Regulatory assets and liabilities (Tables)

6 Months Ended

Jun. 30, 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 June 30, 2024	*	June 30, 2024		June 30, 2023		December 31, 2023
			(In thousands)
Regulatory assets:
Current:
Natural gas costs recoverable through rate adjustments	Up to 1 year		$	105,064	$	170,249	$	98,844
Environmental compliance programs	Up to 1 year		84,486		2,926		5,525
Conservation programs	Up to 1 year		15,713		10,897		14,425
Cost recovery mechanisms	Up to 1 year		6,074		4,758		9,153
Electric fuel and purchased power deferral	Up to 1 year		3,024		2,221		33,918
Other	Up to 1 year		3,461		2,111		10,627
			217,822		193,162		172,492
Noncurrent:
Pension and postretirement benefits	**		142,511		144,448		142,511
Cost recovery mechanisms	Up to 25 years		82,984		63,890		85,944
Plant costs/asset retirement obligations	Over plant lives		45,342		43,855		46,009
Manufactured gas plant site remediation	-		25,704		25,764		26,127
Natural gas costs recoverable through rate adjustments	Up to 2 years		15,870		—		55,493
Taxes recoverable from customers	Over plant lives		12,311		12,099		12,249
Electric fuel and purchased power deferral	Up to 2 years		12,160		—		—
Environmental compliance programs	-		2,858		20,611		66,806
Long-term debt refinancing costs	Up to 36 years		2,306		2,894		2,600
Plant to be retired	-		227		20,858		772
Other	Up to 15 years		9,061		10,766		8,588
			351,334		345,185		447,099
Total regulatory assets			$	569,156	$	538,347	$	619,591
Regulatory liabilities:
Current:
Environmental compliance programs	Up to 1 year		$	72,644	$	—	$	—
Natural gas costs refundable through rate adjustments	Up to 1 year		60,400		17,820		43,161
Provision for rate refund	Up to 1 year		7,767		1,227		6,866
Cost recovery mechanisms	Up to 1 year		3,841		3,304		6,284
Conservation programs	Up to 1 year		3,330		2,851		2,130
Margin sharing	Up to 1 year		2,188		1,791		5,243
Taxes refundable to customers	Up to 1 year		2,074		1,513		2,149
Refundable fuel and electric costs	Up to 1 year		1,431		103		263
Electric fuel and purchased power deferral	Up to 1 year		506		8,481		—
Other	Up to 1 year		4,354		10,967		4,665
			158,535		48,057		70,761
Noncurrent:
Plant removal and decommissioning costs	Over plant lives		222,668		216,682		220,147
Taxes refundable to customers	Over plant lives		187,827		197,757		193,578
Cost recovery mechanisms	Up to 18 years		26,286		18,226		21,791
Accumulated deferred investment tax credit	Over plant lives		16,518		14,398		15,740
Pension and postretirement benefits	**		6,043		7,120		6,044
Environmental compliance programs	-		—		—		61,941
Other	Up to 14 years		2,024		1,694		1,809
			461,366		455,877		521,050
Total regulatory liabilities			$	619,901	$	503,934	$	591,811
Net regulatory position			$	(50,745)	$	34,413	$	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 June 30, 2024	*	June 30, 2024		June 30, 2023		December 31, 2023
			(In thousands)
Regulatory assets:
Current:
Natural gas costs recoverable through rate adjustments	Up to 1 year		$	105,064	$	170,249	$	98,844
Environmental compliance programs	Up to 1 year		84,486		2,926		5,525
Conservation programs	Up to 1 year		15,713		10,897		14,425
Cost recovery mechanisms	Up to 1 year		6,074		4,758		9,153
Electric fuel and purchased power deferral	Up to 1 year		3,024		2,221		33,918
Other	Up to 1 year		3,461		2,111		10,627
			217,822		193,162		172,492
Noncurrent:
Pension and postretirement benefits	**		142,511		144,448		142,511
Cost recovery mechanisms	Up to 25 years		82,984		63,890		85,944
Plant costs/asset retirement obligations	Over plant lives		45,342		43,855		46,009
Manufactured gas plant site remediation	-		25,704		25,764		26,127
Natural gas costs recoverable through rate adjustments	Up to 2 years		15,870		—		55,493
Taxes recoverable from customers	Over plant lives		12,311		12,099		12,249
Electric fuel and purchased power deferral	Up to 2 years		12,160		—		—
Environmental compliance programs	-		2,858		20,611		66,806
Long-term debt refinancing costs	Up to 36 years		2,306		2,894		2,600
Plant to be retired	-		227		20,858		772
Other	Up to 15 years		9,061		10,766		8,588
			351,334		345,185		447,099
Total regulatory assets			$	569,156	$	538,347	$	619,591
Regulatory liabilities:
Current:
Environmental compliance programs	Up to 1 year		$	72,644	$	—	$	—
Natural gas costs refundable through rate adjustments	Up to 1 year		60,400		17,820		43,161
Provision for rate refund	Up to 1 year		7,767		1,227		6,866
Cost recovery mechanisms	Up to 1 year		3,841		3,304		6,284
Conservation programs	Up to 1 year		3,330		2,851		2,130
Margin sharing	Up to 1 year		2,188		1,791		5,243
Taxes refundable to customers	Up to 1 year		2,074		1,513		2,149
Refundable fuel and electric costs	Up to 1 year		1,431		103		263
Electric fuel and purchased power deferral	Up to 1 year		506		8,481		—
Other	Up to 1 year		4,354		10,967		4,665
			158,535		48,057		70,761
Noncurrent:
Plant removal and decommissioning costs	Over plant lives		222,668		216,682		220,147
Taxes refundable to customers	Over plant lives		187,827		197,757		193,578
Cost recovery mechanisms	Up to 18 years		26,286		18,226		21,791
Accumulated deferred investment tax credit	Over plant lives		16,518		14,398		15,740
Pension and postretirement benefits	**		6,043		7,120		6,044
Environmental compliance programs	-		—		—		61,941
Other	Up to 14 years		2,024		1,694		1,809
			461,366		455,877		521,050
Total regulatory liabilities			$	619,901	$	503,934	$	591,811
Net regulatory position			$	(50,745)	$	34,413	$	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.