			44.6			—			98.9
Segment Profit (Loss)		3.9			1.3			(0.3	)		4.9
Capital Expenditures		7.9			22.0			—			29.9

Six Months Ended June 30, 2023 (millions)
Revenues:
Billed and Unbilled Revenue	$	167.4		$	167.2		$	—		$	334.6
Rate Adjustment Mechanism Revenue		5.3			(16.3	)		—			(11.0	)
Total Operating Revenues		172.7			150.9			—			323.6
Segment Profit (Loss)		8.9			19.9			(0.5	)		28.3
Capital Expenditures		24.0			33.5			0.1			57.6
Segment Assets		610.5			961.9			22.9			1,595.3

Six Months Ended June 30, 2022 (millions)
Revenues:
Billed and Unbilled Revenue	$	148.8		$	163.3		$	—		$	312.1
Rate Adjustment Mechanism Revenue		(5.3	)		(15.3	)		—			(20.6	)
Total Operating Revenues		143.5			148.0			—			291.5
Segment Profit (Loss)		7.3			19.8			(0.7	)		26.4
Capital Expenditures		14.2			31.0			0.1			45.3
Segment Assets		593.0			936.0			18.1			1,547.1

Dividends Declared Per Share

6 Months Ended

Jun. 30, 2023

DIVIDENDS DECLARED PER SHARE [Abstract]

Dividends Declared Per Share

Note 2 - Dividends Declared Per Share


Declaration Date	Date Paid (Payable)	Shareholder of Record Date	Dividend Amount
07/26/23	08/28/23	08/14/23	$	0.405
04/26/23	05/30/23	05/15/23	$	0.405
01/25/23	02/28/23	02/14/23	$	0.405
10/26/22	11/28/22	11/14/22	$	0.390
07/27/22	08/26/22	08/12/22	$	0.390
04/27/22	05/27/22	05/13/22	$	0.390
01/26/22	02/25/22	02/11/22	$	0.390

Restricted Stock Units Issued (Detail) - Restricted Stock Units (RSUs)	6 Months Ended
	Jun. 30, 2023 $ / shares shares
Restricted Stock Units
Beginning Restricted Stock Units \| shares	43,799
Restricted Stock Units Granted \| shares	0
Dividend Equivalents Earned \| shares	669
Restricted Stock Units Settled \| shares	0
Ending Restricted Stock Units \| shares	44,468
Weighted-Average Stock Price
Beginning Restricted Stock Units \| $ / shares	$ 40.17
Restricted Stock Units Granted \| $ / shares	0
Dividend Equivalents Earned \| $ / shares	53.24
Restricted Stock Units Settled \| $ / shares	0
Ending Restricted Stock Units \| $ / shares	$ 40.37

Debt and Financing Arrangements - Classification of the Company Lease Obligations (Detail) - USD ($) $ in Millions	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022
Operating Lease Obligations:
Other Current Liabilities (current portion)	$ 1.7	$ 1.7	$ 1.5	$ 1.5
Other Noncurrent Liabilities (long-term portion)	3.5	3.5	2.8	2.9
Total Operating Lease Obligations	5.2		4.3	4.4
Capital Lease Obligations:
Other Current Liabilities (current portion)	0.1	0.1	0.1	0.1
Other Noncurrent Liabilities (long-term portion)	0.3	$ 0.3	0.1	0.1
Total Capital Lease Obligations	0.4		0.2	0.2
Total Lease Obligations	5.6		$ 4.5	$ 4.6
Lease Obligations [Member]
Operating Lease Obligations:
Total Operating Lease Obligations	$ 5,247.0

Summary of Significant Accounting Policies

6 Months Ended

Jun. 30, 2023

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Note 1 - Summary of Significant Accounting Policies

Nature of Operations - Unitil Corporation (Unitil or the Company) is a public utility holding company. Unitil and its subsidiaries are subject to regulation as a holding company system by the Federal Energy Regulatory Commission (FERC) under the Energy Policy Act of 2005. The following companies are wholly-owned subsidiaries of Unitil: Unitil Energy Systems, Inc. (Unitil Energy), Fitchburg Gas and Electric Light Company (Fitchburg), Northern Utilities, Inc. (Northern Utilities), Granite State Gas Transmission, Inc. (Granite State), Unitil Power Corp. (Unitil Power), Unitil Realty Corp. (Unitil Realty), Unitil Service Corp. (Unitil Service) and its non-regulated business unit Unitil Resources, Inc. (Unitil Resources).

The Company’s earnings historically have been seasonal and typically higher in the first and fourth quarters when customers use gas for heating purposes.

Unitil’s principal business is the local distribution of electricity in the southeastern seacoast and capital city areas of New Hampshire and the greater Fitchburg area of north central Massachusetts and the local distribution of gas in southeastern New Hampshire, portions of southern Maine to the Lewiston-Auburn area and in the greater Fitchburg area of north central Massachusetts. Unitil has three distribution utility subsidiaries, including Unitil Energy, which operates in New Hampshire; Fitchburg, which operates in Massachusetts; and Northern Utilities, which operates in New Hampshire and Maine (collectively referred to as the “distribution utilities”).

Granite State is an interstate gas transmission pipeline company, operating 86 miles of underground gas transmission pipeline primarily located in Maine and New Hampshire. Granite State provides Northern Utilities with interconnection to three major gas pipelines and access to domestic gas supplies in the south and Canadian gas supplies in the north. Granite State derives its revenues principally from transportation services provided to Northern Utilities and, to a lesser extent, third-party marketers.

A fifth utility subsidiary, Unitil Power, formerly functioned as the full requirements wholesale power supply provider for Unitil Energy. In connection with the implementation of electric industry restructuring in New Hampshire, on May 1, 2003 Unitil Power ceased being the wholesale supplier of Unitil Energy and divested of its long-term power supply contracts through the sale of the entitlements to the electricity associated with various electric power supply contracts it had acquired to serve Unitil Energy’s customers. In the period since, Unitil Power continued to flow revenues and expenses from remaining contracts to Unitil Energy under the Amended Unitil System Agreement. The last of those contracts expired October 31, 2020, and the Company no longer has material revenues or expenses associated with them.

Unitil also has three other wholly-owned subsidiaries: Unitil Service, Unitil Realty and Unitil Resources. Unitil Service provides, at cost, a variety of administrative and professional services, including regulatory, financial, accounting, human resources, engineering, operations, technology, energy management and management services on a centralized basis to its affiliated Unitil companies. Unitil Realty owns and manages the Company’s corporate office in Hampton, New Hampshire and leases this facility to Unitil Service under a long-term lease arrangement. Unitil Resources is the Company’s wholly-owned non-regulated subsidiary.

Basis of Presentation - The accompanying unaudited consolidated financial statements of Unitil have been prepared in accordance with the instructions to Form 10-Q and include the information and footnotes required by generally accepted accounting principles. In the opinion of management, all adjustments considered necessary for a fair presentation have been included. The results of operations for the three and six months ended June 30, 2023 are not necessarily indicative of results to be expected for the year ending December 31, 2023. For additional information, refer to Note 1 of Part II to the Consolidated Financial Statements – “Summary of Significant Accounting Policies” of the Company’s Form 10-K for the year ended December 31, 2022, as filed with the Securities and Exchange Commission (SEC) on February 14, 2023, for a description of the Company’s Basis of Presentation.

Utility Revenue Recognition - Electric Operating Revenues and Gas Operating Revenues consist of billed and unbilled revenue and revenue from rate adjustment mechanisms. Billed and unbilled revenue includes delivery revenue and pass-through revenue, recognized according to tariffs approved by federal and state regulatory commissions, which determine the amount of revenue the Company will record for these items. Revenue from rate adjustment mechanisms is accrued revenue, recognized in connection with rate adjustment mechanisms, and authorized by regulators for recognition in the current period for future cash recoveries from, or credits to, customers.

Revenue is recorded when service is rendered or energy is delivered to customers. However, the determination of energy sales to individual customers is based on the reading of their meters, which occurs on a systematic basis throughout the month. At the end of each calendar month, amounts of energy delivered to customers since the date of the last meter reading are estimated and the corresponding unbilled revenues are calculated. These unbilled revenues are estimated each month based on estimated customer usage by class and applicable customer rates, taking into account current and historical weather data, assumptions pertaining to metering patterns, billing cycle statistics, and other estimates and assumptions, and are then reversed in the following month when billed to customers.

A majority of the Company’s revenue from contracts with customers continues to be recognized on a monthly basis based on applicable tariffs and customer monthly consumption. Such revenue is recognized using the invoice practical expedient, which allows an entity to recognize revenue in the amount that directly corresponds to the value transferred to the customer.

The Company’s billed and unbilled revenue meets the definition of “revenues from contracts with customers” as defined in Accounting Standards Codification (ASC) 606. Revenue recognized in connection with rate adjustment mechanisms is consistent with the definition of alternative revenue programs in ASC 980-605-25-3, as the Company has the ability to adjust rates in the future as a result of past activities or completed events. The rate adjustment mechanisms meet the criteria within ASC 980-605-25-4. In cases where allowable costs are greater than operating revenues billed in the current period for the individual rate adjustment mechanism, additional operating revenue is recognized. In cases where allowable costs are less than operating revenues billed in the current period for the individual rate adjustment mechanism, operating revenue is reduced. ASC 606 requires the Company to disclose separately the amount of revenues from contracts with customers and alternative revenue program revenues.

In the following tables, revenue is classified by the types of goods/services rendered and market/customer type.


	Three Months Ended June 30, 2023
Electric and Gas Operating Revenues (millions):	Electric			Gas			Total
Billed and Unbilled Revenue:
Residential	$	39.8		$	17.9		$	57.7
Commercial and Industrial		28.1			26.4			54.5
Other		1.9			1.0			2.9
Total Billed and Unbilled Revenue		69.8			45.3			115.1
Rate Adjustment Mechanism Revenue		(5.3	)		(6.4	)		(11.7	)
Total Electric and Gas Operating Revenues	$	64.5		$	38.9		$	103.4


	Three Months Ended June 30, 2022
Electric and Gas Operating Revenues (millions):	Electric			Gas			Total
Billed and Unbilled Revenue:
Residential	$	33.8		$	18.1		$	51.9
Commercial and Industrial		25.7			28.0			53.7
Other		4.6			3.5			8.1
Total Billed and Unbilled Revenue		64.1			49.6			113.7
Rate Adjustment Mechanism Revenue		(9.8	)		(5.0	)		(14.8	)
Total Electric and Gas Operating Revenues	$	54.3		$	44.6		$	98.9


	Six Months Ended June 30, 2023
Electric and Gas Operating Revenues (millions):	Electric		Gas			Total
Billed and Unbilled Revenue:
Residential	$	99.9	$	67.0		$	166.9
Commercial and Industrial		62.9		95.6			158.5
Other		4.6		4.6			9.2
Total Billed and Unbilled Revenue		167.4		167.2			334.6
Rate Adjustment Mechanism Revenue		5.3		(16.3	)		(11.0	)
Total Electric and Gas Operating Revenues	$	172.7	$	150.9		$	323.6


	Six Months Ended June 30, 2022
Electric and Gas Operating Revenues (millions):	Electric			Gas			Total
Billed and Unbilled Revenue:
Residential	$	83.0		$	63.6		$	146.6
Commercial and Industrial		56.7			92.7			149.4
Other		9.1			7.0			16.1
Total Billed and Unbilled Revenue		148.8			163.3			312.1
Rate Adjustment Mechanism Revenue		(5.3	)		(15.3	)		(20.6	)
Total Electric and Gas Operating Revenues	$	143.5		$	148.0		$	291.5

Revenue decoupling is the term given to the elimination of the dependency of a utility’s distribution revenue on the volume of electricity or gas sales. The difference between distribution revenue amounts billed to customers and the targeted revenue decoupling amounts is recognized as an increase or a decrease in Accrued Revenue, which forms the basis for resetting rates for future cash recoveries from, or credits to, customers. These revenue decoupling targets may be adjusted as a result of rate cases and other authorized adjustments that the Company files with the Massachusetts Department of Public Utilities (MDPU) and New Hampshire Public Utilities Commission (NHPUC). Fitchburg has been subject to revenue decoupling since 2011. Unitil Energy is subject to revenue decoupling as of June 1, 2022. As a result of Unitil Energy now being subject to revenue decoupling, as of June 1, 2022, revenue decoupling now applies to substantially all of Unitil’s total annual electric sales volumes. As a result of the 2022 final order in Northern Utilities’ base rate case in New Hampshire, substantially all of Northern Utilities’ gas sales volumes in New Hampshire are subject to decoupling as of August 1, 2022. As of August 1, 2022, the Company estimates that revenue decoupling applies to approximately 43% of Unitil’s total annual gas sales volumes. The Company's electric and gas sales in New Hampshire and Massachusetts are now largely decoupled. The following table shows the estimated percentages of electric and gas sales that are subject to revenue decoupling for the periods presented.


Revenue Decoupling
Estimated Percentage of Decoupled Sales
For Periods Presented
Electric
Before June 1, 2022	27%
After June 1, 2022	Substantially All
Gas
Before August 1, 2022	11%
After August 1, 2022	43%

Income Taxes - The Company is subject to Federal and State income taxes and various other business taxes. The Company’s process for determining income tax amounts involves estimating the Company’s current tax liabilities, and assessing temporary and permanent differences resulting from the timing of the deductions of expenses and recognition of taxable income for tax and book accounting purposes. These temporary differences result in deferred tax assets and liabilities, which are included in the Company’s Consolidated Balance Sheets. The Company accounts for income tax assets, liabilities and expenses in accordance with the Financial Accounting Standards Board (FASB) Codification guidance on Income Taxes. The Company classifies penalties and interest expense related to income tax liabilities as income tax expense and interest expense, respectively, in the Consolidated Statements of Earnings.

Provisions for income taxes are calculated in each jurisdiction in which the Company operates, for each period for which a statement of earnings is presented. The Company accounts for income taxes in accordance with the FASB Codification guidance on Income Taxes, which requires an asset and liability approach for the financial accounting and reporting of income taxes. Significant judgments and estimates are required in determining the current and deferred tax assets and liabilities. The Company’s deferred tax assets and liabilities reflect its best assessment of estimated future taxes to be paid. In accordance with the FASB Codification, the Company periodically assesses the realization of its deferred tax assets and liabilities and adjusts the income tax provision, the current tax liability and deferred taxes in the period in which the facts and circumstances which gave rise to the revision become known.

Cash and Cash Equivalents - Cash and Cash Equivalents includes all cash and cash equivalents to which the Company has legal title. Cash equivalents include short-term investments with original maturities of three months or less and interest bearing deposits. The Company’s cash and cash equivalents are held at financial institutions and at times may exceed federally insured limits. The Company has not experienced any losses in such accounts. Under the Independent System Operator—New England (ISO-NE) Financial Assurance Policy (Policy), Unitil’s subsidiaries Unitil Energy, Fitchburg and Unitil Power are required to provide assurance of their ability to satisfy their obligations to ISO-NE. Under this Policy, Unitil’s subsidiaries provide cash deposits covering approximately 2-1/2 months of outstanding obligations, less credit amounts that are based on the Company’s credit rating. As of June

30, 2023, June 30, 2022 and December 31, 2022, the Unitil subsidiaries had deposited $3.3 million, $1.7 million and $6.0 million, respectively to satisfy their ISO-NE obligations.

Allowance for Doubtful Accounts - The Company recognizes a provision for doubtful accounts that reflects the Company’s estimate of expected credit losses for electric and gas utility service accounts receivable. The allowance for doubtful accounts is calculated by applying a historical loss rate to customer account balances, and reflects management’s assessment of current and expected economic conditions, customer trends, or other factors. The Company also calculates the amount of written-off receivables that are recoverable through regulatory rate reconciling mechanisms. The Company’s distribution utilities are authorized by regulators to recover the costs of the energy commodity portion of bad debts through rate mechanisms. Also, the electric and gas divisions of Fitchburg are authorized to recover through rates past due amounts associated with protected hardship accounts. Evaluating the adequacy of the allowance for doubtful accounts requires judgment about the assumptions used in the analysis. The Company’s experience has been that the assumptions used in evaluating the adequacy of the allowance for doubtful accounts have proven to be reasonably accurate.

The Allowance for Doubtful Accounts as of June 30, 2023, June 30, 2022 and December 31, 2022, was as follows:


	June 30,				December 31,
(millions)	2023		2022		2022
Allowance for Doubtful Accounts	$	2.2	$	2.7	$	2.6

Accounts Receivable, Net includes $2.2 million, $2.6 million, and $2.5 million of the Allowance for Doubtful Accounts at June 30, 2023, June 30, 2022 and December 31, 2022, respectively. Unbilled Revenues, net (a component of Accrued Revenue) includes less than $0.1 million, $0.1 million and $0.1 million of the Allowance for Doubtful Accounts at June 30, 2023, June 30, 2022 and December 31, 2022, respectively.

Accrued Revenue - Accrued Revenue includes the current portion of Regulatory Assets and unbilled revenues. The following table shows the components of Accrued Revenue as of June 30, 2023, June 30, 2022 and December 31, 2022.


	June 30,				December 31,
Accrued Revenue (millions)	2023		2022		2022
Regulatory Assets – Current	$	56.8	$	41.4	$	66.5
Unbilled Revenues, net		3.6		4.2		6.3
Total Accrued Revenue	$	60.4	$	45.6	$	72.8

Exchange Gas Receivable - Northern Utilities and Fitchburg have gas exchange and storage agreements whereby gas purchases during the months of April through October are delivered to a third party. The third party delivers gas back to the Company during the months of November through March. The exchange and storage gas volumes are recorded at weighted average cost. The following table shows the components of Exchange Gas Receivable as of June 30, 2023, June 30, 2022 and December 31, 2022.


	June 30,				December 31,
Exchange Gas Receivable (millions)	2023		2022		2022
Northern Utilities	$	8.7	$	12.5	$	16.3
Fitchburg		0.7		0.9		1.7
Total Exchange Gas Receivable	$	9.4	$	13.4	$	18.0

Gas Inventory - The Company uses the weighted average cost methodology to value gas inventory. The following table shows the components of Gas Inventory as of June 30, 2023, June 30, 2022 and December 31, 2022.


	June 30,				December 31,
Gas Inventory (millions)	2023		2022		2022
Natural Gas	$	0.6	$	0.5	$	1.0
Propane		0.3		0.4		0.4
Liquefied Natural Gas & Other		0.1		0.1		0.4
Total Gas Inventory	$	1.0	$	1.0	$	1.8

Utility Plant - The cost of additions to Utility Plant and the cost of renewals and betterments are capitalized. Cost consists of labor, materials, services and certain indirect construction costs, including an allowance for funds used during construction (AFUDC). The costs of current repairs and minor replacements are charged to appropriate operating expense accounts. The original cost of utility plant retired or otherwise disposed of is charged to the accumulated provision for depreciation. The Company includes in its mass

asset depreciation rates, which are periodically reviewed as part of its ratemaking proceedings, cost of removal amounts to provide for future negative salvage value. At June 30, 2023, June 30, 2022 and December 31, 2022, the cost of removal amounts, which are recorded on the Consolidated Balance Sheets in Cost of Removal Obligations, were estimated to be $123.2 million, $112.4 million, and $116.1 million, respectively.

Leases - The Company records assets and liabilities on the balance sheet for all leases with terms longer than 12 months. Leases are classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. The Company has elected the practical expedient to not separate non-lease components from lease components and instead to account for both as a single lease component. The Company’s accounting policy election for leases with a lease term of 12 months or less is to recognize the lease payments as lease expense in the Consolidated Statements of Earnings on a straight-line basis over the lease term. See additional discussion in the “Leases” section of Note 4 (Debt and Financing Arrangements).

Regulatory Accounting - The Company’s principal business is the distribution of electricity and natural gas by the three distribution utilities: Unitil Energy, Fitchburg and Northern Utilities. Unitil Energy and Fitchburg are subject to regulation by the FERC. Fitchburg is also regulated by the MDPU, Unitil Energy is regulated by the NHPUC and Northern Utilities is regulated by the MPUC and NHPUC. Granite State, the Company’s natural gas transmission pipeline, is regulated by the FERC. Accordingly, the Company uses the Regulated Operations guidance as set forth in the FASB Codification. The Company has recorded Regulatory Assets and Regulatory Liabilities which will be recovered from customers, or applied for customer benefit, in accordance with rate provisions approved by the applicable public utility regulatory commission. The electric and gas divisions of Fitchburg are authorized to recover through rates past due amounts associated with hardship accounts that are protected from shut-off. As of June 30, 2023, June 30, 2022 and December 31, 2022, the Company has recorded $6.0 million, $7.6 million and $5.8 million, respectively, of hardship accounts in Regulatory Assets. These amounts are included in “Other Deferred Charges” in the following table. The Company currently receives recovery in rates or expects to receive recovery of these hardship accounts in future rate cases.


	June 30,				December 31,
Regulatory Assets consist of the following (millions)	2023		2022		2022
Retirement Benefits	$	27.2	$	86.9	$	29.1
Energy Supply and Other Rate Adjustment Mechanisms		54.0		38.2		63.0
Deferred Storm Charges		8.5		2.9		3.4
Environmental		6.1		4.5		5.9
Income Taxes		1.5		2.2		1.8
Other Deferred Charges		11.0		13.3		11.1
Total Regulatory Assets		108.3		148.0		114.3
Less: Current Portion of Regulatory Assets(1)		56.8		41.4		66.5
Regulatory Assets – noncurrent	$	51.5	$	106.6	$	47.8

(1)

Reflects amounts included in the Accrued Revenue on the Company’s Consolidated Balance Sheets.


	June 30,				December 31,
Regulatory Liabilities consist of the following (millions)	2023		2022		2022
Income Taxes (Note 8)	$	39.6	$	42.6	$	41.0
Rate Adjustment Mechanisms		14.3		22.2		10.9
Total Regulatory Liabilities		53.9		64.8		51.9
Less: Current Portion of Regulatory Liabilities		18.4		25.9		15.0
Regulatory Liabilities – noncurrent	$	35.5	$	38.9	$	36.9

Generally, the Company receives a return on investment on its regulatory assets for which a cash outflow has been made. Included in Regulatory Assets as of June 30, 2023 are $5.5 million of environmental costs, rate case costs and other expenditures to be recovered over varying periods in the next seven years. Regulators have authorized recovery of these expenditures, but without a return. Regulatory commissions can reach different conclusions about the recovery of costs, which can have a material effect on the Company’s Consolidated Financial Statements. The Company believes it is probable that its regulated distribution and transmission utilities will recover their investments in long-lived assets, including regulatory assets. If the Company, or a portion of its assets or operations, were to cease meeting the criteria for application of these accounting rules, accounting standards for businesses in general would become applicable and immediate recognition of any previously deferred costs, or a portion of deferred costs, would be required in the year in which the criteria are no longer met, if such deferred costs were not recoverable in the portion of the business that continues to meet the criteria for application of the FASB Codification topic on Regulated Operations. If unable to continue to apply the FASB Codification provisions for Regulated Operations, the Company would be required to apply the provisions for the Discontinuation of Rate-Regulated Accounting included in the FASB Codification. In the Company’s opinion, its regulated operations will be subject to the FASB Codification provisions for Regulated Operations for the foreseeable future.

Derivatives - The Company’s regulated energy subsidiaries enter into energy supply contracts to serve their electric and gas customers. The Company follows a procedure for determining whether each contract qualifies as a derivative instrument under the guidance provided by the FASB Codification on Derivatives and Hedging. For each contract, the Company reviews and documents the key terms of the contract. Based on those terms and any additional relevant components of the contract, the Company determines and documents whether the contract qualifies as a derivative instrument as defined in the FASB Codification. The Company has determined that its energy supply contracts either do not qualify as a derivative instrument under the guidance set forth in the FASB Codification, have been elected as a normal purchase, or have contingencies that have not yet been met in order to establish a notional amount.

Fitchburg has entered into power purchase agreements for which contingencies exist (see Note 6, Regulatory Matters—Fitchburg—Massachusetts Request for Proposal (RFPs)). Until these contingencies are satisfied, these contracts will not qualify for derivative accounting. The Company believes that the power purchase obligations under these long-term contracts will have a material effect on the contractual obligations of Fitchburg.

Investments in Marketable Securities - The Company maintains a trust through which it invests in a money market fund. This fund is intended to satisfy obligations under the Company’s Supplemental Executive Retirement Plan (SERP) (See additional discussion of the SERP in Note 9).

At June 30, 2023, June 30, 2022 and December 31, 2022, the fair value of the Company’s investments in these trading securities, which are recorded on the Consolidated Balance Sheets in Other Assets, was $5.8 million, $5.4 million and $5.8 million, respectively, as shown in the following table. These investments are valued based on quoted prices from active markets and are categorized in Level 1 as they are actively traded and no valuation adjustments have been applied. Changes in the fair value of these investments are recorded in Other Expense, Net.


	June 30,				December 31,
Fair Value of Marketable Securities (millions)	2023		2022		2022
Money Market Funds	$	5.8	$	5.4	$	5.8
Total Marketable Securities	$	5.8	$	5.4	$	5.8

The Company also sponsors the Unitil Corporation Deferred Compensation Plan (the “DC Plan”). The DC Plan is a non-qualified deferred compensation plan that provides a vehicle for participants to accumulate tax-deferred savings to supplement retirement income. The DC Plan, which was effective January 1, 2019, is open to senior management or other highly compensated employees as determined by the Company’s Board of Directors, and may also be used for recruitment and retention purposes for newly hired senior executives. The DC Plan design mirrors the Company’s Tax Deferred Savings and Investment Plan formula, but provides for contributions on compensation above the IRS limit, which will allow participants to defer up to 85% of base salary, and up to 85% of any cash incentive for retirement. The Company may also elect to make discretionary contributions on behalf of any participant in an amount determined by the Company’s Board of Directors. A trust has been established to invest the funds associated with the DC Plan.

At June 30, 2023, June 30, 2022 and December 31, 2022, the fair value of the Company’s investments in these trading securities related to the DC Plan, which are recorded on the Consolidated Balance Sheets in Other Assets, were $1.1 million, $0.8 million and $0.6 million, respectively, as shown in the following table. These investments are valued based on quoted prices from active markets and are categorized in Level 1 as they are actively traded and no valuation adjustments have been applied. Changes in the fair value of these investments are recorded in Other Expense, Net.


	June 30,				December 31,
Fair Value of Marketable Securities (millions)	2023		2022		2022
Equity Funds	$	1.0	$	0.4	$	0.5
Money Market Funds		0.1		0.4		0.1
Total Marketable Securities	$	1.1	$	0.8	$	0.6

Energy Supply Obligations - The following discussion and table summarize the nature and amounts of the items recorded as Energy Supply Obligations (current portion) and Other Noncurrent Liabilities (noncurrent portion) on the Company’s Consolidated Balance Sheets.


	June 30,				December 31,
Energy Supply Obligations (millions)	2023		2022		2022
Current:
Exchange Gas Obligation	$	8.7	$	12.5	$	16.3
Renewable Energy Portfolio Standards		5.2		4.1		7.8
Total Energy Supply Obligations	$	13.9	$	16.6	$	24.1

Exchange Gas Obligation - Northern Utilities enters into gas exchange agreements under which Northern Utilities releases certain gas pipeline and storage assets, sells the gas storage inventory to an asset manager and subsequently repurchases the inventory over the course of the gas heating season at the same price at which it sold the gas inventory to the asset manager. The gas inventory related to these agreements is recorded in Exchange Gas Receivable on the Company’s Consolidated Balance Sheets while the corresponding obligations are recorded in Energy Supply Obligations.

Renewable Energy Portfolio Standards - Renewable Energy Portfolio Standards (RPS) require retail electricity suppliers, including public utilities, to demonstrate that required percentages of their sales are met with power generated from certain types of resources or technologies. Compliance is demonstrated by purchasing and retiring Renewable Energy Certificates (REC) generated by facilities approved by the state as qualifying for REC treatment. Unitil Energy and Fitchburg purchase RECs in compliance with RPS legislation in New Hampshire and Massachusetts for supply provided to default service customers. RPS compliance costs are a supply cost that is recovered in customer default service rates. Unitil Energy and Fitchburg collect RPS compliance costs from customers throughout the year and demonstrate compliance for each calendar year on the following July 1. Due to timing differences between collection of revenue from customers and payment of REC costs to suppliers, Unitil Energy and Fitchburg typically defer costs for RPS compliance which are recorded within Accrued Revenue with a corresponding liability in Energy Supply Obligations on the Company’s Consolidated Balance Sheets.

Fitchburg has entered into long-term renewable contracts for the purchase of clean energy and/or RECs pursuant to Massachusetts legislation, specifically, An Act Relative to Green Communities (Green Communities Act, 2008), An Act Relative to Competitively Priced Electricity in the Commonwealth (2012) and An Act to Promote Energy Diversity (Energy Diversity Act, 2016). The generating facilities associated with ten of these contracts have been constructed and are now operating. Three approved contracts are currently under development. These include two long-term contracts filed with the MDPU in 2018, one for offshore wind generation and one for imported hydroelectric power and associated transmission, both of which were approved in 2019, and another for offshore wind generation filed with the MDPU during the first quarter of 2020 and approved in 2021. In compliance with An Act to Promote a Clean Energy Future (2018), in 2021, in coordination with the other electric utilities in Massachusetts, the Company issued its most recent long-term renewable solicitation seeking up to an additional 1,600 megawatts (MW) of offshore wind generation. In December 2021, a portfolio of projects comprising 1,600 MW of offshore wind capacity was selected for negotiation. Those contracts were approved by the MDPU on December 30, 2022. Fitchburg recovers the costs associated with long-term renewable contracts on a fully reconciling basis through a MDPU-approved cost recovery mechanism, and has received remuneration for entering into them.

Power Supply Contract Divestitures - Unitil Energy’s and Fitchburg’s customers are entitled to purchase their electric or natural gas supplies from third-party suppliers. In connection with the implementation of retail choice, Unitil Power, which formerly functioned as the wholesale power supply provider for Unitil Energy, and Fitchburg divested their long-term power supply contracts through the sale of the entitlements to the electricity sold under those contracts. Unitil Energy and Fitchburg recover in their rates all the costs associated with the divestiture of their power supply portfolios and have secured regulatory approval from the NHPUC and MDPU, respectively, for the recovery of power supply-related stranded costs. As of June 30, 2023, Fitchburg and Unitil Energy have fully recovered their power supply-related stranded costs.

Subsequent Events - The Company evaluates all events or transactions through the date of the related filing. During the period through the date of this filing, the Company did not have any material subsequent events, except for the Fitchburg issuance of $25 million of Notes on July 6, 2023, as disclosed in Note 4, that would result in adjustment to or disclosure in its Consolidated Financial Statements.

Company's Liability for Environmental Obligations (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Environmental Exit Cost [Line Items]
Total Balance at Beginning of Period	$ 4.4	$ 2.7
Additions	0.5	0.3
Less: Payments / Reductions	0.2	0.2
Total Balance at End of Period	4.7	2.8
Less: Current Portion	0.6	0.6	$ 0.6
Noncurrent Balance at End of Period	$ 4.1	$ 2.2	$ 3.8

Components of Gas and Electric Operating Revenue (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	$ 103.4	$ 98.9	$ 323.6	$ 291.5
Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	115.1	113.7	334.6	312.1
Rate Adjustment Mechanism Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	(11.7)	(14.8)	(11.0)	(20.6)
Electric
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	64.5	54.3	172.7	143.5
Electric \| Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	69.8	64.1	167.4	148.8
Electric \| Rate Adjustment Mechanism Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	(5.3)	(9.8)	5.3	(5.3)
Gas Segment
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	38.9	44.6	150.9	148.0
Gas Segment \| Billed and Unbilled Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	45.3	49.6	167.2	163.3
Gas Segment \| Rate Adjustment Mechanism Revenue
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	(6.4)	(5.0)	(16.3)	(15.3)
Residential
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	57.7	51.9	166.9	146.6
Residential \| Electric
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	39.8	33.8	99.9	83.0
Residential \| Gas Segment
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	17.9	18.1	67.0	63.6
Commercial & Industrial
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	54.5	53.7	158.5	149.4
Commercial & Industrial \| Electric
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	28.1	25.7	62.9	56.7
Commercial & Industrial \| Gas Segment
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	26.4	28.0	95.6	92.7
Other
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	2.9	8.1	9.2	16.1
Other \| Electric
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	1.9	4.6	4.6	9.1
Other \| Gas Segment
Operating Revenues [Line Items]
Total Gas and Electric Operating Revenues	$ 1.0	$ 3.5	$ 4.6	$ 7.0

- Definition

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

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+ Details

Pay vs Performance Disclosure - USD ($) $ in Millions	3 Months Ended		6 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Millions	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ 4.2	$ 4.9	$ 28.3	$ 26.4

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Consolidated Statements Of Changes In Common Stock Equity (Unaudited) - USD ($) $ in Millions	Total	Common Equity	Retained Earnings
Beginning Balance at Dec. 31, 2021	$ 448.3	$ 332.1	$ 116.2
Net Income	26.4		26.4
Dividends on Common Shares	(12.6)		(12.6)
Stock Compensation Plans	1.5	1.5
Issuance of Common Shares	0.5	0.5
Ending Balance at Jun. 30, 2022	464.1	334.1	130.0
Beginning Balance at Mar. 31, 2022	465.1	333.7	131.4
Net Income	4.9		4.9
Dividends on Common Shares	(6.3)		(6.3)
Stock Compensation Plans	0.2	0.2
Issuance of Common Shares	0.2	0.2
Ending Balance at Jun. 30, 2022	464.1	334.1	130.0
Beginning Balance at Dec. 31, 2022	467.4	334.9	132.5
Net Income	28.3		28.3
Dividends on Common Shares	(13.1)		(13.1)
Stock Compensation Plans	1.0	1.0
Issuance of Common Shares	0.6	0.6
Ending Balance at Jun. 30, 2023	484.2	336.5	147.7
Beginning Balance at Mar. 31, 2023	486.2	336.1	150.1
Net Income	4.2		4.2
Dividends on Common Shares	(6.6)		(6.6)
Stock Compensation Plans	0.1	0.1
Issuance of Common Shares	0.3	0.3
Ending Balance at Jun. 30, 2023	$ 484.2	$ 336.5	$ 147.7

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

- Definition

Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering.

+ References + Details

Environmental Matters - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2023 USD ($)
Site Contingency [Line Items]
Remediation costs	$ 5.6
Environmental Restoration Costs
Site Contingency [Line Items]
Estimated Costs Accrued For Remediation	$ 2.5
Maine \| Environmental Restoration Costs
Site Contingency [Line Items]
Amortization period for environmental costs	5 years

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References + Details

Retirement Benefit obligations

6 Months Ended

Jun. 30, 2023

Retirement Benefits [Abstract]

Retirement Benefit obligations

Note 9: Retirement Benefit obligations

The Company co-sponsors the Unitil Corporation Retirement Plan (Pension Plan), the Unitil Retiree Health and Welfare Benefits Plan (PBOP Plan), and the Unitil Corporation SERP to provide certain pension and postretirement benefits for its retirees and current employees. Refer to Note 9 to the Consolidated Financial Statements in the Company’s Form 10-K for the year ended December 31, 2022 as filed with the SEC on February 14, 2023 for additional information regarding these plans.

The following table includes the key weighted average assumptions used in determining the Company’s benefit plan costs and obligations:


Used to Determine Plan Costs	2023			2022
Discount Rate		5.25	%		2.85	%
Rate of Compensation Increase		3.00	%		3.00	%
Expected Long-term rate of return on plan assets		7.50	%		7.50	%

The health care cost trend rate used to determine benefit plan costs for 2023 for pre-65 retirees is 8.00%, with an ultimate rate of 4.50% in 2030, and for post-65 retirees, the health care cost trend rate is 6.25%, with an ultimate rate of 4.50% in 2030. The health care cost trend rate used to determine benefit plan costs for 2022 for both pre-65 and post-65 retirees is 6.20%, with an ultimate rate 4.50% in 2029.

The following tables provide the components of the Company’s Retirement plan costs ($000’s):


	Pension Plan						PBOP Plan						SERP
For the Three Months Ended June 30,	2023			2022			2023			2022			2023			2022
Service Cost	$	523		$	791		$	373		$	722		$	63		$	68
Interest Cost		1,870			1,371			725			799			188			118
Expected Return on Plan Assets		(2,672	)		(2,720	)		(852	)		(854	)		—			—
Prior Service Cost Amortization		88			89			199			273			14			14
Actuarial Loss Amortization		—			1,377			(366	)		255			—			199
Sub-total		(191	)		908			79			1,195			265			399
Amounts Capitalized and Deferred		366			(309	)		112			(622	)		(82	)		(119	)
Net Periodic Benefit Cost Recognized	$	175		$	599		$	191		$	573		$	183		$	280


	Pension Plan						PBOP Plan						SERP
For the Six Months Ended June 30,	2023			2022			2023			2022			2023			2022
Service Cost	$	1,046		$	1,582		$	746		$	1,444		$	125		$	136
Interest Cost		3,740			2,742			1,450			1,598			377			236
Expected Return on Plan Assets		(5,344	)		(5,440	)		(1,704	)		(1,708	)		—			—
Prior Service Cost Amortization		177			178			397			546			28			28
Actuarial Loss Amortization		—			2,754			(732	)		510			—			399
Sub-total		(381	)		1,816			157			2,390			530			799
Amounts Capitalized and Deferred		864			(464	)		333			(1,133	)		(164	)		(238	)
Net Periodic Benefit Cost Recognized	$	483		$	1,352		$	490		$	1,257		$	366		$	561

Employer Contributions

As of June 30, 2023, the Company had made contributions of $1.9 million and $0.6 million, to its Pension Plan and PBOP Plan, respectively, in 2023. The Company, along with its subsidiaries, expects to make contributions to its Pension and PBOP Plans in 2023 and future years at minimum required and discretionary funding levels consistent with the amounts recovered in the distribution utilities’ rates for these Pension and PBOP Plan costs.

As of June 30, 2023, the Company had made $0.3 million of benefit payments under the SERP Plan in 2023. The Company presently anticipates making an additional $0.3 million of benefit payments under the SERP Plan in 2023.

- Definition

The entire disclosure for retirement benefits.

+ References

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-Publisher FASB
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+ Details

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended		6 Months Ended		12 Months Ended
	Aug. 31, 2022	Dec. 31, 2020	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2017
Income Taxes [Line Items]
Corporate federal income tax			21.00%	21.00%
Regulatory liability, expected flow back to customers							$ 47.1
Regulatory liability, expected pass back to ratepayers					$ 1.0
Net Operating Loss Carryforwards Utilized For Income Taxes						$ 2.4
Deferred tax assets, operating loss carryforwards, federal					$ 2.8	$ 5.3
Percentage of employment retention credit			50.00%
Employment retention duties capacity			100.00%
Percentage of alternate minimum tax	15.00%
Adjustment financial statement income	$ 1,000.0
Number of years used for calculating adjusted financial statement income	3 years
Consolidated Appropriations Act 2021 [Member]
Income Taxes [Line Items]
Percentage of employment retention credit		70.00%
Employment retention duties capacity		100.00%
Gas Ratepayers \| Massachusetts And Maine [Member]
Income Taxes [Line Items]
Regulatory liability, expected flow back to customers			$ 7.8
Tax Year 2018
Income Taxes [Line Items]
Corporate federal income tax							21.00%	21.00%

Significant Segment Financial Data (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	$ 103.4	$ 98.9	$ 323.6	$ 291.5
Segment Profit (Loss)	4.2	4.9	28.3	26.4
Capital Expenditures	35.4	29.9	57.6	45.3
Segment Assets	1,595.3	1,547.1	1,595.3	1,547.1	$ 1,590.4
Billed and Unbilled Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	115.1	113.7	334.6	312.1
Rate Adjustment Mechanism Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	(11.7)	(14.8)	(11.0)	(20.6)
Gas Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	38.9	44.6	150.9	148.0
Segment Profit (Loss)	0.9	1.3	19.9	19.8
Capital Expenditures	22.0	22.0	33.5	31.0
Segment Assets	961.9	936.0	961.9	936.0
Gas Segment \| Billed and Unbilled Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	45.3	49.6	167.2	163.3
Gas Segment \| Rate Adjustment Mechanism Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	(6.4)	(5.0)	(16.3)	(15.3)
Electric
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	64.5	54.3	172.7	143.5
Segment Profit (Loss)	3.6	3.9	8.9	7.3
Capital Expenditures	13.4	7.9	24.0	14.2
Segment Assets	610.5	593.0	610.5	593.0
Electric \| Billed and Unbilled Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	69.8	64.1	167.4	148.8
Electric \| Rate Adjustment Mechanism Revenue
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total Operating Revenues	(5.3)	(9.8)	5.3	(5.3)
All Other Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment Profit (Loss)	(0.3)	(0.3)	(0.5)	(0.7)
Capital Expenditures			0.1	0.1
Segment Assets	$ 22.9	$ 18.1	$ 22.9	$ 18.1

Debt and Financing Arrangements (Tables)

6 Months Ended

Jun. 30, 2023

Details on Long Term Debt

Details on long-term debt at June 30, 2023, June 30, 2022 and December 31, 2022 are shown below.


(millions)	June 30,				December 31,
	2023		2022		2022
Unitil Corporation:
3.70% Senior Notes, Due August 1, 2026	$	30.0	$	30.0	$	30.0
3.43% Senior Notes, Due December 18, 2029		30.0		30.0		30.0
Unitil Energy First Mortgage Bonds:
8.49% Senior Secured Notes, Due October 14, 2024		—		1.5		—
6.96% Senior Secured Notes, Due September 1, 2028		12.0		14.0		12.0
8.00% Senior Secured Notes, Due May 1, 2031		12.0		13.5		13.5
6.32% Senior Secured Notes, Due September 15, 2036		15.0		15.0		15.0
3.58% Senior Secured Notes, Due September 15, 2040		27.5		27.5		27.5
4.18% Senior Secured Notes, Due November 30, 2048		30.0		30.0		30.0
Fitchburg:
6.79% Senior Notes, Due October 15, 2025		2.0		6.0		2.0
3.52% Senior Notes, Due November 1, 2027		10.0		10.0		10.0
7.37% Senior Notes, Due January 15, 2029		7.2		8.4		8.4
5.90% Senior Notes, Due December 15, 2030		15.0		15.0		15.0
7.98% Senior Notes, Due June 1, 2031		14.0		14.0		14.0
3.78% Senior Notes, Due September 15, 2040		27.5		27.5		27.5
4.32% Senior Notes, Due November 1, 2047		15.0		15.0		15.0
Northern Utilities:
3.52% Senior Notes, Due November 1, 2027		20.0		20.0		20.0
7.72% Senior Notes, Due December 3, 2038		50.0		50.0		50.0
3.78% Senior Notes, Due September 15, 2040		40.0		40.0		40.0
4.42% Senior Notes, Due October 15, 2044		50.0		50.0		50.0
4.32% Senior Notes, Due November 1, 2047		30.0		30.0		30.0
4.04% Senior Notes, Due September 12, 2049		40.0		40.0		40.0
Granite State:
3.72% Senior Notes, Due November 1, 2027		15.0		15.0		15.0
Unitil Realty Corp.:
2.64% Senior Secured Notes, Due December 18, 2030		4.1		4.4		4.2
Total Long-Term Debt		496.3		506.8		499.1
Less: Unamortized Debt Issuance Costs		3.2		3.5		3.3
Total Long-Term Debt, net of Unamortized Debt Issuance Costs		493.1		503.3		495.8
Less: Current Portion		6.9		8.2		6.7
Total Long-term Debt, Less Current Portion	$	486.2	$	495.1	$	489.1

Fair Value of Long Term Debt


(millions)	June 30,				December 31,
	2023		2022		2022
Estimated Fair Value of Long-Term Debt	$	446.2	$	477.3	$	455.3

Borrowing Limits Amounts Outstanding and Amounts Available under Credit Facility

The following table details the borrowing limits, amounts outstanding and amounts available under the Credit Facility as of June 30, 2023 and December 31, 2022 and for the prior credit facility as of June 30, 2022:


	Revolving Credit Facility (millions)
	June 30,				December 31,
	2023		2022		2022
Limit	$	200.0	$	120.0	$	200.0
Short-Term Borrowings Outstanding		131.7		46.2		116.0
Available	$	68.3	$	73.8	$	84.0

Classification of the Company Lease Obligations

The balance sheet classification of the Company’s lease obligations was as follows:


	June 30,				December 31,
Lease Obligations (millions)	2023		2022		2022
Operating Lease Obligations:
Other Current Liabilities (current portion)	$	1.7	$	1.5	$	1.5
Other Noncurrent Liabilities (long-term portion)		3.5		2.9		2.8
Total Operating Lease Obligations		5.2		4.4		4.3
Capital Lease Obligations:
Other Current Liabilities (current portion)		0.1		0.1		0.1
Other Noncurrent Liabilities (long-term portion)		0.3		0.1		0.1
Total Capital Lease Obligations		0.4		0.2		0.2
Total Lease Obligations	$	5.6	$	4.6	$	4.5

Future Operating Lease Payment Obligations and Future Minimum Lease Payments under Capital Leases

The following table is a schedule of future operating lease payment obligations and future minimum lease payments under capital leases as of June 30, 2023. The payments for operating leases consist of $1.7 million of current operating lease obligations, which are included in Other Current Liabilities and $3.5 million of noncurrent operating lease obligations, which are included in Other Noncurrent Liabilities, on the Company’s Consolidated Balance Sheets as of June 30, 2023. The payments for capital leases consist of $0.1 million of current capital lease obligations, which are included in Other Current Liabilities and $0.3 million of noncurrent capital lease obligations, which are included in Other Noncurrent Liabilities, on the Company’s Consolidated Balance Sheets as of June 30, 2023.


Lease Payments ($000’s)	Operating		Capital
Year Ending December 31,	Leases		Leases
Rest of 2023	$	1,040	$	71
2024		1,761		118
2025		1,189		86
2026		890		74
2027		613		70
2028 - 2032		238		2
Total Payments		5,731		421
Less: Interest		484		24
Amount of Lease Obligations Recorded on Consolidated Balance Sheets	$	5,247	$	397

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

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-URI https://asc.fasb.org//1943274/2147482949/835-30-55-8

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 942
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-URI https://asc.fasb.org//1943274/2147480848/942-470-50-3

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 11: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
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-URI https://asc.fasb.org//1943274/2147481112/505-10-50-6

Reference 12: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481112/505-10-50-7

+ Details

Segment Information

6 Months Ended

Jun. 30, 2023

Segment Information

note 3 - Segment Information

The following table provides significant segment financial data for the three and six months ended June 30, 2023 and June 30, 2022.


	Electric			Gas			Other			Total
Three Months Ended June 30, 2023 (millions)
Revenues:
Billed and Unbilled Revenue	$	69.8		$	45.3		$	—		$	115.1
Rate Adjustment Mechanism Revenue		(5.3	)		(6.4	)		—			(11.7	)
Total Operating Revenues		64.5			38.9			—			103.4
Segment Profit (Loss)		3.6			0.9			(0.3	)		4.2
Capital Expenditures		13.4			22.0			—			35.4

Three Months Ended June 30, 2022 (millions)
Revenues:
Billed and Unbilled Revenue	$	64.1		$	49.6		$	—		$	113.7
Rate Adjustment Mechanism Revenue		(9.8	)		(5.0	)		—			(14.8	)
Total Operating Revenues		54.3			44.6			—			98.9
Segment Profit (Loss)		3.9			1.3			(0.3	)		4.9
Capital Expenditures		7.9			22.0			—			29.9

Six Months Ended June 30, 2023 (millions)
Revenues:
Billed and Unbilled Revenue	$	167.4		$	167.2		$	—		$	334.6
Rate Adjustment Mechanism Revenue		5.3			(16.3	)		—			(11.0	)
Total Operating Revenues		172.7			150.9			—			323.6
Segment Profit (Loss)		8.9			19.9			(0.5	)		28.3
Capital Expenditures		24.0			33.5			0.1			57.6
Segment Assets		610.5			961.9			22.9			1,595.3

Six Months Ended June 30, 2022 (millions)
Revenues:
Billed and Unbilled Revenue	$	148.8		$	163.3		$	—		$	312.1
Rate Adjustment Mechanism Revenue		(5.3	)		(15.3	)		—			(20.6	)
Total Operating Revenues		143.5			148.0			—			291.5
Segment Profit (Loss)		7.3			19.8			(0.7	)		26.4
Capital Expenditures		14.2			31.0			0.1			45.3
Segment Assets		593.0			936.0			18.1			1,547.1

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-15

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-42

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 40
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-40

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//280/tableOfContent

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 26
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-26

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 34
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-34

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 41
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-41

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-21

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-21

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

+ Details

Consolidated Balance Sheets (Parenthetical) - shares	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Statement of Financial Position [Abstract]
Common Stock Authorized	25,000,000	25,000,000	25,000,000
Common Equity Outstanding	16,091,419	16,043,355	16,034,635

Debt and Financing Arrangements - Details on Long Term Debt (Detail) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Debt Instrument [Line Items]
Total Long-Term Debt	$ 496.3	$ 499.1	$ 506.8
Less: Unamortized Debt Issuance Costs	3.2	3.3	3.5
Long-Term Debt	493.1	495.8	503.3
Less: Current Portion	6.9	6.7	8.2
Total Long-Term Debt, Less Current Portion	486.2	489.1	495.1
3.70% Senior Notes, Due August 1, 2026
Debt Instrument [Line Items]
Total Long-Term Debt	30.0	30.0	30.0
3.43% Senior Notes, Due December 18, 2029
Debt Instrument [Line Items]
Total Long-Term Debt	30.0	30.0	30.0
Unitil Energy Systems Inc \| First Mortgage Bonds 8.49% Senior Secured Notes, Due October 14, 2024
Debt Instrument [Line Items]
Total Long-Term Debt			1.5
Unitil Energy Systems Inc \| First Mortgage Bonds 6.96% Senior Secured Notes, Due September 1, 2028
Debt Instrument [Line Items]
Total Long-Term Debt	12.0	12.0	14.0
Unitil Energy Systems Inc \| First Mortgage Bonds 8.00% Senior Secured Notes, Due May 1, 2031
Debt Instrument [Line Items]
Total Long-Term Debt	12.0	13.5	13.5
Unitil Energy Systems Inc \| First Mortgage Bonds 6.32% Senior Secured Notes, Due September 15, 2036
Debt Instrument [Line Items]
Total Long-Term Debt	15.0	15.0	15.0
Unitil Energy Systems Inc \| First Mortgage Bonds 4.18% Senior Secured Notes Due November 30, 2048
Debt Instrument [Line Items]
Total Long-Term Debt	30.0	30.0	30.0
Unitil Energy Systems Inc \| 3.58% Senior Secured Notes, Due September 15, 2040
Debt Instrument [Line Items]
Total Long-Term Debt	27.5	27.5	27.5
Fitchburg Gas and Electric Light Company \| 6.79% Senior Notes, Due October 15, 2025
Debt Instrument [Line Items]
Total Long-Term Debt	2.0	2.0	6.0
Fitchburg Gas and Electric Light Company \| 3.52% Senior Notes, Due November 1, 2027
Debt Instrument [Line Items]
Total Long-Term Debt	10.0	10.0	10.0
Fitchburg Gas and Electric Light Company \| 7.37% Notes, Due January 15, 2029
Debt Instrument [Line Items]
Total Long-Term Debt	7.2	8.4	8.4
Fitchburg Gas and Electric Light Company \| 5.90% Notes, Due December 15, 2030
Debt Instrument [Line Items]
Total Long-Term Debt	15.0	15.0	15.0
Fitchburg Gas and Electric Light Company \| 7.98% Notes, Due June 1, 2031
Debt Instrument [Line Items]
Total Long-Term Debt	14.0	14.0	14.0
Fitchburg Gas and Electric Light Company \| 4.32% Senior Notes, Due November 1, 2047
Debt Instrument [Line Items]
Total Long-Term Debt	15.0	15.0	15.0
Fitchburg Gas and Electric Light Company \| 3.78% Senior Notes, Due September 15, 2040
Debt Instrument [Line Items]
Total Long-Term Debt	27.5	27.5	27.5
Northern Utilities Inc \| 3.52% Senior Notes, Due November 1, 2027
Debt Instrument [Line Items]
Total Long-Term Debt	20.0	20.0	20.0
Northern Utilities Inc \| 3.78% Senior Notes, Due September 15, 2040
Debt Instrument [Line Items]
Total Long-Term Debt	40.0	40.0	40.0
Northern Utilities Inc \| 4.32% Senior Notes, Due November 1, 2047
Debt Instrument [Line Items]
Total Long-Term Debt	30.0	30.0	30.0
Northern Utilities Inc \| 7.72% Senior Notes, Due December 3, 2038
Debt Instrument [Line Items]
Total Long-Term Debt	50.0	50.0	50.0
Northern Utilities Inc \| 4.42% Senior Notes, Due October 15, 2044
Debt Instrument [Line Items]
Total Long-Term Debt	50.0	50.0	50.0
Northern Utilities Inc \| 4.04% Senior Notes, Due September 12, 2049
Debt Instrument [Line Items]
Total Long-Term Debt	40.0	40.0	40.0
Granite State Gas Transmission Inc \| 3.72% Senior Notes, Due November 1, 2027
Debt Instrument [Line Items]
Total Long-Term Debt	15.0	15.0	15.0
Unitil Realty Corp Member \| 2.64% Senior Secured Notes, Due December 18, 2030
Debt Instrument [Line Items]
Total Long-Term Debt	$ 4.1	$ 4.2	$ 4.4

Common Stock and Preferred Stock (Tables)

6 Months Ended

Jun. 30, 2023

Table Text Block Supplement [Abstract]

Restricted Stock Units Issued

The equity portion of Restricted Stock Units activity during the six months ended June 30, 2023 in conjunction with the Stock Plan is presented in the following table:


Restricted Stock Units (Equity Portion)
	Units		Weighted Average Stock Price
Restricted Stock Units as of December 31, 2022		43,799	$	40.17
Restricted Stock Units Granted		—	$	—
Dividend Equivalents Earned		669	$	53.24
Restricted Stock Units Settled		—	$	—
Restricted Stock Units as of June 30, 2023		44,468	$	40.37

Debt and Financing Arrangements - Future Operating Lease Payment Obligations and Future Minimum Lease Payments under Capital Leases (Detail) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Operating leases
Rest of 2023	$ 1,040.0
2024	1,761.0
2025	1,189.0
2026	890.0
2027	613.0
2028-2032	238.0
Total Payments	5,731.0
Less: Interest	484.0
Amount of Lease Obligations Recorded on Consolidated Balance Sheets	5.2	$ 4.3	$ 4.4
Capital leases
Rest of 2023	71.0
2024	118.0
2025	86.0
2026	74.0
2027	70.0
2028-2032	2.0
Total Payments	421.0
Less: Interest	24.0
Lease Obligations [Member]
Operating leases
Amount of Lease Obligations Recorded on Consolidated Balance Sheets	5,247.0
Capital leases
Amount of Lease Obligations Recorded on Consolidated Balance Sheets	$ 397.0

Components of Energy Supply Obligations (Detail) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Contractual Obligation [Line Items]
Energy Supply Obligations-Current	$ 13.9	$ 24.1	$ 16.6
Exchange Gas Obligation
Contractual Obligation [Line Items]
Energy Supply Obligations-Current	8.7	16.3	12.5
Renewable Energy Portfolio Standards
Contractual Obligation [Line Items]
Energy Supply Obligations-Current	$ 5.2	$ 7.8	$ 4.1

Dividends Declared Per Share (Detail) - $ / shares	3 Months Ended		6 Months Ended
Dividends Declared Per Share (Detail) - $ / shares	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Dividends Payable [Line Items]
Dividend Amount	$ 0.405	$ 0.39	$ 0.81	$ 0.78
Group One
Dividends Payable [Line Items]
Declaration Date			Jul. 26, 2023
Date Paid (Payable)			Aug. 28, 2023
Shareholder of Record Date			Aug. 14, 2023
Dividend Amount			$ 0.405
Group Two
Dividends Payable [Line Items]
Declaration Date			Apr. 26, 2023
Date Paid (Payable)			May 30, 2023
Shareholder of Record Date			May 15, 2023
Dividend Amount			$ 0.405
Group Three
Dividends Payable [Line Items]
Declaration Date			Jan. 25, 2023
Date Paid (Payable)			Feb. 28, 2023
Shareholder of Record Date			Feb. 14, 2023
Dividend Amount			$ 0.405
Group Four
Dividends Payable [Line Items]
Declaration Date			Oct. 26, 2022
Date Paid (Payable)			Nov. 28, 2022
Shareholder of Record Date			Nov. 14, 2022
Dividend Amount			$ 0.39
Group Five
Dividends Payable [Line Items]
Declaration Date			Jul. 27, 2022
Date Paid (Payable)			Aug. 26, 2022
Shareholder of Record Date			Aug. 12, 2022
Dividend Amount			$ 0.39
Group Six
Dividends Payable [Line Items]
Declaration Date			Apr. 27, 2022
Date Paid (Payable)			May 27, 2022
Shareholder of Record Date			May 13, 2022
Dividend Amount			$ 0.39
Group Seven
Dividends Payable [Line Items]
Declaration Date			Jan. 26, 2022
Date Paid (Payable)			Feb. 25, 2022
Shareholder of Record Date			Feb. 11, 2022
Dividend Amount			$ 0.39

Estimated Percentage of Decoupled Sales (Details)	1 Months Ended	6 Months Ended
Estimated Percentage of Decoupled Sales (Details)	Aug. 31, 2022	Jun. 30, 2023
Operating Revenues [Line Items]
Percentage of total sales volumes revenue subject to RDM	43.00%
Electric \| Before June 1, 2022
Operating Revenues [Line Items]
Percentage of total sales volumes revenue subject to RDM		27.00%
Gas \| Before August 1, 2022
Operating Revenues [Line Items]
Percentage of total sales volumes revenue subject to RDM		11.00%
Gas \| After August 1, 2022
Operating Revenues [Line Items]
Percentage of total sales volumes revenue subject to RDM		43.00%

Retirement Benefit obligations (Tables)

6 Months Ended

Jun. 30, 2023

Key Weighted Average Assumptions Used in Determining Benefit Plan Costs and Obligations

The following table includes the key weighted average assumptions used in determining the Company’s benefit plan costs and obligations:


Used to Determine Plan Costs	2023			2022
Discount Rate		5.25	%		2.85	%
Rate of Compensation Increase		3.00	%		3.00	%
Expected Long-term rate of return on plan assets		7.50	%		7.50	%

Components of Retirement Plan Costs

The following tables provide the components of the Company’s Retirement plan costs ($000’s):


	Pension Plan						PBOP Plan						SERP
For the Three Months Ended June 30,	2023			2022			2023			2022			2023			2022
Service Cost	$	523		$	791		$	373		$	722		$	63		$	68
Interest Cost		1,870			1,371			725			799			188			118
Expected Return on Plan Assets		(2,672	)		(2,720	)		(852	)		(854	)		—			—
Prior Service Cost Amortization		88			89			199			273			14			14
Actuarial Loss Amortization		—			1,377			(366	)		255			—			199
Sub-total		(191	)		908			79			1,195			265			399
Amounts Capitalized and Deferred		366			(309	)		112			(622	)		(82	)		(119	)
Net Periodic Benefit Cost Recognized	$	175		$	599		$	191		$	573		$	183		$	280


	Pension Plan						PBOP Plan						SERP
For the Six Months Ended June 30,	2023			2022			2023			2022			2023			2022
Service Cost	$	1,046		$	1,582		$	746		$	1,444		$	125		$	136
Interest Cost		3,740			2,742			1,450			1,598			377			236
Expected Return on Plan Assets		(5,344	)		(5,440	)		(1,704	)		(1,708	)		—			—
Prior Service Cost Amortization		177			178			397			546			28			28
Actuarial Loss Amortization		—			2,754			(732	)		510			—			399
Sub-total		(381	)		1,816			157			2,390			530			799
Amounts Capitalized and Deferred		864			(464	)		333			(1,133	)		(164	)		(238	)
Net Periodic Benefit Cost Recognized	$	483		$	1,352		$	490		$	1,257		$	366		$	561

Components of Gas Inventory (Detail) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Public Utilities, Inventory [Line Items]
Weighted average cost inventory amount	$ 1.0	$ 1.8	$ 1.0
Natural Gas
Public Utilities, Inventory [Line Items]
Weighted average cost inventory amount	0.6	1.0	0.5
Propane
Public Utilities, Inventory [Line Items]
Weighted average cost inventory amount	0.3	0.4	0.4
Liquefied Natural Gas & Other
Public Utilities, Inventory [Line Items]
Weighted average cost inventory amount	$ 0.1	$ 0.4	$ 0.1

Consolidated Statements Of Earnings (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Operating Revenues
Total Operating Revenues	$ 103.4	$ 98.9	$ 323.6	$ 291.5
Operating Expenses
Operation and Maintenance	18.3	18.4	36.4	36.9
Depreciation and Amortization	16.6	14.8	33.3	30.3
Taxes Other Than Income Taxes	6.8	6.7	14.1	13.5
Total Operating Expenses	91.6	87.0	272.3	243.8
Operating Income	11.8	11.9	51.3	47.7
Interest Expense, Net	7.0	6.3	14.1	12.5
Other (Income) Expense, Net	(0.1)	0.6	(0.1)	1.3
Income Before Income Taxes	4.9	5.0	37.3	33.9
Provision for Income Taxes	0.7	0.1	9.0	7.5
Net Income	$ 4.2	$ 4.9	$ 28.3	$ 26.4
Net Income Per Common Share-Basic	$ 0.25	$ 0.3	$ 1.76	$ 1.65
Net Income Per Common Share-Diluted	$ 0.25	$ 0.3	$ 1.76	$ 1.65
Weighted Average Common Shares Outstanding-Basic	16.0	16.0	16.0	16.0
Weighted Average Common Shares Outstanding-Diluted	16.0	16.0	16.0	16.0
Electric
Operating Revenues
Total Operating Revenues	$ 64.5	$ 54.3	$ 172.7	$ 143.5
Operating Expenses
Cost of Sales	40.3	30.7	121.8	95.3
Gas
Operating Revenues
Total Operating Revenues	38.9	44.6	150.9	148.0
Operating Expenses
Cost of Sales	$ 9.6	$ 16.4	$ 66.7	$ 67.8

Debt and Financing Arrangements

6 Months Ended

Jun. 30, 2023

Debt And Financing Arrangements

Note 4 - Debt AND FINANCING ARRANGEMENTS

Details on long-term debt at June 30, 2023, June 30, 2022 and December 31, 2022 are shown below.


(millions)	June 30,				December 31,
	2023		2022		2022
Unitil Corporation:
3.70% Senior Notes, Due August 1, 2026	$	30.0	$	30.0	$	30.0
3.43% Senior Notes, Due December 18, 2029		30.0		30.0		30.0
Unitil Energy First Mortgage Bonds:
8.49% Senior Secured Notes, Due October 14, 2024		—		1.5		—
6.96% Senior Secured Notes, Due September 1, 2028		12.0		14.0		12.0
8.00% Senior Secured Notes, Due May 1, 2031		12.0		13.5		13.5
6.32% Senior Secured Notes, Due September 15, 2036		15.0		15.0		15.0
3.58% Senior Secured Notes, Due September 15, 2040		27.5		27.5		27.5
4.18% Senior Secured Notes, Due November 30, 2048		30.0		30.0		30.0
Fitchburg:
6.79% Senior Notes, Due October 15, 2025		2.0		6.0		2.0
3.52% Senior Notes, Due November 1, 2027		10.0		10.0		10.0
7.37% Senior Notes, Due January 15, 2029		7.2		8.4		8.4
5.90% Senior Notes, Due December 15, 2030		15.0		15.0		15.0
7.98% Senior Notes, Due June 1, 2031		14.0		14.0		14.0
3.78% Senior Notes, Due September 15, 2040		27.5		27.5		27.5
4.32% Senior Notes, Due November 1, 2047		15.0		15.0		15.0
Northern Utilities:
3.52% Senior Notes, Due November 1, 2027		20.0		20.0		20.0
7.72% Senior Notes, Due December 3, 2038		50.0		50.0		50.0
3.78% Senior Notes, Due September 15, 2040		40.0		40.0		40.0
4.42% Senior Notes, Due October 15, 2044		50.0		50.0		50.0
4.32% Senior Notes, Due November 1, 2047		30.0		30.0		30.0
4.04% Senior Notes, Due September 12, 2049		40.0		40.0		40.0
Granite State:
3.72% Senior Notes, Due November 1, 2027		15.0		15.0		15.0
Unitil Realty Corp.:
2.64% Senior Secured Notes, Due December 18, 2030		4.1		4.4		4.2
Total Long-Term Debt		496.3		506.8		499.1
Less: Unamortized Debt Issuance Costs		3.2		3.5		3.3
Total Long-Term Debt, net of Unamortized Debt Issuance Costs		493.1		503.3		495.8
Less: Current Portion		6.9		8.2		6.7
Total Long-term Debt, Less Current Portion	$	486.2	$	495.1	$	489.1

Fair Value of Long-Term Debt - Currently, the Company believes there is no active market in the Company’s debt securities, which have all been sold through private placements. If there were an active market for the Company’s debt securities, the fair value of the Company’s long-term debt would be estimated based on the quoted market prices for the same or similar issues, or on the current rates offered to the Company for debt of the same remaining maturities. The fair value of the Company’s long-term debt is estimated using Level 2 inputs (valuations based on quoted prices available in active markets for similar assets or liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, inputs other than quoted prices that are directly observable, and inputs derived principally from market data). In estimating the fair value of the Company’s long-term debt, the assumed market yield reflects the Moody’s Baa Utility Bond Average Yield. Costs, including prepayment costs, associated with the early settlement of long-term debt are not taken into consideration in determining fair value.


(millions)	June 30,				December 31,
	2023		2022		2022
Estimated Fair Value of Long-Term Debt	$	446.2	$	477.3	$	455.3

On September 29, 2022, the Company entered into a Third Amended and Restated Credit Agreement with a syndicate of lenders (collectively, the "Credit Facility”), which amended and restated in its entirety the prior credit facility. Unitil may borrow under the Credit Facility until September 29, 2027, subject to two one-year extensions under certain circumstances. The Credit Facility

terminates and all amounts outstanding thereunder are due and payable on September 29, 2027, subject to the potential extension discussed in the prior sentence.

The Credit Facility has a borrowing limit of $200 million, which includes a $25 million sublimit for the issuance of standby letters of credit. Unitil may increase the borrowing limit under the Credit Facility by up to $75 million under certain circumstances. The Credit Facility generally provides Unitil with the ability to elect that borrowings under the Credit Facility bear interest under several options, including a daily fluctuating rate equal to (a) the forward-looking secured overnight financing rate (as administered by the Federal Reserve Bank of New York) term rate with a term equivalent to one month beginning on that date, plus (b) 0.1000%, plus (c) a margin of 1.125% to 1.375% (based on Unitil’s credit rating).

The Company utilizes the Credit Facility for cash management purposes related to its short-term operating activities. Total gross borrowings were $193.6 million for the six months ended June 30, 2023. Total gross repayments were $177.9 million for the six months ended June 30, 2023. The following table details the borrowing limits, amounts outstanding and amounts available under the Credit Facility as of June 30, 2023 and December 31, 2022 and for the prior credit facility as of June 30, 2022:


	Revolving Credit Facility (millions)
	June 30,				December 31,
	2023		2022		2022
Limit	$	200.0	$	120.0	$	200.0
Short-Term Borrowings Outstanding		131.7		46.2		116.0
Available	$	68.3	$	73.8	$	84.0

The Credit Facility contains customary terms and conditions for credit facilities of this type, including affirmative and negative covenants. There are restrictions on, among other things, Unitil’s and its subsidiaries’ ability to incur liens or incur indebtedness, and restrictions on Unitil’s ability to merge or consolidate with another entity or change its line of business. The affirmative and negative covenants under the Credit Facility shall apply to Unitil until the Credit Facility terminates and all amounts borrowed under Credit Facility are paid in full (or, with respect to letters of credit, they are cash-collateralized). The only financial covenant in the Credit Facility provides that Unitil’s Funded Debt to Capitalization (as each term is defined in the Credit Facility) cannot exceed 65% tested on a quarterly basis. At June 30, 2023, June 30, 2022 and December 31, 2022, the Company was in compliance with the covenants contained in the Credit Facility or the prior credit facility, as applicable, in effect on those dates.

The average interest rates on all short-term borrowings and intercompany money pool transactions were 6.3% and 2.1% for the three months ended June 30, 2023 and June 30, 2022, respectively. The average interest rates on all short-term borrowings and intercompany money pool transactions were 6.1% and 1.7% for the six months ended June 30, 2023 and June 30, 2022, respectively. The average interest rate on all short-term borrowings for the twelve months ended December 31, 2022 was 3.3%.

On July 6, 2023, Fitchburg issued $12.0 million of Notes due July 6, 2033 at 5.70% and $13.0 million of Notes due July 6, 2053 at 5.96%. Fitchburg used the net proceeds from these offerings to refinance existing debt and for general corporate purposes. Approximately $0.2 million of costs associated with this issuance will be recorded as a reduction of Long-Term Debt for presentation purposes on the Consolidated Balance Sheet in the third quarter of 2023.

Northern Utilities enters into asset management agreements under which Northern Utilities releases certain gas pipeline and storage assets, sells to an asset manager and subsequently repurchases the gas over the course of the gas heating season at the same price at which it sold the gas to the asset manager. There was $8.7 million of natural gas storage inventory and corresponding obligations at June 30, 2023 related to these asset management agreements. The amount of natural gas inventory released in June 30, 2023, which was payable in July 2023, was less than $0.1 million and was recorded in Accounts Payable at June 30, 2023.

Guarantees

The Company provides limited guarantees on certain energy and gas storage management contracts entered into by the distribution utilities. The Company’s policy is to limit the duration of these guarantees. As of June 30, 2023 there were no guarantees outstanding.

Leases

Unitil’s subsidiaries lease some of their vehicles, machinery and office equipment under both capital and operating lease arrangements.

Total rental expense under operating leases charged to operations for the three months ended June 30, 2023 and June 30, 2022 amounted to $0.5 million and $0.5 million, respectively. Total rental expense under operating leases charged to operations for the six months ended June 30, 2023 and June 30, 2022 amounted to $1.0 million and $0.9 million, respectively.

The balance sheet classification of the Company’s lease obligations was as follows:


	June 30,				December 31,
Lease Obligations (millions)	2023		2022		2022
Operating Lease Obligations:
Other Current Liabilities (current portion)	$	1.7	$	1.5	$	1.5
Other Noncurrent Liabilities (long-term portion)		3.5		2.9		2.8
Total Operating Lease Obligations		5.2		4.4		4.3
Capital Lease Obligations:
Other Current Liabilities (current portion)		0.1		0.1		0.1
Other Noncurrent Liabilities (long-term portion)		0.3		0.1		0.1
Total Capital Lease Obligations		0.4		0.2		0.2
Total Lease Obligations	$	5.6	$	4.6	$	4.5

Cash paid for amounts included in the measurement of operating lease obligations for the six months ended June 30, 2023 and June 30, 2022 was $1.0 million and $0.9 million and was included in Cash Provided by Operating Activities on the Consolidated Statements of Cash Flows.

Assets under capital leases amounted to approximately $0.8 million, $0.7 million and $0.6 million as of June 30, 2023, June 30, 2022 and December 31, 2022, respectively, less accumulated amortization of $0.4 million, $0.4 million and $0.4 million, respectively and are included in Net Utility Plant on the Company’s Consolidated Balance Sheets.


Lease Payments ($000’s)	Operating		Capital
Year Ending December 31,	Leases		Leases
Rest of 2023	$	1,040	$	71
2024		1,761		118
2025		1,189		86
2026		890		74
2027		613		70
2028 - 2032		238		2
Total Payments		5,731		421
Less: Interest		484		24
Amount of Lease Obligations Recorded on Consolidated Balance Sheets	$	5,247	$	397

Operating lease obligations are based on the net present value of the remaining lease payments over the remaining lease term. In determining the present value of lease payments, the Company used the interest rate stated in each lease agreement. As of June 30, 2023, the weighted average remaining lease term is 3.7 years and the weighted average operating discount rate used to determine the operating lease obligations was 4.5%. As of June 30, 2022, the weighted average remaining lease term was 3.3 years and the weighted average operating discount rate used to determine the operating lease obligations was 3.6%.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (h)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 470
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//470/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1B

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1C
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1C

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1E
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1E

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481139/470-20-50-1I

+ Details

Regulatory Matters - Additional Information (Detail) $ in Millions																									1 Months Ended	3 Months Ended
	May 01, 2023 USD ($)	Apr. 15, 2023 USD ($)	Feb. 14, 2023 USD ($)	Dec. 30, 2022 USD ($)	Nov. 02, 2022 USD ($)	Sep. 22, 2022 USD ($)	Aug. 19, 2022 USD ($)	Jul. 28, 2022 USD ($)	Jul. 20, 2022 USD ($)	Jul. 15, 2022 USD ($)	Jun. 08, 2022 USD ($)	May 12, 2022 USD ($)	May 03, 2022 USD ($)	May 01, 2022 USD ($)	Jan. 31, 2022 USD ($)	Nov. 02, 2021 USD ($)	Aug. 24, 2021 USD ($)	Mar. 01, 2021 USD ($)	Nov. 30, 2020 USD ($)	Apr. 01, 2020 USD ($)	Mar. 31, 2020 USD ($)	Feb. 28, 2020 USD ($)	Jul. 31, 2018 MW MWh	Jun. 30, 2017	Mar. 31, 2020 USD ($)	Mar. 31, 2022 USD ($)	Jun. 30, 2027 MW MWh	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Nov. 30, 2022 USD ($)	Oct. 31, 2022 USD ($)	Oct. 07, 2022 USD ($)	May 31, 2022 MW	May 27, 2022 USD ($)	May 07, 2021 MW
Regulatory Asset [Line Items]
Approved annual increase in rates																				$ 3.6	$ 4.6
Increase in annual base rate																				3.60%
Requested annual increase in rates														$ 2.1
Approved annual increase in rates																									$ 3.7
Deferred cost related to exogenous event																												$ 1.1
Budget For EV program				$ 1.0
Program Segment spendings description				The Company may shift spending between program segments and between years over the five-year term of its program, subject to a 15 percent cap. Any spending above the approved EV program budget or above the 15 percent cap for each program segment is not eligible for targeted cost recovery through the GMF
Other Restructuring
Regulatory Asset [Line Items]
Cost recovery period, years																												2 years
Offshore Wind Energy
Regulatory Asset [Line Items]
Power generation facility \| MW																											1,600
Northern Utilities Inc
Regulatory Asset [Line Items]
Percentage of approved return on equity													9.20%
Percentage of approved return on equity, reflecting on equity													52.00%
Percentage of approved return on equity, reflecting on debt													48.00%
Approved annual increase in rates	$ 11.8		$ 1.2								$ 1.6		$ 6.3
Increase in annual base rate	9.40%
Public utilities approved increase amount of annual revenue to recover eligible capital investments								$ 1.3
Northern Utilities Inc \| Settlement Agreement [Member]
Regulatory Asset [Line Items]
Approved annual increase in rates									$ 6.1
Northern Utilities Inc \| Arrearage Management Program [Member]
Regulatory Asset [Line Items]
Expenses associated with the program excluded from the revenue requirement as per order and adjusted increase amount will result in reasonable rates												$ 5.9
Northern Utilities Inc \| New Hampshire
Regulatory Asset [Line Items]
Percentage of approved return on equity										9.30%
Percentage of approved return on equity, reflecting on equity										52.00%
Percentage of approved return on equity, reflecting on debt										48.00%
Threshold amount that will be allowed to adjust distribution rates upward or downward during the term of stay out period										$ 200,000.0
Fitchburg Gas and Electric Light Company
Regulatory Asset [Line Items]
Increase (decrease) in annual revenue					$ 3.1											$ 1.6
Percentage of approved return on equity															9.70%
Percentage of approved return on equity, reflecting on equity															52.45%
Percentage of approved return on equity, reflecting on debt															47.55%
Power generation capacity \| MWh																											9,450,000
Remuneration Percentage				2.25%
Revenue impact threshold															$ 0.1
Fitchburg Gas and Electric Light Company \| Offshore Wind Energy
Regulatory Asset [Line Items]
Power generation capacity \| MW																							400
Remuneration Percentage																							2.75%	2.75%
Fitchburg Gas and Electric Light Company \| Offshore Wind Energy \| Second Solicitation [Member]
Regulatory Asset [Line Items]
Power generation capacity \| MW																																	1,600		1,600
Fitchburg Gas and Electric Light Company \| Qualified Clean Energy
Regulatory Asset [Line Items]
Power generation capacity \| MWh																							9,554,940
Fitchburg Gas Company
Regulatory Asset [Line Items]
Percentage of approved return on equity																						9.70%
Percentage of approved return on equity, reflecting on equity																						52.45%
Percentage of approved return on equity, reflecting on debt																						47.55%
Regulatory assets approved increase in revenue due to be recovered														$ 3.3																	$ 4.5			$ 0.4
Recovery of deferred costs		$ 1.0
Approved annual increase in rates															$ 1.1			$ 0.9
Approved annual increase in rates																										$ 0.9
Apporved annual decrease in rates																										$ 0.2
Revenue impact threshold																						$ 40,000.0
Fitchburg Gas Company \| Track One [Member]
Regulatory Asset [Line Items]
Amount of capital expenditure approved by regulatory authority																																$ 9.3
Fitchburg Gas Company \| Track Two [Member]
Regulatory Asset [Line Items]
Budget for Additional investment																														$ 1.5
Budget for replacement investments																														11.2
Amount of replacement investments approved by regulatory authority																														$ 2.3
Granite State
Regulatory Asset [Line Items]
Increase (decrease) in annual revenue							$ 0.3										$ 0.1		$ 1.3
Spending cap																													$ 14.6
With Effect From First January Two Thousand And Twenty Three [Member]
Regulatory Asset [Line Items]
Public utilities interim increase decrease amount						$ 0.7
With Effect From First March Two Thousand And Twenty Three [Member] \| Fitchburg Gas Company
Regulatory Asset [Line Items]
Public utilities interim increase decrease amount						0.7
Recover Deferred Costs						$ 1.2
Public Infrastructure Offering [Member]
Regulatory Asset [Line Items]
Budget For EV program				$ 0.5
Electric Vehicle Supply Equipment [Member]
Regulatory Asset [Line Items]
Budget For EV program				0.3
Marketing And Outreach [Member]
Regulatory Asset [Line Items]
Budget For EV program				$ 0.2

Retirement Benefit Obligations - Additional Information (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, assumed health care cost trend rate, description	The health care cost trend rate used to determine benefit plan costs for 2023 for pre-65 retirees is 8.00%, with an ultimate rate of 4.50% in 2030, and for post-65 retirees, the health care cost trend rate is 6.25%, with an ultimate rate of 4.50% in 2030. The health care cost trend rate used to determine benefit plan costs for 2022 for both pre-65 and post-65 retirees is 6.20%, with an ultimate rate 4.50% in 2029.
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 1.9
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	0.6
Supplemental Employee Retirement Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Benefit payments under SERP Plan	0.3
Expected additional benefit payments for the remainder of 2020	$ 0.3
Pre-65 retirees
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate, assumed	8.00%
Health care cost trend rate, ultimate rate	4.50%
Health care cost trend rate, ultimate rate in year	2030
Post-65 retirees
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate, assumed	6.25%	6.20%
Health care cost trend rate, ultimate rate	4.50%	4.50%
Health care cost trend rate, ultimate rate in year	2030	2029

Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2023

Components of Gas and Electric Operating Revenue

In the following tables, revenue is classified by the types of goods/services rendered and market/customer type.


	Three Months Ended June 30, 2023
Electric and Gas Operating Revenues (millions):	Electric			Gas			Total
Billed and Unbilled Revenue:
Residential	$	39.8		$	17.9		$	57.7
Commercial and Industrial		28.1			26.4			54.5
Other		1.9			1.0			2.9
Total Billed and Unbilled Revenue		69.8			45.3			115.1
Rate Adjustment Mechanism Revenue		(5.3	)		(6.4	)		(11.7	)
Total Electric and Gas Operating Revenues	$	64.5		$	38.9		$	103.4


	Three Months Ended June 30, 2022
Electric and Gas Operating Revenues (millions):	Electric			Gas			Total
Billed and Unbilled Revenue:
Residential	$	33.8		$	18.1		$	51.9
Commercial and Industrial		25.7			28.0			53.7
Other		4.6			3.5			8.1
Total Billed and Unbilled Revenue		64.1			49.6			113.7
Rate Adjustment Mechanism Revenue		(9.8	)		(5.0	)		(14.8	)
Total Electric and Gas Operating Revenues	$	54.3		$	44.6		$	98.9


	Six Months Ended June 30, 2023
Electric and Gas Operating Revenues (millions):	Electric		Gas			Total
Billed and Unbilled Revenue:
Residential	$	99.9	$	67.0		$	166.9
Commercial and Industrial		62.9		95.6			158.5
Other		4.6		4.6			9.2
Total Billed and Unbilled Revenue		167.4		167.2			334.6
Rate Adjustment Mechanism Revenue		5.3		(16.3	)		(11.0	)
Total Electric and Gas Operating Revenues	$	172.7	$	150.9		$	323.6


	Six Months Ended June 30, 2022
Electric and Gas Operating Revenues (millions):	Electric			Gas			Total
Billed and Unbilled Revenue:
Residential	$	83.0		$	63.6		$	146.6
Commercial and Industrial		56.7			92.7			149.4
Other		9.1			7.0			16.1
Total Billed and Unbilled Revenue		148.8			163.3			312.1
Rate Adjustment Mechanism Revenue		(5.3	)		(15.3	)		(20.6	)
Total Electric and Gas Operating Revenues	$	143.5		$	148.0		$	291.5

Estimated Percentage of Decoupled Sales

The following table shows the estimated percentages of electric and gas sales that are subject to revenue decoupling for the periods presented.


Revenue Decoupling
Estimated Percentage of Decoupled Sales
For Periods Presented
Electric
Before June 1, 2022	27%
After June 1, 2022	Substantially All
Gas
Before August 1, 2022	11%
After August 1, 2022	43%

Allowance for Doubtful Accounts Included in Accounts Receivable Net

The Allowance for Doubtful Accounts as of June 30, 2023, June 30, 2022 and December 31, 2022, was as follows:


	June 30,				December 31,
(millions)	2023		2022		2022
Allowance for Doubtful Accounts	$	2.2	$	2.7	$	2.6

Components of Accrued Revenue

The following table shows the components of Accrued Revenue as of June 30, 2023, June 30, 2022 and December 31, 2022.


	June 30,				December 31,
Accrued Revenue (millions)	2023		2022		2022
Regulatory Assets – Current	$	56.8	$	41.4	$	66.5
Unbilled Revenues, net		3.6		4.2		6.3
Total Accrued Revenue	$	60.4	$	45.6	$	72.8

Components of Exchange Gas Receivable

The following table shows the components of Exchange Gas Receivable as of June 30, 2023, June 30, 2022 and December 31, 2022.


	June 30,				December 31,
Exchange Gas Receivable (millions)	2023		2022		2022
Northern Utilities	$	8.7	$	12.5	$	16.3
Fitchburg		0.7		0.9		1.7
Total Exchange Gas Receivable	$	9.4	$	13.4	$	18.0

Components of Gas Inventory

The following table shows the components of Gas Inventory as of June 30, 2023, June 30, 2022 and December 31, 2022.


	June 30,				December 31,
Gas Inventory (millions)	2023		2022		2022
Natural Gas	$	0.6	$	0.5	$	1.0
Propane		0.3		0.4		0.4
Liquefied Natural Gas & Other		0.1		0.1		0.4
Total Gas Inventory	$	1.0	$	1.0	$	1.8

Regulatory Assets

The Company currently receives recovery in rates or expects to receive recovery of these hardship accounts in future rate cases.


	June 30,				December 31,
Regulatory Assets consist of the following (millions)	2023		2022		2022
Retirement Benefits	$	27.2	$	86.9	$	29.1
Energy Supply and Other Rate Adjustment Mechanisms		54.0		38.2		63.0
Deferred Storm Charges		8.5		2.9		3.4
Environmental		6.1		4.5		5.9
Income Taxes		1.5		2.2		1.8
Other Deferred Charges		11.0		13.3		11.1
Total Regulatory Assets		108.3		148.0		114.3
Less: Current Portion of Regulatory Assets(1)		56.8		41.4		66.5
Regulatory Assets – noncurrent	$	51.5	$	106.6	$	47.8

Reflects amounts included in the Accrued Revenue on the Company’s Consolidated Balance Sheets.

Regulatory Liabilities


	June 30,				December 31,
Regulatory Liabilities consist of the following (millions)	2023		2022		2022
Income Taxes (Note 8)	$	39.6	$	42.6	$	41.0
Rate Adjustment Mechanisms		14.3		22.2		10.9
Total Regulatory Liabilities		53.9		64.8		51.9
Less: Current Portion of Regulatory Liabilities		18.4		25.9		15.0
Regulatory Liabilities – noncurrent	$	35.5	$	38.9	$	36.9

Fair Value of Marketable Securities

Changes in the fair value of these investments are recorded in Other Expense, Net.


	June 30,				December 31,
Fair Value of Marketable Securities (millions)	2023		2022		2022
Money Market Funds	$	5.8	$	5.4	$	5.8
Total Marketable Securities	$	5.8	$	5.4	$	5.8

Components of Energy Supply Obligations

The following discussion and table summarize the nature and amounts of the items recorded as Energy Supply Obligations (current portion) and Other Noncurrent Liabilities (noncurrent portion) on the Company’s Consolidated Balance Sheets.


	June 30,				December 31,
Energy Supply Obligations (millions)	2023		2022		2022
Current:
Exchange Gas Obligation	$	8.7	$	12.5	$	16.3
Renewable Energy Portfolio Standards		5.2		4.1		7.8
Total Energy Supply Obligations	$	13.9	$	16.6	$	24.1

Deferred Compensation Plan [Member]

Fair Value of Marketable Securities

Changes in the fair value of these investments are recorded in Other Expense, Net.


	June 30,				December 31,
Fair Value of Marketable Securities (millions)	2023		2022		2022
Equity Funds	$	1.0	$	0.4	$	0.5
Money Market Funds		0.1		0.4		0.1
Total Marketable Securities	$	1.1	$	0.8	$	0.6

Debt and Financing Arrangements - Borrowing Limits Amounts Outstanding and Amounts Available under Revolving Credit Facility (Detail) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Debt Instrument [Line Items]
Short-Term Borrowings Outstanding	$ 131.7	$ 116.0	$ 46.2
Revolving Credit Facility
Debt Instrument [Line Items]
Revolving credit facility, limit	200.0	200.0	120.0
Short-Term Borrowings Outstanding	131.7	116.0	46.2
Available revolving credit facility	$ 68.3	$ 84.0	$ 73.8

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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+ Details

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions	1 Months Ended	6 Months Ended
	Aug. 31, 2022	Jun. 30, 2023 USD ($) Subsidiary mi	Jul. 06, 2023 USD ($)	Dec. 31, 2022 USD ($)	Jun. 30, 2022 USD ($)
Significant Accounting Policies [Line Items]
Number of Subsidiaries \| Entity \| Subsidiary		3
Length of Pipeline \| mi		86
Percentage of total sales volumes revenue subject to RDM	43.00%
Cost of removal obligation		$ 123.2		$ 116.1	$ 112.4
Investments in trading securities		5.8		5.8	5.4
Allowance for doubtful accounts		2.2		2.6	2.7
Regulatory assets		108.3		114.3	148.0
Other Deferred Charges [Member]
Significant Accounting Policies [Line Items]
Regulatory assets		11.0		11.1	13.3
Unbilled Revenues [Member]
Significant Accounting Policies [Line Items]
Allowance for doubtful accounts		0.1		0.1	0.1
Accounts Receivable [Member]
Significant Accounting Policies [Line Items]
Allowance for doubtful accounts		$ 2.2		2.5	2.6
Utilities
Significant Accounting Policies [Line Items]
Number of Subsidiaries \| Entity \| Subsidiary		3
Unitil Service; Unitil Realty; and Unitil Resources
Significant Accounting Policies [Line Items]
Number of Subsidiaries \| Entity \| Subsidiary		3
Fitchburg Gas And Electric Light Company [Member] \| Other Deferred Charges [Member] \| Electric and Gas Division [Member]
Significant Accounting Policies [Line Items]
Hardship accounts in regulatory assets		$ 6.0		5.8	7.6
Subsequent Event [Member]
Significant Accounting Policies [Line Items]
Debt issuance principal amount			$ 25.0
Environmental and Rate Case Costs and Other Expenditures \| Recovered over the next seven years
Significant Accounting Policies [Line Items]
Regulatory assets		5.5
ISO-NE Obligations
Significant Accounting Policies [Line Items]
Cash Deposits		$ 3.3		6.0	1.7
Maximum
Significant Accounting Policies [Line Items]
Lease term		12 months
Deferred Compensation Plan [Member]
Significant Accounting Policies [Line Items]
Investments in trading securities		$ 1.1		$ 0.6	$ 0.8

Debt and Financing Arrangements - Estimated Fair Value of Long Term Debt (Detail) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Debt Instrument [Line Items]
Estimated Fair Value of Long-Term Debt	$ 446.2	$ 455.3	$ 477.3

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

+ Details

Regulatory Matters

6 Months Ended

Jun. 30, 2023

Regulatory Matters

note 6 - REgulatory Matters

Unitil’s Regulatory matters are described in Note 8 to the Financial Statements in Item 8 of Part II of Unitil Corporation’s Form 10-K for December 31, 2022 as filed with the Securities and Exchange Commission on february 14, 2023.

Rate Case Activity

Northern Utilities - Base Rates - Maine - On May 1, 2023, Northern Utilities filed a rate case with the MPUC to increase its base distribution rates by $11.8 million, a 9.4% increase over the Company’s test year operating revenue. The filing is based on information for 12 months ending December 31, 2022 incorporating a forward-looking analysis of revenues, expenses, and spending through the rate year (February 1, 2024 through January 31, 2025). The last approved base revenue increase was $3.6 million, a 3.6% increase over the Company’s test year operating revenue, effective April 1, 2020.

Northern Utilities - Targeted Infrastructure Replacement Adjustment (TIRA) - Maine - The settlement in Northern Utilities’ Maine division’s 2013 rate case authorized the Company to implement a TIRA rate mechanism to adjust base distribution rates annually to recover the revenue requirements associated with targeted investments in gas distribution system infrastructure replacement and upgrade projects, including the Company’s Cast Iron Replacement Program (CIRP). In its Final Order issued on February 28, 2018 for Northern Utilities’ 2017 base rate case, the MPUC approved an extension of the TIRA mechanism for an additional eight-year period, which will allow for annual rate adjustments through the end of the CIRP program. The Company’s most recent request under the TIRA mechanism, to increase annual base rates by $2.1 million for 2022 eligible facilities, was filed with the MPUC on February 28, 2023. On April 26, 2023, the MPUC issued an order approving the filing, for rates effective May 1, 2023.

Northern Utilities - Base Rates - New Hampshire - On July 20, 2022, the NHPUC issued an Order in the distribution base rate case filed with the NHPUC on August 2, 2021 by Northern Utilities. The Order approves a comprehensive Settlement Agreement between the Company, the New Hampshire Department of Energy (DOE), and the Office of the Consumer Advocate (OCA). As provided in

the Settlement Agreement, in addition to authorizing an increase to permanent distribution rates of $6.1 million, effective August 1, 2022, the Order (1) approves a revenue decoupling mechanism and (2) allows for a step adjustment effective September 1, 2022 covering the additional revenue requirement resulting from changes in Net Plant in Service associated with non-growth investments for the period January 1, 2021, through December 31, 2021. This distribution base rate case reflects the Company’s operating costs and investments in utility plant for a test year ended December 31, 2020 as adjusted for known and measurable changes. The Order provides for a return on equity of 9.3% and a capital structure reflecting 52% equity and 48% long-term debt. In light of the Step Adjustment, the Company shall not file a distribution rate case with the Commission before January 1, 2024 (the Stay-Out Period). However, during the term of the Stay-Out Period, the Company will be allowed to adjust distribution rates upward or downward resulting from a singular (not collective) exogenous event that exceeds $200,000. The increase in permanent rates was reconciled back to October 1, 2021, the effective date of temporary rates previously approved in this docket. On June 8, 2022, the Company filed for its step increase of approximately $1.6 million of annual revenue, for rates effective as of September 1, 2022, to recover eligible 2021 capital investments. On August 31, 2022, the NHPUC approved the Company’s filing. Under the terms of the Settlement Agreement, parties agreed that the Company shall recover revenues associated with the full rate year (August 1, 2022 – July 31, 2023) over an eleven-month period beginning September 1, 2022 and ending July 31, 2023. On May 5, 2023, the Company made a compliance filing to adjust base distribution rates downward to reflect a 12-month recovery period effective August 1, 2023. On July 13, 2023, the NHPUC approved the Company’s compliance filing.

Unitil Energy - Base Rates - On May 3, 2022, the NHPUC issued an Order in the distribution base rate case filed with the NHPUC on April 2, 2021 by Unitil Energy. The Order approves, in part, a comprehensive Settlement Agreement between the Company, the New Hampshire DOE, the OCA, the New Hampshire Department of Environmental Services, Clean Energy New Hampshire, and ChargePoint, Inc. In addition to authorizing an increase to permanent distribution rates of $6.3 million, effective June 1, 2022, the Order approves the following components of the Settlement Agreement: (1) a multi-year rate plan, (2) a revenue decoupling mechanism, (3) time-of-use rates, (4) resiliency programs to support the Company’s commitment to reliability, and (5) other rate design and tariff changes. On May 10, 2022, the Company filed a request for clarification with the NHPUC to clarify that the authorized revenue requirement should exclude expenses related to the Company’s proposed Arrearage Management Program (AMP), which was not approved in the Order. On May 12, 2022, the Commission issued an Order, which clarified that because the Company will not incur the expenses associated with the AMP, those costs should be removed from the revenue requirement, and that the adjusted increase of $5.9 million will result in reasonable rates. The increase in permanent rates was reconciled back to June 1, 2021, the effective date of temporary rates previously approved in this docket. This distribution base rate case reflects the Company’s operating costs and investments in utility plant for a test year ended December 31, 2020 as adjusted for known and measurable changes. The Order provides for a return on equity of 9.2% and a capital structure reflecting 52% equity and 48% long-term debt. On July 28, 2022, the NHPUC approved, subject to reconciliation, the Company’s first step increase of approximately $1.3 million of annual revenue to recover eligible 2021 capital investments, effective August 1, 2022. On May 31, 2023, the NHPUC approved , the Company’s second and final step adjustment increase of approximately $1.2 million to recover eligible 2022 capital investments, effective June 1, 2023.

Fitchburg - Base Rates - Electric- Fitchburg’s base rates are decoupled and subject to an annual revenue decoupling adjustment mechanism, which includes a cap on the amount that rates may be increased in any year. In addition, Fitchburg has an annual capital cost recovery mechanism to recover the revenue requirement associated with certain capital additions. On November 2, 2021, Fitchburg filed its cumulative revenue requirement of $1.6 million associated with its 2019 and 2020 capital expenditures. The MDPU allowed the associated rate increase to become effective on January 1, 2022, subject to further investigation and reconciliation. On June 24, 2022, the MDPU issued an Order approving the Company’s filing. On November 2, 2022, Fitchburg filed its cumulative revenue requirement of $3.1 million associated with its 2019-2021 capital expenditures. The MDPU allowed the associated rate increase to become effective on January 1, 2023, subject to further investigation and reconciliation. On July 26, 2023, the MDPU issued an Order approving the Company's filing.

On April 17, 2020, the MDPU approved a settlement agreement entered into by the Company and the Massachusetts Office of the Attorney General providing for a distribution increase of $1.1 million, effective November 1, 2020. The Company’s subsequent Compliance Filing reflected an adjusted distribution increase of $0.9 million, a decrease of $0.2 million from the original settlement amount due to the finalization of actual rate case expenses. On May 21, 2020, the MDPU approved the Company’s Compliance Filing. The agreement provides for a Return on Equity of 9.7% and a capital structure reflecting 52.45% equity and 47.55% long-term debt. Under the agreement, the Company will not increase or redesign base distribution rates to become effective prior to November 1, 2023, though the Company may seek cost recovery for certain exogenous events that meet a revenue threshold of $0.1 million. The agreement also provides for the implementation of a major storm reserve fund, whereby the Company may recover the costs of restoration for qualifying storm events. In addition, the agreement provides for the extension of the annual capital cost recovery mechanism, modified to allow the recovery of property tax on the cumulative net capital expenditures.

On September 22, 2022, Fitchburg filed a petition with the MDPU to adjust its base distribution rates by $0.7 million effective January 1, 2023 to recover costs due to the exogenous event described below. The filing also includes a request to recover the exogenous costs

incurred from July 2021 through December 2022 through a reconciling mechanism over a 24 month period, beginning January 1, 2023. The Massachusetts Department of Revenue has determined that the “net book value” or “NBV” of utility plant is no longer the basis of valuation for utility property. Most of the municipalities that levy property taxes on Fitchburg have adopted a hybrid valuation approach that increases property tax expense over and above what it would be if NBV was used as the basis of valuation. The change in valuation is a regulatory change that is outside the Company’s control and it uniquely affects the electric and gas industries, thus it is an exogenous event. On December 30, 2022, the MDPU approved the Company’s request to adjust its base distribution rates effective January 1, 2023 and to recover deferred costs of $1.1 million incurred from July 2021 through December 2022 through a reconciling mechanism over a 24 month period, also beginning January 1, 2023.

On June 30, 2023, Fitchburg filed a notice of intent to file a base rate case with the MDPU on or after July 31, 2023 to implement a general increase in rates and making other changes effective July 1, 2024. Under MDPU precedent, a utility company is required to provide no less than a 30 day advance notice of its intent to file for a base rate increase.

Fitchburg - Base Rates - Gas - Pursuant to its revenue decoupling adjustment clause tariff, as approved in its last base rate case, the Company is allowed to modify, on a semi-annual basis, its base distribution rates to an established revenue per customer target in order to mitigate economic, weather, and energy efficiency effects to the Company’s revenues. The MDPU consistently has found the Company’s filings are in accord with its approved tariffs, applicable law and precedent, and that they result in just and reasonable rates.

On February 28, 2020, the MDPU approved a settlement agreement between the Company and the Massachusetts Office of the Attorney General. The agreement provides for an annual distribution revenue increase of $4.6 million to be phased in over two years: (1) an increase of $3.7 million, which became effective on March 1, 2020; and (2) an increase of $0.9 million, which became effective on March 1, 2021. Under the agreement, the Company will not increase or redesign base distribution rates to become effective prior to March 1, 2023, though the Company may seek cost recovery for certain exogenous events that meet a revenue effect threshold of $40,000. The agreement provides for a Return on Equity of 9.7% and a capital structure reflecting 52.45% equity and 47.55% long-term debt. In its September 22, 2022 exogenous cost filing as discussed above, the Company also requested to adjust its gas base distribution rates by $0.7 million effective March 1, 2023 to recover these exogenous costs. The filing also includes a request to recover the exogenous costs incurred from July 2021 through February 2023 through a reconciling mechanism over a 24 month period, beginning March 1, 2023. On December 30, 2022, the MDPU approved the Company’s request to adjust its base distribution rates effective March 1, 2023 and to recover deferred costs of $1.2 million incurred from July 2021 through February 2023 through a reconciling mechanism over a 24 month period, also beginning March 1, 2023.

Fitchburg - Gas System Enhancement Program - Pursuant to statute and MDPU order, Fitchburg has an approved Gas System Enhancement Plan tariff through which it may recover certain gas infrastructure replacement and safety related investment costs, subject to an annual cap. Under the plan, the Company is required to make two annual filings with the MDPU: a forward-looking filing for the subsequent construction year, to be filed on or before October 31; and a filing, submitted on or before May 1, of final project documentation for projects completed during the prior year, demonstrating substantial compliance with its plan in effect for that year and showing that project costs were reasonably and prudently incurred. Fitchburg’s forward-looking cumulative revenue requirement filing submitted on October 29, 2021 requested recovery of approximately $3.3 million, and received final approval on April 28, 2022, effective May 1, 2022. The Company’s most recent forward-looking cumulative revenue requirement filing, filed on October 31, 2022, requested recovery of approximately $4.5 million. On April 28, 2023, the MDPU issued an order approving this filing for rates effective May 1, 2023. The Company considers these to be routine regulatory proceedings, and there are no material issues outstanding.

Granite State - Base Rates - On November 30, 2020, the FERC approved Granite State’s filing of an uncontested rate settlement which provides for an increase in annual revenues of approximately $1.3 million, effective November 1, 2020. The Settlement Agreement permits the filing of limited Section 4 rate adjustments for capital cost projects eligible for cost recovery in 2021, 2022, and 2023, and sets forth an overall investment cap of approximately $14.6 million on the capital cost recoverable under such filings during the term of the Settlement. Under the Settlement Agreement, Granite may not file a new general rate case earlier than April 30, 2024 with rates to be effective no earlier than November 1, 2024 based on a test year ending no earlier than December 31, 2023.

On August 24, 2021, the FERC accepted Granite State’s first limited Section 4 rate adjustment pursuant to the Settlement Agreement, for an annual revenue increase of $0.1 million, effective September 1, 2021. On August 19, 2022, the FERC accepted Granite State’s second limited Section 4 rate adjustment pursuant to the Settlement Agreement, for an annual revenue increase of $0.3 million,

effective September 1, 2022. On July 27, 2023, Granite State filed its third and final limited Section 4 rate adjustment pursuant to the Settlement Agreement, for an annual revenue increase of $1.0 million, effective September 1, 2023. This matter remains pending.

Other Matters

Unitil Energy - Proposal to Construct Utility-Scale Solar Facility - On October 31, 2022, Unitil Energy submitted a petition to the NHPUC for review of Unitil Energy’s proposal to construct, own, and operate a 4.99 MW utility-scale photovoltaic generating facility, which was subsequently revised to a 4.88 MW facility. The Company had requested a finding from the NHPUC within six months of the filing date that the project, as proposed, is in the public interest. On May 1, 2023, the NHPUC issued an Order approving the Company's petition.

Fitchburg - Grid Modernization - On July 1, 2021, Fitchburg submitted its Grid Modernization Plan (GMP) to the MDPU. The GMP includes a five-year strategic plan, including a plan for the full deployment of advanced metering functionality, and a four-year short-term investment plan, which focuses on foundational investments to facilitate the interconnection and integration of distributed energy resources, optimizing system performance through command and control and self-healing measures, and optimizing system demand by facilitating consumer price-responsiveness. On October 7, 2022, the MDPU issued a “Track 1” Order approving a budget cap of $9.3 million through 2025 for previously deployed or preauthorized grid modernization investments. On November 30, 2022, the MDPU issued its “Track 2” Order addressing new technologies and Advanced Metering Infrastructure (AMI) proposals. The MDPU preauthorizes a four-year $1.5 million budget for Fitchburg’s additional grid-facing investments. Any spending over the total budget cap is not eligible for targeted cost recovery through its Grid Modernization Factor (GMF), and instead, may be recovered by the Company in a base distribution rate proceeding subsequent to a prudency finding by the MDPU in a GMF filing or term review Order. The MDPU also preauthorized the Company’s AMI meter replacement investments, with a budget of $11.2 million through 2025. Additionally, the MDPU provided preliminary approval for the Company’s customer engagement and experience and data sharing platform investments, with a combined budget of $2.3 million through 2025. The Company may recover eligible costs incurred for preauthorized grid-facing investments and customer-facing investments that will be made during the 2022-2025 GMP term through the GMFs, subject to certain modifications to the Company’s GMF tariff and a final prudence review. On March 31, 2023, the Company submitted an AMI opt-out tariff with full support of proposed opt-out fees in compliance with the Track 2 Order. The MDPU approved the tariff on April 7, 2023.

On April 24, 2023, Fitchburg submitted its 2022 Grid Modernization Plan Annual Report to the MDPU. On May 31, 2023, the MDPU issued an Order on Fitchburg’s 2023 GMF filing, allowing proposed rates to take effect on June 1, 2023 subject to the further investigation and reconciliation.

Fitchburg - Grid Modernization Cost Recovery Factor - On April 15, 2022, Fitchburg filed its GMF rate adjustment and reconciliation filing pursuant to the Company’s GMF Tariff, for recovery of the costs incurred as a result of implementing the Company’s 2018-2021 GMP, previously approved by the MDPU on February 7, 2019. The proposed GMF of $0.4 million was approved on May 27, 2022, effective June 1, 2022, subject to further investigation and reconciliation. On April 15, 2023, Fitchburg filed its GMF rate adjustment and reconciliation filing for recovery of the costs incurred as a result of implementing the Company’s 2022-2025 GMP, approved by the MDPU in Orders dated October 7, 2022 and November 30, 2022. On May 31, 2023, the MDPU approved, subject to further investigation and reconciliation, the cumulative recovery of $1.0 million associated with the Company’s 2022 revenue requirement, effective June 1, 2023.

Fitchburg - Investigation into the role of gas LDCs to achieve Commonwealth 2050 climate goals -The MDPU has opened an investigation to examine the role of Massachusetts gas local distribution companies (LDCs) in helping the Commonwealth achieve its 2050 climate goal of net-zero greenhouse gas (GHG) emissions. In its Order opening the inquiry, the MDPU stated it is required to consider new policies and structures as the Commonwealth reduces reliance on fossil fuels, including natural gas, which may require LDCs to make significant changes to their planning processes and business models. The LDCs, including Fitchburg, engaged an independent consultant to conduct a study and prepare a report (Consultant Report), including a detailed study of each LDC, that analyzes the feasibility of all identified pathways to help the Commonwealth achieve its net-zero GHG goal. The study includes an examination of the potential pathways identified in the 2050 Decarbonization Roadmap developed by the MA Executive Office of Energy and Environmental Affairs, in consultation with the Massachusetts Department of Environmental Protection and the Massachusetts Department of Energy Resources (DOER). Following an active stakeholder process, on March 18, 2022, Consultant Reports on decarbonization pathways, regulatory designs and stakeholder engagement were submitted to the MDPU. Also on March 18, 2022, the LDCs, including Fitchburg, submitted proposals to the MDPU that include the LDCs’ recommendations and plans for helping the Commonwealth achieve its 2050 climate goals, supported by the Consultant Reports. The MDPU held a technical session on the Consultant Report on March 30, 2022 and a technical session on the LDC proposals on April 15, 2022. Discovery by the MDPU is complete, and the LDCs responded to stakeholder comments on July 29, 2022. Final comments from stakeholders replying to the LDCs’ comments and making any other final remarks for the MDPU’s consideration were filed on October 14, 2022.

Fitchburg – Electric Vehicle (EV) Proceeding – On December 30, 2022, the MDPU issued an order approving Fitchburg’s five-year EV program with a $1.0 million budget consisting of: (1) public infrastructure offering ($0.5 million); (2) Electric Vehicle Supply Equipment (EVSE) incentives for residential segment ($0.3 million); and (3) marketing and outreach ($0.2 million). The Company may shift spending between program segments and between years over the five-year term of its program, subject to a 15 percent cap. Any spending above the approved EV program budget or above the 15 percent cap for each program segment is not eligible for targeted cost recovery through the GMF and, instead, may be recovered in a base distribution rate proceeding subsequent to a prudency finding by the MDPU. Further, the MDPU has convened an EV stakeholder process to finalize EV program performance metrics. On April 3, 2023, the electric companies filed comments on the MDPU’s proposed metrics. Once performance metrics are finalized, the MDPU will require the electric companies to develop a joint state-wide program evaluation plan for MDPU approval and stakeholder input and will determine next steps at that time. The MDPU directs the Companies to submit annual reports that document their performance and these reports will be due on or before May 15th of each year. The first EV annual report is due May 15, 2024. The Company shall file annual rate adjustment and reconciliation filings on or before April 15, with rates effective June 1. The MDPU accepted the Company’s Demand Charge Alternative proposal and directed implementation within six months. The Demand Charge Alternative is offered for a ten-year period beginning July 1, 2023 with tiered rates to separately-metered EV general delivery service customers. The MDPU accepted the Company’s proposed residential EV TOU rate, effective April 1, 2023.

Northern Utilities / Granite State - Firm Capacity Contract - Northern Utilities relies on the transportation of gas supply over its affiliate Granite State pipeline to serve its customers in the Maine and New Hampshire service territories. Granite State facilitates critical upstream interconnections with interstate pipelines and third party suppliers essential to Northern Utilities’ service to its customers. Northern Utilities reserves firm capacity through a contract with Granite State, which is renewed annually. Pursuant to statutory requirements in Maine and orders of the MPUC, Northern Utilities submits an annual informational report requesting approval of a one-year extension of its 12-month contract for firm pipeline capacity reservation, with an evergreen provision and three-month termination notification requirement. On April 3, 2023, Northern Utilities submitted an annual informational report requesting approval on a one-year extension for the period of November 1, 2023 through October 31, 2024. The MPUC issued an Order on June 13, 2023 approving the one-year extension.

Reconciliation Filings - Fitchburg, Unitil Energy and Northern Utilities each have a number of regulatory reconciling accounts that require annual or semi-annual filings with the MDPU, NHPUC and MPUC, respectively, to reconcile costs and revenues, and to seek approval of any rate changes. These filings include: annual electric reconciliation filings by Fitchburg and Unitil Energy for a number of items, including default service, stranded cost changes and transmission charges; costs associated with energy efficiency programs in New Hampshire and Massachusetts, as directed by the NHPUC and MDPU; recovery of the ongoing costs of storm repairs incurred by Unitil Energy; and the actual wholesale energy costs for electric power and gas incurred by each of the three companies. Fitchburg, Unitil Energy and Northern Utilities have been, and remain in full compliance with all directives and orders regarding these filings. The Company considers these to be routine regulatory proceedings, and there are no material issues outstanding.

Fitchburg - Massachusetts Request for Proposals (RFPs) - Pursuant to Section 83C of “An Act to Promote Energy Diversity” (2016) (the Act), the Massachusetts electric distribution companies (EDCs), including Fitchburg, are required to jointly procure a total of 1,600 MW of offshore wind by June 30, 2027. Under Section 83D of the Act, the EDCs are required to jointly seek proposals for cost-effective clean energy (hydroelectric, solar and land-based wind) long-term contracts via one or more staggered solicitations for a total of 9,450,000 megawatt-hours (MWh) by December 31, 2022. Fitchburg’s pro rata share of these contracts is approximately 1%.

The EDCs issued the RFP for Section 83D Long-Term Contracts in March 2017, and power purchase agreements (PPAs) for 9,554,940 MWh of hydroelectric generation and associated environmental attributes from Hydro-Quebec Energy Services (U.S.), Inc. were filed in July 2018 for approval by the MDPU. On June 25, 2019, the MDPU approved the PPAs, including the EDCs’ proposal to sell the energy procured under the contract into the ISO-NE wholesale market and to credit or charge the difference between the contract costs and the ISO-NE market costs to customers. The MDPU also approved the EDCs’ request for remuneration equal to 2.75% of the contract payments, as well as the EDCs’ proposal to recover costs associated with the contracts. On January 13, 2023, NECEC Transmission LLC (“NECEC”), the company with which Fitchburg and the other EDCs entered into transmission service agreements (“TSAs”) for the delivery of the Hydro-Quebec energy, provided a letter to the EDCs purporting to give notice of a “change in applicable law” related to a Maine ballot initiative and requesting a negotiated amendment to the TSAs. On June 27, 2023, NECEC sent a letter to the EDCs seeking schedule relief also in accordance with their “change in law” determination. The EDCs are evaluating NECEC’s requests.

The EDCs issued an initial RFP pursuant to Section 83C in June 2017. On July 23, 2018, the EDCs, filed two long-term contracts with Vineyard Wind, each for 400 MW of offshore wind energy generation, for approval by the MDPU. On April 12, 2019, the MDPU approved the offshore wind energy generation PPAs, including the EDCs’ proposal to sell the energy procured under the contract into the ISO-NE wholesale market and to credit or charge the difference between the contract costs and the ISO-NE market costs to customers. The EDCs issued a second RFP pursuant to Section 83C to procure an additional 800 MW of offshore wind energy generation in May 2019. The EDCs filed for approval of two PPAs with Mayflower Wind Energy LLC, each for 400 MW of offshore

wind energy generation, in February 10, 2020. On November 5, 2020, the MDPU approved the second RFP PPAs. In both cases, the MDPU approved the EDCs’ request for remuneration equal to 2.75% of the contract payments, as well as the EDCs’ proposal to recover costs associated with the contracts.

In accordance with “An Act to Advance Clean Energy” (2018) the Massachusetts Department of Energy Resources (DOER) recommended that the EDCs solicit up to 1,600 MW in additional offshore wind in 2022 and 2024. On May 7, 2021, the EDCs issued a third RFP for up to an additional 1,600 MW of off shore wind generation. On May 25, 2022, the EDCs sought approval of PPAs with Commonwealth Wind for 1,200 MW and with South Coast Wind (formerly Mayflower Wind) for 400 MW. On December 16, 2022, Commonwealth Wind filed a motion requesting that the MDPU dismiss proceedings related to the approval of its contract, arguing that, due to various economic conditions, its contracts with the EDCs would no longer facilitate the financing of offshore wind energy generation. On December 30, 2022, the MDPU denied Commonwealth’s motion and approved the PPAs. The MDPU also approved the EDCs’ request for remuneration equal to 2.25% as reasonable and in the public interest. On January 19, 2023, Commonwealth Wind filed a Petition for Appeal with the Massachusetts Supreme Judicial Court seeking to set aside and vacate the MDPU’s Order approving the PPAs. This appeal is pending. On the same day, Mayflower Wind submitted a motion to the MDPU requesting that it extend the period for filing an appeal (which otherwise expired on January 19, 2023) by five business days from the date that the motion is approved. The MDPU denied Mayflower Wind’s motion. The EDCs have negotiated termination agreements with Commonwealth Wind and submitted the agreements to the MDPU for approval on July 13, 2023.

In 2021, the MA legislature increased the total solicitation target (including future solicitations) for offshore wind energy generation to 5,600 MW by June 30, 2027; an additional 2,400 MW of offshore wind capacity remains to be procured in the future given the current PPAs under contract with the MA EDCs. The next RFP for offshore wind was filed with the MDPU for approval in May 2023 for at least 400 MW and up to 3,600 MW of additional offshore wind capacity.

Section 82 of the Acts of 2022 authorizes DOER to coordinate with other New England states to consider projects for long-term clean energy generation, transmission or capacity for the benefit of residents of the Commonwealth and the region. If DOER, in consultation with the Attorney General, determines that a project would satisfy all of the benefits listed in Section 82, then pursuant to Section 82 the EDCs shall enter into cost-effective long-term contracts with a maximum term of twenty years upon such a finding. On October 26, 2022, the Maine PUC announced its selection of a Transmission Project and a Generation Project to promote renewable energy development in northern Maine. On December 30, 2022, the DOER made a positive determination that the selected projects would have benefits to Massachusetts and the region and Massachusetts would procure up to 40% of the projects. Fitchburg is in the process of evaluating potential contractual commitments under Section 82. Negotiations for Section 82 have not yet begun.

FERC Transmission Formula Rate Proceedings - Pursuant to Section 206 of the Federal Power Act, there are several pending proceedings before the FERC concerning the justness and reasonableness of the Return on Equity (ROE) component of the ISO-New England, Inc. Participating Transmission Owners’ (PTOs) Regional Network Service and Local Network Service formula rates. In August 2013, FERC had found that the Transmission Owners existing ROE was unlawful, and set a new ROE. On April 14, 2017, the U.S. Court of Appeals for the D.C. Circuit (the Court) issued an opinion vacating and remanding FERC’s decision, finding that FERC had failed to articulate a satisfactory explanation for its orders. At this time, the ROE set in the vacated order will remain in place until further FERC action is taken. On November 21, 2019 the FERC issued an order in EL14-12, Midcontinent Independent System Operator ROE, in which FERC outlined a new methodology for calculating the ROE. The New England Transmission Owners (NETOs) thereafter filed a motion to reopen the record in their pending ROE dockets, which has been granted. This matter remains pending. The Company does not believe these proceedings will have a material adverse effect on its financial condition or results of operations.

On December 13, 2022, RENEW Northeast, Inc., a non-profit entity that advocates for the business interests of renewable power generators in New England filed a complaint with FERC against ISO-NE and the PTOs requesting a determination that certain open-access transmission tariff schedules are unjust and unreasonable to the extent they permit PTOs to directly assign to interconnection customers O&M costs associated with network upgrades. Fitchburg and Unitil Energy are PTOs, although Unitil Energy does not own transmission plant. The PTOs answered the complaint on January 23, 2023. This matter remains pending.

Legal Proceedings

The Company is involved in legal and administrative proceedings and claims of various types, including those which arise in the ordinary course of business. The Company believes, based upon information furnished by counsel and others, that the ultimate resolution of these claims will not have a material effect on its financial position, operating results or cash flows.

Debt and Financing Arrangements - Additional Information (Detail) - USD ($) shares in Millions, $ in Millions				3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 06, 2023	Sep. 29, 2022	Sep. 22, 2022	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022	Mar. 31, 2023
Line of Credit Facility [Line Items]
Weighted average interest rate on short term borrowings				6.30%	2.10%	6.10%	1.70%	3.30%
Capital lease obligation, current				$ 0.1	$ 0.1	$ 0.1	$ 0.1	$ 0.1	$ 0.1
Capital lease obligation, noncurrent				0.3	0.1	0.3	0.1	0.1	0.3
Accounts Payable				36.7	34.3	36.7	34.3	68.6
Total rental expense under operating leases				0.5	0.5	1.0	0.9
Net Utility Plant				1,357.8	1,279.1	1,357.8	1,279.1	1,331.7
Operating lease obligations						1.0	0.9
Other current operating lease obligation				1.7	1.5	1.7	1.5	1.5	1.7
Other noncurrent operating lease obligation				$ 3.5	$ 2.9	$ 3.5	$ 2.9	2.8	$ 3.5
Operating lease, weighted average remaining lease term				3 years 8 months 12 days	3 years 3 months 18 days	3 years 8 months 12 days	3 years 3 months 18 days
Operating lease, weighted average discount rate percentage				4.50%	3.60%	4.50%	3.60%
Assets under Capital Leases [Member]
Line of Credit Facility [Line Items]
Net Utility Plant				$ 0.8	$ 0.7	$ 0.8	$ 0.7	0.6
Net Utility Plant, accumulated amortization				0.4	0.4	$ 0.4	0.4	0.4
Northern Utilities Inc
Line of Credit Facility [Line Items]
Total funded indebtedness as percentage of capitalization						65.00%
Revolving Credit Facility
Line of Credit Facility [Line Items]
Revolving credit facility				200.0	$ 120.0	$ 200.0	$ 120.0	$ 200.0
Proceeds from lines of credit						193.6
Repayments of lines of credit						177.9
Accounts Payable				0.1		0.1
Credit Facility
Line of Credit Facility [Line Items]
Revolving credit facility				75.0		75.0
Credit Facility \| Third Amendment Credit Facility
Line of Credit Facility [Line Items]
Sublimit for the issuance of standby letters of credit		$ 25.0
Revolving credit facility		$ 200.0
Credit Facility \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Natural gas storage inventory				$ 8.7		8.7
Notes due date	Jul. 06, 2053
Cost of issue						$ 0.2
Issued note	13
Note issue percentage	5.96%
Debt Instrument, Covenant Description						The affirmative and negative covenants under the Credit Facility shall apply to Unitil until the Credit Facility terminates and all amounts borrowed under Credit Facility are paid in full (or, with respect to letters of credit, they are cash-collateralized). The only financial covenant in the Credit Facility provides that Unitil’s Funded Debt to Capitalization (as each term is defined in the Credit Facility) cannot exceed 65% tested on a quarterly basis
Credit Facility \| Revolving Credit Facility \| Fitchburg [Member]
Line of Credit Facility [Line Items]
Notes due date	Jul. 06, 2033
Note issue percentage	5.70%
Note issued	12
Credit Facility \| Revolving Credit Facility \| Third Amendment Credit Facility
Line of Credit Facility [Line Items]
Line of credit facility expiration date		Sep. 29, 2027
Credit Facility \| Revolving Credit Facility \| Third Amendment Credit Facility \| Secured Overnight Financing Rate [Member]
Line of Credit Facility [Line Items]
Credit facility, daily fluctuating rate of interest			0.10%
Credit Facility \| Revolving Credit Facility \| Third Amendment Credit Facility \| Secured Overnight Financing Rate [Member] \| Maximum [Member]
Line of Credit Facility [Line Items]
Debt instrument variable interest rate additional spread			1.375%
Credit Facility \| Revolving Credit Facility \| Third Amendment Credit Facility \| Secured Overnight Financing Rate [Member] \| Minimum [Member]
Line of Credit Facility [Line Items]
Debt instrument variable interest rate additional spread			1.125%

Regulatory Liabilities (Detail) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Regulatory Liabilities [Line Items]
Regulatory Liabilities	$ 53.9	$ 51.9	$ 64.8
Less: Current Portion of Regulatory Liabilities	18.4	15.0	25.9
Regulatory Liabilities – noncurrent	35.5	36.9	38.9
Income Taxes
Regulatory Liabilities [Line Items]
Regulatory Liabilities	39.6	41.0	42.6
Rate Adjustment Mechanisms
Regulatory Liabilities [Line Items]
Regulatory Liabilities	$ 14.3	$ 10.9	$ 22.2

Insider Trading Arrangements	6 Months Ended
Insider Trading Arrangements	Jun. 30, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Dividends Declared Per Share (Tables)

6 Months Ended

Jun. 30, 2023

DIVIDENDS DECLARED PER SHARE [Abstract]

Schedule of Dividends Declared


Declaration Date	Date Paid (Payable)	Shareholder of Record Date	Dividend Amount
07/26/23	08/28/23	08/14/23	$	0.405
04/26/23	05/30/23	05/15/23	$	0.405
01/25/23	02/28/23	02/14/23	$	0.405
10/26/22	11/28/22	11/14/22	$	0.390
07/27/22	08/26/22	08/12/22	$	0.390
04/27/22	05/27/22	05/13/22	$	0.390
01/26/22	02/25/22	02/11/22	$	0.390

Regulatory Assets (Detail) - USD ($)
$ in Millions

Jun. 30, 2023

Dec. 31, 2022

Jun. 30, 2022

Regulatory Assets [Line Items]

Regulatory Assets

$ 108.3

$ 114.3

$ 148.0

Less: Current Portion of Regulatory Assets

^[1]

56.8

66.5

41.4

Regulatory Assets – noncurrent

51.5

47.8

106.6

Environmental Matters

Regulatory Assets [Line Items]

Regulatory Assets

6.1

5.9

4.5

Other Deferred Charges

Regulatory Assets [Line Items]

Regulatory Assets

11.0

11.1

13.3

Retirement Benefits

Regulatory Assets [Line Items]

Regulatory Assets

27.2

29.1

86.9

Deferred Storm Charges

Regulatory Assets [Line Items]

Regulatory Assets

8.5

3.4

2.9

Income Taxes

Regulatory Assets [Line Items]

Regulatory Assets

1.5

1.8

2.2

Energy Supply and Other Rate Adjustment Mechanisms

Regulatory Assets [Line Items]

Regulatory Assets

$ 54.0

$ 63.0

$ 38.2

[1]	Reflects amounts included in the Accrued Revenue on the Company’s Consolidated Balance Sheets.

Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2023

Accounting Policies [Abstract]

Nature of Operations

The Company’s earnings historically have been seasonal and typically higher in the first and fourth quarters when customers use gas for heating purposes.

Basis of Presentation

Utility Revenue Recognition

In the following tables, revenue is classified by the types of goods/services rendered and market/customer type.


	Three Months Ended June 30, 2023
Electric and Gas Operating Revenues (millions):	Electric			Gas			Total
Billed and Unbilled Revenue:
Residential	$	39.8		$	17.9		$	57.7
Commercial and Industrial		28.1			26.4			54.5
Other		1.9			1.0			2.9
Total Billed and Unbilled Revenue		69.8			45.3			115.1
Rate Adjustment Mechanism Revenue		(5.3	)		(6.4	)		(11.7	)
Total Electric and Gas Operating Revenues	$	64.5		$	38.9		$	103.4


	Three Months Ended June 30, 2022
Electric and Gas Operating Revenues (millions):	Electric			Gas			Total
Billed and Unbilled Revenue:
Residential	$	33.8		$	18.1		$	51.9
Commercial and Industrial		25.7			28.0			53.7
Other		4.6			3.5			8.1
Total Billed and Unbilled Revenue		64.1			49.6			113.7
Rate Adjustment Mechanism Revenue		(9.8	)		(5.0	)		(14.8	)
Total Electric and Gas Operating Revenues	$	54.3		$	44.6		$	98.9


	Six Months Ended June 30, 2023
Electric and Gas Operating Revenues (millions):	Electric		Gas			Total
Billed and Unbilled Revenue:
Residential	$	99.9	$	67.0		$	166.9
Commercial and Industrial		62.9		95.6			158.5
Other		4.6		4.6			9.2
Total Billed and Unbilled Revenue		167.4		167.2			334.6
Rate Adjustment Mechanism Revenue		5.3		(16.3	)		(11.0	)
Total Electric and Gas Operating Revenues	$	172.7	$	150.9		$	323.6


	Six Months Ended June 30, 2022
Electric and Gas Operating Revenues (millions):	Electric			Gas			Total
Billed and Unbilled Revenue:
Residential	$	83.0		$	63.6		$	146.6
Commercial and Industrial		56.7			92.7			149.4
Other		9.1			7.0			16.1
Total Billed and Unbilled Revenue		148.8			163.3			312.1
Rate Adjustment Mechanism Revenue		(5.3	)		(15.3	)		(20.6	)
Total Electric and Gas Operating Revenues	$	143.5		$	148.0		$	291.5


Revenue Decoupling
Estimated Percentage of Decoupled Sales
For Periods Presented
Electric
Before June 1, 2022	27%
After June 1, 2022	Substantially All
Gas
Before August 1, 2022	11%
After August 1, 2022	43%

Income Taxes

Cash and Cash Equivalents

30, 2023, June 30, 2022 and December 31, 2022, the Unitil subsidiaries had deposited $3.3 million, $1.7 million and $6.0 million, respectively to satisfy their ISO-NE obligations

Allowance for Doubtful Accounts

The Allowance for Doubtful Accounts as of June 30, 2023, June 30, 2022 and December 31, 2022, was as follows:


	June 30,				December 31,
(millions)	2023		2022		2022
Allowance for Doubtful Accounts	$	2.2	$	2.7	$	2.6

Accrued Revenue


	June 30,				December 31,
Accrued Revenue (millions)	2023		2022		2022
Regulatory Assets – Current	$	56.8	$	41.4	$	66.5
Unbilled Revenues, net		3.6		4.2		6.3
Total Accrued Revenue	$	60.4	$	45.6	$	72.8

Exchange Gas Receivable


	June 30,				December 31,
Exchange Gas Receivable (millions)	2023		2022		2022
Northern Utilities	$	8.7	$	12.5	$	16.3
Fitchburg		0.7		0.9		1.7
Total Exchange Gas Receivable	$	9.4	$	13.4	$	18.0

Gas Inventory


	June 30,				December 31,
Gas Inventory (millions)	2023		2022		2022
Natural Gas	$	0.6	$	0.5	$	1.0
Propane		0.3		0.4		0.4
Liquefied Natural Gas & Other		0.1		0.1		0.4
Total Gas Inventory	$	1.0	$	1.0	$	1.8

Utility Plant

Leases

Regulatory Accounting


	June 30,				December 31,
Regulatory Assets consist of the following (millions)	2023		2022		2022
Retirement Benefits	$	27.2	$	86.9	$	29.1
Energy Supply and Other Rate Adjustment Mechanisms		54.0		38.2		63.0
Deferred Storm Charges		8.5		2.9		3.4
Environmental		6.1		4.5		5.9
Income Taxes		1.5		2.2		1.8
Other Deferred Charges		11.0		13.3		11.1
Total Regulatory Assets		108.3		148.0		114.3
Less: Current Portion of Regulatory Assets(1)		56.8		41.4		66.5
Regulatory Assets – noncurrent	$	51.5	$	106.6	$	47.8

(1)

Reflects amounts included in the Accrued Revenue on the Company’s Consolidated Balance Sheets.


	June 30,				December 31,
Regulatory Liabilities consist of the following (millions)	2023		2022		2022
Income Taxes (Note 8)	$	39.6	$	42.6	$	41.0
Rate Adjustment Mechanisms		14.3		22.2		10.9
Total Regulatory Liabilities		53.9		64.8		51.9
Less: Current Portion of Regulatory Liabilities		18.4		25.9		15.0
Regulatory Liabilities – noncurrent	$	35.5	$	38.9	$	36.9

Derivatives

Investments in Marketable Securities


	June 30,				December 31,
Fair Value of Marketable Securities (millions)	2023		2022		2022
Money Market Funds	$	5.8	$	5.4	$	5.8
Total Marketable Securities	$	5.8	$	5.4	$	5.8


	June 30,				December 31,
Fair Value of Marketable Securities (millions)	2023		2022		2022
Equity Funds	$	1.0	$	0.4	$	0.5
Money Market Funds		0.1		0.4		0.1
Total Marketable Securities	$	1.1	$	0.8	$	0.6

Energy Supply Obligations


	June 30,				December 31,
Energy Supply Obligations (millions)	2023		2022		2022
Current:
Exchange Gas Obligation	$	8.7	$	12.5	$	16.3
Renewable Energy Portfolio Standards		5.2		4.1		7.8
Total Energy Supply Obligations	$	13.9	$	16.6	$	24.1

Subsequent Events

Income Taxes (Tables)

6 Months Ended

Jun. 30, 2023

Income Tax Disclosure [Abstract]

Differences Between Provisions for Income Taxes and Provisions Calculated at Statutory Federal Tax Rate

The differences between the Company’s provisions for Income Taxes and the provisions calculated at the statutory federal tax rate, expressed in percentages, are shown in the following table:


	For the Six Months Ended June 30,
	2023			2022
Statutory Federal Income Tax Rate		21	%		21	%
Income Tax Effects of:
State Income Taxes, net		6			6
Utility Plant Differences		(3	)		(5	)
Effective Income Tax Rate		24	%		22	%

Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Operating Activities:
Net Income	$ 28.3	$ 26.4
Adjustments to Reconcile Net Income to Cash Provided by Operating Activities:
Depreciation and Amortization	33.3	30.3
Deferred Tax Provision	8.8	7.2
Changes in Working Capital Items:
Accounts Receivable	14.3	12.6
Accrued Revenue	12.4	15.6
Exchange Gas Receivable	8.6	(6.0)
Regulatory Liabilities	3.4	16.4
Accounts Payable	(31.9)	(18.1)
Other Changes in Working Capital Items	(6.1)	(7.6)
Deferred Regulatory and Other Charges	(13.6)	(10.2)
Other, net	4.9	4.4
Cash Provided by Operating Activities	62.4	71.0
Investing Activities:
Property, Plant and Equipment Additions	(57.6)	(45.3)
Cash (Used in) Investing Activities	(57.6)	(45.3)
Financing Activities:
Proceeds from (Repayment of) Short-Term Debt, net	15.7	(17.9)
Repayment of Long-Term Debt	(2.8)	(2.8)
Net (Decrease) Increase in Exchange Gas Financing	(7.6)	5.8
Increase (Decrease) in Capital Lease Obligations	0.2	(0.1)
Dividends Paid	(13.1)	(12.6)
Proceeds from Issuance of Common Stock	0.6	0.5
Cash (Used in) Financing Activities	(7.0)	(27.1)
Net (Decrease) in Cash and Cash Equivalents	(2.2)	(1.4)
Cash and Cash Equivalents at Beginning of Period	9.0	6.5
Cash and Cash Equivalents at End of Period	6.8	5.1
Supplemental Cash Flow Information:
Interest Paid	15.5	12.8
Income Taxes Paid	0.0	1.1
Payments on Capital Leases	0.1	0.1
Non-cash Investing Activity:
Capital Expenditures Included in Accounts Payable	5.3	3.9
Right-of-Use Assets Obtained in Exchange for Lease Obligations	$ 1.8	$ 0.5

Environmental Matters (Tables)

6 Months Ended

Jun. 30, 2023

Text Block [Abstract]

Environmental Obligations Recognized by Company

The following table sets forth a summary of changes in the Company’s liability for Environmental Obligations for the six months ended June 30, 2023 and 2022.


Environmental Obligations (millions)
	June 30,
	2023		2022
Total Balance at Beginning of Period	$	4.4	$	2.7
Additions		0.5		0.3
Less: Payments / Reductions		0.2		0.2
Total Balance at End of Period		4.7		2.8
Less: Current Portion		0.6		0.6
Noncurrent Balance at End of Period	$	4.1	$	2.2

Cover Page - shares	6 Months Ended
Cover Page - shares	Jun. 30, 2023	Jul. 28, 2023
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Amendment Flag	false
Document Period End Date	Jun. 30, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Entity Registrant Name	UNITIL CORPORATION
Entity Central Index Key	0000755001
Entity File Number	1-8858
Entity Tax Identification Number	02-0381573
Entity Incorporation, State or Country Code	NH
Entity Shell Company	false
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Emerging Growth Company	false
Entity Address, Address Line One	6 Liberty Lane West
Entity Address, City or Town	Hampton
Entity Address, State or Province	NH
Entity Address, Postal Zip Code	03842-1720
City Area Code	603
Local Phone Number	772-0775
Title of 12(b) Security	Common Stock
Trading Symbol	UTL
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding		16,092,469

Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Current Assets:
Cash and Cash Equivalents	$ 6.8	$ 9.0	$ 5.1
Accounts Receivable, Net	59.5	73.8	54.3
Accrued Revenue	60.4	72.8	45.6
Exchange Gas Receivable	9.4	18.0	13.4
Gas Inventory	1.0	1.8	1.0
Materials and Supplies	12.9	11.4	9.7
Prepayments and Other	11.3	8.0	10.0
Total Current Assets	161.3	194.8	139.1
Utility Plant:
Electric	638.4	627.5	610.1
Gas	1,060.9	1,043.6	988.9
Common	68.9	67.6	66.7
Construction Work in Progress	64.2	52.6	56.2
Total Utility Plant	1,832.4	1,791.3	1,721.9
Less: Accumulated Depreciation	474.6	459.6	442.8
Net Utility Plant	1,357.8	1,331.7	1,279.1
Other Noncurrent Assets:
Regulatory Assets	51.5	47.8	106.6
Operating Lease Right of Use Assets	5.2	4.3	4.4
Other Assets	19.5	11.8	17.9
Total Other Noncurrent Assets	76.2	63.9	128.9
TOTAL ASSETS	1,595.3	1,590.4	1,547.1
Current Liabilities:
Accounts Payable	36.7	68.6	34.3
Short-Term Debt	131.7	116.0	46.2
Long-Term Debt, Current Portion	6.9	6.7	8.2
Regulatory Liabilities	18.4	15.0	25.9
Energy Supply Obligations	13.9	24.1	16.6
Interest Payable	5.2	5.0	4.8
Environmental Obligations	0.6	0.6	0.6
Taxes Payable	2.3	0.4	0.1
Other Current Liabilities	22.3	23.7	18.3
Total Current Liabilities	238.0	260.1	155.0
Noncurrent Liabilities:
Retirement Benefit Obligations	44.3	46.8	135.9
Deferred Income Taxes, Net	171.3	163.4	136.4
Cost of Removal Obligations	123.2	116.1	112.4
Regulatory Liabilities	35.5	36.9	38.9
Environmental Obligations	4.1	3.8	2.2
Other Noncurrent Liabilities	8.3	6.6	6.9
Total Noncurrent Liabilities	386.7	373.6	432.7
Capitalization:
Long-Term Debt, Less Current Portion	486.2	489.1	495.1
Stockholders' Equity:
Common Equity (Authorized: 25,000,000 and Outstanding:16,091,419, 16,034,635 and 16,043,355 Shares)	336.5	334.9	334.1
Retained Earnings	147.7	132.5	130.0
Total Common Stock Equity	484.2	467.4	464.1
Preferred Stock	0.2	0.2	0.2
Total Stockholders' Equity	484.4	467.6	464.3
Total Capitalization	970.6	956.7	959.4
Commitments and Contingencies (Notes 6 & 7)
TOTAL LIABILITIES AND CAPITALIZATION	$ 1,595.3	$ 1,590.4	$ 1,547.1

Components of Exchange Gas Receivable (Detail) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Receivables [Line Items]
Total Exchange Gas Receivable	$ 9.4	$ 18.0	$ 13.4
Northern Utilities Inc
Receivables [Line Items]
Total Exchange Gas Receivable	8.7	16.3	12.5
Fitchburg
Receivables [Line Items]
Total Exchange Gas Receivable	$ 0.7	$ 1.7	$ 0.9

Common Stock And Preferred Stock - Additional Information (Detail) - USD ($)		3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 24, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Class of Stock [Line Items]
Common stock, shares outstanding		16,091,419	16,034,635	16,091,419	16,034,635	16,043,355
Common stock, shares issued		5,189	4,352	10,524	9,863
Proceeds from Issuance of Common Stock				$ 600,000	$ 500,000
Restricted Stock Units Granted				$ 48.02	$ 47.44
Share based compensation expense				$ 1,300,000	$ 1,800,000
Percentage of fully-vested restricted stock units that directors will receive in common shares when settled				70.00%
Percentage of fully-vested restricted stock units that directors will receive in cash when settled				30.00%
Preferred Stock		$ 200,000	$ 200,000	$ 200,000	200,000	$ 200,000
Maximum
Class of Stock [Line Items]
Dividend declared				$ 100,000	$ 100,000
Restricted Stock
Class of Stock [Line Items]
Restricted stock vesting period				4 years
Restricted stock non-vested		64,243	73,178	64,243	73,178
Fair value of liabilities associated with fully vested RSUs that will be settled in cash		$ 1,000,000	$ 1,000,000	$ 1,000,000	$ 1,000,000	$ 1,000,000
Unrecognized share based compensation		$ 900,000		$ 900,000
Share compensation recognition period				2 years 7 months 6 days
Restricted Stock Units Granted	18,770
Aggregate Market Value	$ 1,000,000
Forfeitures under the stock plan				0
Cancellations under the stock plan				0
Restricted Stock \| Maximum
Class of Stock [Line Items]
Restricted stock available for awards		677,500		677,500
Restricted stock that may be awarded in any one calendar year to any one participant		20,000		20,000
Restricted Stock \| Vesting Annually
Class of Stock [Line Items]
Restricted stock vesting percentage annually				25.00%
Restricted Stock Units (RSUs)
Class of Stock [Line Items]
Restricted Stock Units Granted				0
Restricted stock units outstanding			39,595		39,595
Weighted-Average Stock Price			$ 39.37		$ 39.37
Performance Shares [Member]
Class of Stock [Line Items]
Restricted stock non-vested		18,770		18,770
Restricted Stock Units Granted				$ 51.83
Share based compensation expense				$ 200,000
Unrecognized share based compensation		$ 1,000,000		$ 1,000,000
Share compensation recognition period				2 years 6 months
Restricted Stock Units Granted	18,770
Aggregate Market Value	$ 1,000,000
Forfeitures under the stock plan				0
Cancellations under the stock plan				0
Series 6 \| Unitil Energy Systems Inc
Class of Stock [Line Items]
Preferred stock, outstanding		1,727	1,861	1,727	1,861	1,861
Preferred Stock		$ 200,000	$ 200,000	$ 200,000	$ 200,000	$ 200,000
Dividend rate				6.00%	6.00%	6.00%
Dividend and Distribution Reinvestment and Share Purchase Plan
Class of Stock [Line Items]
Proceeds from Issuance of Common Stock				$ 574,700
Dividend and Distribution Reinvestment and Share Purchase Plan \| Average
Class of Stock [Line Items]
Common stock price per share		$ 54.61		$ 54.61
Dividend and Distribution Reinvestment and Share Purchase Plan \| Common Stock
Class of Stock [Line Items]
Common stock, shares issued				10,524

Differences Between Provisions for Income Taxes and Provisions Calculated at Statutory Federal Tax Rate (Detail)	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Income Tax Examination [Line Items]
Statutory Federal Income Tax Rate	21.00%	21.00%
State Income Taxes, net	6.00%	6.00%
Utility Plant Differences	(3.00%)	(5.00%)
Effective Income Tax Rate	24.00%	22.00%

Income Taxes

6 Months Ended

Jun. 30, 2023

Income Tax Disclosure [Abstract]

Income Taxes

Note 8: INCOME TAXES

The differences between the Company’s provisions for Income Taxes and the provisions calculated at the statutory federal tax rate, expressed in percentages, are shown in the following table:


	For the Six Months Ended June 30,
	2023			2022
Statutory Federal Income Tax Rate		21	%		21	%
Income Tax Effects of:
State Income Taxes, net		6			6
Utility Plant Differences		(3	)		(5	)
Effective Income Tax Rate		24	%		22	%

Under the Company’s Tax Sharing Agreement (the Agreement) which was approved upon the formation of Unitil as a public utility holding company, the Company files consolidated Federal and State tax returns and Unitil Corporation and each of its utility operating subsidiaries recognize the results of their operations in its tax returns as if it were a stand-alone taxpayer. The Agreement provides that the Company will account for income taxes in compliance with U.S. GAAP and regulatory accounting principles. The Company has evaluated its tax positions at June 30, 2023 in accordance with the FASB Codification, and has concluded that no adjustment for recognition, de-recognition, settlement or foreseeable future events to any tax liabilities or assets as defined by the FASB Codification is required. The Company remains subject to examination by the Internal Revenue Service (IRS), and Maine, Massachusetts, and New Hampshire tax authorities for the tax periods ended December 31, 2021; December 31, 2020; and December 31, 2019.

Income tax filings for the year ended December 31, 2021 have been filed with the IRS, Massachusetts Department of Revenue, the Maine Revenue Service, and the New Hampshire Department of Revenue Administration. In the Company’s federal tax returns for the year ended December 31, 2021, which were filed with the IRS in October 2022, the Company utilized federal Net Operating Loss Carryforward (NOLC) assets of $2.4 million. The Company had approximately $5.3 million of NOLC assets available to offset current taxes payable as of December 31, 2021. In fiscal year 2022, the Company recognized the utilization of approximately $2.8 million of the NOLC asset. In addition, at December 31, 2022, the Company had $1.0 million of cumulative state tax credit carryforwards to offset future income taxes payable. If unused, the Company’s state tax credit carryforwards will begin to expire in 2027.

In March 2020, the Coronavirus Aid, Relief and Economic Security (CARES) Act was signed into law. The CARES Act included several tax changes as part of its economic package. These changes principally related to expanded Net Operating Loss carryback periods, increases to interest deductibility limitations, and accelerated Alternative Minimum Tax refunds. Additionally, the CARES Act enacted the Employee Retention Credit (ERC) to incentivize companies to retain employees. The ERC is a 50% credit on employee wages for employees that are retained and cannot perform their job duties at 100% capacity as a result of coronavirus pandemic restrictions.

In December 2020, the Consolidated Appropriations Act, 2021 (CAA) was signed into law. The CAA included additional funding through tax credits as part of its economic package for 2021. These changes include the temporary removal of deduction limitations on business meals through December 2022 and additional funding for the ERC with expanded benefits extended through June 30, 2021. The expanded ERC is a 70% credit on employee wages for employees that are retained and cannot perform their job duties at 100% capacity as a result of coronavirus pandemic restrictions.

In March 2021, the American Rescue Plan Act of 2021 (ARPA) was signed into law. The ARPA included certain provisions that provide economic relief for the ongoing COVID-19 pandemic, such as extending the ERC through December 31, 2021, and other future governmental revenue producing provisions, such as expanding the scope for deduction limitations on executive compensation in future years.

In August 2022, the Inflation Reduction Act of 2022 (IRA) was signed into law. The IRA included new taxes on corporations, including the Corporate Alternative Minimum Tax (AMT) and the Excise Tax on Repurchase of Corporate Stock. The AMT is equal to 15% of a corporation’s adjusted financial statement income (AFSI). The AMT applies to companies that have a 3 year average AFSI of greater than $1 billion. The IRA also extended and modified certain renewable energy related credits.

The Company has evaluated each of the CARES, CAA ARPA, and IRA provisions and determined that they do not have a material effect on the Company’s financial statements as of June 30, 2023.

In December 2017, the Tax Cuts and Jobs Act (TCJA), which included a reduction to the corporate federal income tax rate to 21% effective January 1, 2018, was signed into law. In accordance with FASB Codification Topic 740, the Company revalued its Accumulated Deferred Income Taxes (ADIT) at the new 21% tax rate at which the ADIT will be reversed in future periods. Based on communications received by the Company from its state regulators in rate cases and other regulatory proceedings in the first quarter of 2018 and as prescribed in the TCJA, FERC guidance and IRS normalization rules, the benefit of protected excess ADIT amounts will be subject to flow back to customers in future utility rates according to the Average Rate Assumption Method (ARAM). ARAM reconciles excess ADIT at the reversal rate of the underlying book/tax temporary timing differences. The Company estimates the ARAM flow back period for protected and unprotected excess ADIT to be between fifteen and twenty years over the remaining life of the related utility plant. Subject to regulatory approval, the Company expects to flow back to customers a net $47.1 million of protected excess ADIT created as a result of the lowering of the statutory tax rate by the TCJA over periods estimated to be fifteen to twenty years. As of June 30, 2023, the Company flowed back $7.8 million to customers in its Massachusetts, Maine, New Hampshire, and federal jurisdictions.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-14

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 270
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 17
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details