Regulatory assets and liabilities (Tables)

3 Months Ended

Mar. 31, 2024

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 March 31, 2024	*	March 31, 2024		March 31, 2023		December 31, 2023
			(In thousands)
Regulatory assets:
Current:
Natural gas costs recoverable through rate adjustments	Up to 1 year		$	110,481	$	198,166	$	98,844
Electric fuel and purchased power deferral	Up to 1 year		17,061		3,279		33,918
Conservation programs	Up to 1 year		13,735		8,599		14,425
Environmental compliance programs	Up to 1 year		7,443		1,191		5,525
Cost recovery mechanisms	Up to 1 year		6,454		3,954		9,153
Other	Up to 1 year		3,440		1,129		10,627
			158,614		216,318		172,492
Noncurrent:
Pension and postretirement benefits	**		142,511		143,349		142,511
Cost recovery mechanisms	Up to 25 years		84,546		65,732		85,944
Environmental compliance programs	-		50,372		21,942		66,806
Plant costs/asset retirement obligations	Over plant lives		45,702		44,131		46,009
Natural gas costs recoverable through rate adjustments	Up to 2 years		25,915		—		55,493
Manufactured gas plant site remediation	-		25,851		26,605		26,127
Taxes recoverable from customers	Over plant lives		12,331		12,198		12,249
Electric fuel and purchased power deferral	Up to 2 years		15,612		—		—
Long-term debt refinancing costs	Up to 36 years		2,453		3,041		2,600
Plant to be retired	-		294		21,072		772
Other	Up to 15 years		8,846		11,430		8,588
			414,433		349,500		447,099
Total regulatory assets			$	573,047	$	565,818	$	619,591
Regulatory liabilities:
Current:
Natural gas costs refundable through rate adjustments	Up to 1 year		$	54,282	$	6,331	$	43,161
Provision for rate refund	Up to 1 year		6,517		1,115		6,866
Cost recovery mechanisms	Up to 1 year		5,642		2,926		6,284
Conservation programs	Up to 1 year		3,576		3,834		2,130
Margin sharing	Up to 1 year		2,869		—		5,243
Taxes refundable to customers	Up to 1 year		1,991		1,513		2,149
Refundable fuel and electric costs	Up to 1 year		1,122		1,179		263
Electric fuel and purchased power deferral	Up to 1 year		746		9,630		—
Other	Up to 1 year		13,370		17,867		4,665
			90,115		44,395		70,761
Noncurrent:
Plant removal and decommissioning costs	Over plant lives		220,519		214,467		220,147
Taxes refundable to customers	Over plant lives		190,850		200,879		193,578
Environmental compliance programs	-		63,746		—		61,941
Cost recovery mechanisms	Up to 18 years		24,269		16,313		21,791
Accumulated deferred investment tax credit	Over plant lives		16,129		13,996		15,740
Pension and postretirement benefits	**		6,044		7,376		6,044
Other	Up to 14 years		1,927		1,638		1,809
			523,484		454,669		521,050
Total regulatory liabilities			$	613,599	$	499,064	$	591,811
Net regulatory position			$	(40,552)	$	66,754	$	27,780

*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.

Regulatory Liabilities

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


	Estimated Recovery or Refund Period as of March 31, 2024	*	March 31, 2024		March 31, 2023		December 31, 2023
			(In thousands)
Regulatory assets:
Current:
Natural gas costs recoverable through rate adjustments	Up to 1 year		$	110,481	$	198,166	$	98,844
Electric fuel and purchased power deferral	Up to 1 year		17,061		3,279		33,918
Conservation programs	Up to 1 year		13,735		8,599		14,425
Environmental compliance programs	Up to 1 year		7,443		1,191		5,525
Cost recovery mechanisms	Up to 1 year		6,454		3,954		9,153
Other	Up to 1 year		3,440		1,129		10,627
			158,614		216,318		172,492
Noncurrent:
Pension and postretirement benefits	**		142,511		143,349		142,511
Cost recovery mechanisms	Up to 25 years		84,546		65,732		85,944
Environmental compliance programs	-		50,372		21,942		66,806
Plant costs/asset retirement obligations	Over plant lives		45,702		44,131		46,009
Natural gas costs recoverable through rate adjustments	Up to 2 years		25,915		—		55,493
Manufactured gas plant site remediation	-		25,851		26,605		26,127
Taxes recoverable from customers	Over plant lives		12,331		12,198		12,249
Electric fuel and purchased power deferral	Up to 2 years		15,612		—		—
Long-term debt refinancing costs	Up to 36 years		2,453		3,041		2,600
Plant to be retired	-		294		21,072		772
Other	Up to 15 years		8,846		11,430		8,588
			414,433		349,500		447,099
Total regulatory assets			$	573,047	$	565,818	$	619,591
Regulatory liabilities:
Current:
Natural gas costs refundable through rate adjustments	Up to 1 year		$	54,282	$	6,331	$	43,161
Provision for rate refund	Up to 1 year		6,517		1,115		6,866
Cost recovery mechanisms	Up to 1 year		5,642		2,926		6,284
Conservation programs	Up to 1 year		3,576		3,834		2,130
Margin sharing	Up to 1 year		2,869		—		5,243
Taxes refundable to customers	Up to 1 year		1,991		1,513		2,149
Refundable fuel and electric costs	Up to 1 year		1,122		1,179		263
Electric fuel and purchased power deferral	Up to 1 year		746		9,630		—
Other	Up to 1 year		13,370		17,867		4,665
			90,115		44,395		70,761
Noncurrent:
Plant removal and decommissioning costs	Over plant lives		220,519		214,467		220,147
Taxes refundable to customers	Over plant lives		190,850		200,879		193,578
Environmental compliance programs	-		63,746		—		61,941
Cost recovery mechanisms	Up to 18 years		24,269		16,313		21,791
Accumulated deferred investment tax credit	Over plant lives		16,129		13,996		15,740
Pension and postretirement benefits	**		6,044		7,376		6,044
Other	Up to 14 years		1,927		1,638		1,809
			523,484		454,669		521,050
Total regulatory liabilities			$	613,599	$	499,064	$	591,811
Net regulatory position			$	(40,552)	$	66,754	$	27,780

*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.