Debt and Financing Arrangements (Tables)

12 Months Ended

Dec. 31, 2023

Details on Long Term Debt

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

	December 31,
Long-Term Debt (millions)	2023		2022
Unitil Corporation:
3.70% Senior Notes, Due August 1, 2026	$	30.0	$	30.0
3.43% Senior Notes, Due December 18, 2029		30.0		30.0
Unitil Energy First Mortgage Bonds:
6.96% Senior Secured Notes, Due September 1, 2028		10.0		12.0
8.00% Senior Secured Notes, Due May 1, 2031		12.0		13.5
6.32% Senior Secured Notes, Due September 15, 2036		15.0		15.0
3.58% Senior Secured Notes, Due September 15, 2040		27.5		27.5
4.18% Senior Secured Notes, Due November 30, 2048		30.0		30.0
Fitchburg:
6.79% Senior Notes, Due October 15, 2025		—		2.0
3.52% Senior Notes, Due November 1, 2027		10.0		10.0
7.37% Senior Notes, Due January 15, 2029		7.2		8.4
5.90% Senior Notes, Due December 15, 2030		15.0		15.0
7.98% Senior Notes, Due June 1, 2031		14.0		14.0
5.70% Senior Notes, Due July 2, 2033		12.0		—
3.78% Senior Notes, Due September 15, 2040		27.5		27.5
4.32% Senior Notes, Due November 1, 2047		15.0		15.0
5.96% Senior Notes, Due July 2, 2053		13.0		—
Northern Utilities:
3.52% Senior Notes, Due November 1, 2027		20.0		20.0
7.72% Senior Notes, Due December 3, 2038		50.0		50.0
3.78% Senior Notes, Due September 15, 2040		40.0		40.0
4.42% Senior Notes, Due October 15, 2044		50.0		50.0
4.32% Senior Notes, Due November 1, 2047		30.0		30.0
4.04% Senior Notes, Due September 12, 2049		40.0		40.0
Granite State:
3.72% Senior Notes, Due November 1, 2027		15.0		15.0
Unitil Realty Corp.:
2.64% Senior Secured Notes, Due December 18, 2030		4.0		4.2
Total Long-Term Debt		517.2		499.1
Less: Unamortized Debt Issuance Costs		3.2		3.3
Total Long-Term Debt, net of Unamortized Debt Issuance Costs		514.0		495.8
Less: Current Portion(1)		4.9		6.7
Total Long-Term Debt, Less Current Portion	$	509.1	$	489.1

The Current Portion of Long-Term Debt includes sinking fund payments.

Fair Value of Long Term Debt

	December 31,
Estimated Fair Value of Long-Term Debt (millions)	2023		2022
Estimated Fair Value of Long-Term Debt	$	470.5	$	455.3

Summary of Interest Expense and Interest Income

A summary of interest expense and interest income is provided in the following table:

Interest Expense, Net (millions)	2023			2022			2021
Interest Expense
Long-Term Debt	$	24.7		$	24.7		$	26.0
Short-Term Debt		9.2			3.0			0.8
Regulatory Liabilities & Other		1.0			0.6			0.4
Subtotal Interest Expense		34.9			28.3			27.2
Interest Income
Regulatory Assets		(3.3	)		(1.0	)		(0.5	)
AFUDC(1) and Other		(2.9	)		(1.8	)		(1.1	)
Subtotal Interest Income		(6.2	)		(2.8	)		(1.6	)
Total Interest Expense, Net	$	28.7		$	25.5		$	25.6

(1)AFUDC—Allowance for Funds Used During Construction

Borrowing Limits Amounts Outstanding and Amounts Available under Credit Facility

The following table details the borrowing limits, amounts outstanding and amounts available under the revolving Credit Facility as of December 31, 2023 and December 31, 2022:

	December 31,
Revolving Credit Facility (millions)	2023		2022
Limit	$	200.0	$	200.0
Short-Term Borrowings Outstanding	$	162.0	$	116.0
Available	$	38.0	$	84.0

Summary of Company's Contractual Obligations for Log-term Debt

The following table lists the Company’s contractual obligations for long-term debt as of December 31, 2023.

			Payments Due by Period
Long-Term Debt Contractual Obligations (millions) as of December 31, 2022	Total		2024		2025		2026		2027		2028		2029 & Beyond
Long-Term Debt	$	517.2	$	4.9	$	4.9	$	37.9	$	55.7	$	10.7	$	403.1
Interest on Long-Term Debt		342.1		24.7		24.4		24.0		22.3		19.9		226.8
Total	$	859.3	$	29.6	$	29.3	$	61.9	$	78.0	$	30.6	$	629.9

Classification of the Company Lease Obligations

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

	December 31,
Lease Obligations (millions)	2023		2022
Operating Lease Obligations:
Operating Lease Obligations (current portion)	$	1.9	$	1.5
Operating Lease Obligations (long-term portion)		3.7		2.8
Total Operating Lease Obligations		5.6		4.3
Capital Lease Obligations:
Other Current Liabilities (current portion)		0.1		0.1
Other Noncurrent Liabilities (long-term portion)		0.4		0.1
Total Capital Lease Obligations		0.5		0.2
Total Lease Obligations	$	6.1	$	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 December 31, 2023. The payments for operating leases consist of $1.9 million of current operating lease obligations and $3.7 million of noncurrent operating lease obligations on the Company’s Consolidated Balance Sheets as of December 31, 2023. The payments for capital leases consist of $0.1 million of current Capital Lease Obligations, which are included in Other Current Liabilities, and $0.4 million of noncurrent Capital Lease Obligations, which are included in Other Noncurrent Liabilities, on the Company’s Consolidated Balance Sheets as of December 31, 2023.

Lease Payments ($000’s) Year Ending December 31,	Operating Leases		Capital Leases
2024	$	2,063	$	152
2025		1,502		120
2026		1,171		107
2027		898		104
2028		336		19
2029-2033		84		—
Total Payments		6,054		502
Less: Interest		493		26
Amount of Lease Obligations Recorded on Consolidated Balance Sheets	$	5,561	$	476