Regulatory assets and liabilities (Tables)

6 Months Ended

Jun. 30, 2025

Regulatory Assets and Liabilities Disclosure [Abstract]

The following table summarizes the individual components of unamortized regulatory assets and liabilities:


	Estimated Recovery or Refund Period as of June 30, 2025	*	June 30, 2025		June 30, 2024		December 31, 2024
			(In thousands)
Regulatory assets:
Current:
Environmental compliance programs	Up to 1 year		$	63,245	$	84,486	$	76,964
Natural gas costs recoverable through rate adjustments	Up to 1 year		36,567		105,064		91,091
Conservation programs	Up to 1 year		21,541		15,713		19,123
Decoupling mechanisms	Up to 1 year		7,974		2,139		6,767
Cost recovery mechanisms	Up to 1 year		6,389		6,074		5,114
Electric fuel and purchased power deferral	Up to 1 year		2,050		3,024		9,662
Other	Up to 1 year		3,978		1,322		6,715
			141,744		217,822		215,436
Noncurrent:
Pension and postretirement benefits	**		142,064		142,511		142,064
Cost recovery mechanisms	Up to 24 years		70,533		82,984		76,542
Plant costs/asset retirement obligations	Over plant lives		46,684		45,342		47,042
Manufactured gas plant site remediation	-		27,212		25,704		27,964
Taxes recoverable from customers	Over plant lives		12,220		12,311		12,221
Covid-19 deferred costs	Up to 3 years		3,886		3,245		4,167
Long-term debt refinancing costs	Up to 36 years		1,718		2,306		2,011
Natural gas costs recoverable through rate adjustments	-		—		15,870		—
Electric fuel and purchased power deferral	-		—		12,160		4,349
Environmental compliance programs	-		—		2,858		—
Other	Up to 14 years		4,985		6,043		5,990
			309,302		351,334		322,350
Total regulatory assets			$	451,046	$	569,156	$	537,786
Regulatory liabilities:
Current:
Environmental compliance programs	Up to 1 year		$	72,520	$	72,644	$	72,387
Natural gas costs refundable through rate adjustments	Up to 1 year		44,377		60,400		45,427
Provision for rate refund	Up to 1 year		4,254		7,767		3,677
Margin sharing	Up to 1 year		3,410		2,188		4,156
Taxes refundable to customers	Up to 1 year		2,197		2,074		2,163
Conservation programs	Up to 1 year		1,996		3,330		2,082
Cost recovery mechanisms	Up to 1 year		636		3,841		1,720
Other	Up to 1 year		4,864		6,291		5,555
			134,254		158,535		137,167
Noncurrent:
Plant removal and decommissioning costs	Over plant lives		225,142		222,668		217,603
Taxes refundable to customers	Over plant lives		180,212		187,827		185,402
Cost recovery mechanisms	Up to 17 years		35,794		26,286		30,354
Accumulated deferred investment tax credit	Over plant lives		19,814		16,518		18,788
Pension and postretirement benefits	**		4,862		6,043		4,862
Other	Up to 13 years		2,344		2,024		2,161
			468,168		461,366		459,170
Total regulatory liabilities			$	602,422	$	619,901	$	596,337
Net regulatory position			$	(151,376)	$	(50,745)	$	(58,551)

*Estimated recovery or refund period for amounts currently being recovered or refunded in rates to customers.

** Recovered as expense is incurred or cash contributions are made.

Schedule of Regulatory Liabilities

The following table summarizes the individual components of unamortized regulatory assets and liabilities:


	Estimated Recovery or Refund Period as of June 30, 2025	*	June 30, 2025		June 30, 2024		December 31, 2024
			(In thousands)
Regulatory assets:
Current:
Environmental compliance programs	Up to 1 year		$	63,245	$	84,486	$	76,964
Natural gas costs recoverable through rate adjustments	Up to 1 year		36,567		105,064		91,091
Conservation programs	Up to 1 year		21,541		15,713		19,123
Decoupling mechanisms	Up to 1 year		7,974		2,139		6,767
Cost recovery mechanisms	Up to 1 year		6,389		6,074		5,114
Electric fuel and purchased power deferral	Up to 1 year		2,050		3,024		9,662
Other	Up to 1 year		3,978		1,322		6,715
			141,744		217,822		215,436
Noncurrent:
Pension and postretirement benefits	**		142,064		142,511		142,064
Cost recovery mechanisms	Up to 24 years		70,533		82,984		76,542
Plant costs/asset retirement obligations	Over plant lives		46,684		45,342		47,042
Manufactured gas plant site remediation	-		27,212		25,704		27,964
Taxes recoverable from customers	Over plant lives		12,220		12,311		12,221
Covid-19 deferred costs	Up to 3 years		3,886		3,245		4,167
Long-term debt refinancing costs	Up to 36 years		1,718		2,306		2,011
Natural gas costs recoverable through rate adjustments	-		—		15,870		—
Electric fuel and purchased power deferral	-		—		12,160		4,349
Environmental compliance programs	-		—		2,858		—
Other	Up to 14 years		4,985		6,043		5,990
			309,302		351,334		322,350
Total regulatory assets			$	451,046	$	569,156	$	537,786
Regulatory liabilities:
Current:
Environmental compliance programs	Up to 1 year		$	72,520	$	72,644	$	72,387
Natural gas costs refundable through rate adjustments	Up to 1 year		44,377		60,400		45,427
Provision for rate refund	Up to 1 year		4,254		7,767		3,677
Margin sharing	Up to 1 year		3,410		2,188		4,156
Taxes refundable to customers	Up to 1 year		2,197		2,074		2,163
Conservation programs	Up to 1 year		1,996		3,330		2,082
Cost recovery mechanisms	Up to 1 year		636		3,841		1,720
Other	Up to 1 year		4,864		6,291		5,555
			134,254		158,535		137,167
Noncurrent:
Plant removal and decommissioning costs	Over plant lives		225,142		222,668		217,603
Taxes refundable to customers	Over plant lives		180,212		187,827		185,402
Cost recovery mechanisms	Up to 17 years		35,794		26,286		30,354
Accumulated deferred investment tax credit	Over plant lives		19,814		16,518		18,788
Pension and postretirement benefits	**		4,862		6,043		4,862
Other	Up to 13 years		2,344		2,024		2,161
			468,168		461,366		459,170
Total regulatory liabilities			$	602,422	$	619,901	$	596,337
Net regulatory position			$	(151,376)	$	(50,745)	$	(58,551)

*Estimated recovery or refund period for amounts currently being recovered or refunded in rates to customers.

** Recovered as expense is incurred or cash contributions are made.