Regulatory assets and liabilities (Tables)

6 Months Ended

Jun. 30, 2023

Regulatory Assets and Liabilities Disclosure [Abstract]

Regulatory Assets

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

	Estimated Recovery or Refund Period as of June 30, 2023	*	June 30, 2023		June 30, 2022		December 31, 2022
			(In thousands)
Regulatory assets:
Current:
Natural gas costs recoverable through rate adjustments	Up to 1 year		$	170,249	$	83,557	$	141,306
Conservation programs	Up to 1 year		10,897		7,883		8,544
Cost recovery mechanisms	Up to 1 year		4,758		3,459		4,019
Other	Up to 1 year		7,258		7,636		11,223
			193,162		102,535		165,092
Noncurrent:
Pension and postretirement benefits	**		144,448		137,582		143,349
Cost recovery mechanisms	Up to 10 years		63,890		64,096		67,171
Plant costs/asset retirement obligations	Over plant lives		43,855		63,334		44,462
Manufactured gas plant site remediation	-		25,764		26,031		26,624
Plant to be retired	-		20,858		27,628		21,525
Environmental compliance programs	-		20,611		—		—
Taxes recoverable from customers	Over plant lives		12,099		12,365		12,330
Long-term debt refinancing costs	Up to 37 years		2,894		3,482		3,188
Other	Up to 16 years		10,766		12,543		11,010
			345,185		347,061		329,659
Total regulatory assets			$	538,347	$	449,596	$	494,751
Regulatory liabilities:
Current:
Natural gas costs refundable through rate adjustments	Up to 1 year		17,820		738		955
Electric fuel and purchased power deferral	Up to 1 year		8,481		4,161		4,929
Cost recovery mechanisms	Up to 1 year		3,304		3,172		1,977
Conservation programs	Up to 1 year		2,851		352		4,126
Taxes refundable to customers	Up to 1 year		1,513		3,728		3,937
Refundable fuel and electric costs	Up to 1 year		103		1,092		3,253
Other	Up to 1 year		13,985		4,641		7,263
			48,057		17,884		26,440
Noncurrent:
Plant removal and decommissioning costs	Over plant lives		216,682		172,755		208,650
Taxes refundable to customers	Over plant lives		197,757		209,022		203,222
Cost recovery mechanisms	Up to 19 years		18,226		10,898		14,025
Accumulated deferred investment tax credit	Up to 19 years		14,398		14,009		13,594
Pension and postretirement benefits	**		7,120		19,686		7,376
Other	Up to 15 years		1,694		6,649		1,587
			455,877		433,019		448,454
Total regulatory liabilities			$	503,934	$	450,903	$	474,894
Net regulatory position			$	34,413	$	(1,307)	$	19,857

*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, 2023	*	June 30, 2023		June 30, 2022		December 31, 2022
			(In thousands)
Regulatory assets:
Current:
Natural gas costs recoverable through rate adjustments	Up to 1 year		$	170,249	$	83,557	$	141,306
Conservation programs	Up to 1 year		10,897		7,883		8,544
Cost recovery mechanisms	Up to 1 year		4,758		3,459		4,019
Other	Up to 1 year		7,258		7,636		11,223
			193,162		102,535		165,092
Noncurrent:
Pension and postretirement benefits	**		144,448		137,582		143,349
Cost recovery mechanisms	Up to 10 years		63,890		64,096		67,171
Plant costs/asset retirement obligations	Over plant lives		43,855		63,334		44,462
Manufactured gas plant site remediation	-		25,764		26,031		26,624
Plant to be retired	-		20,858		27,628		21,525
Environmental compliance programs	-		20,611		—		—
Taxes recoverable from customers	Over plant lives		12,099		12,365		12,330
Long-term debt refinancing costs	Up to 37 years		2,894		3,482		3,188
Other	Up to 16 years		10,766		12,543		11,010
			345,185		347,061		329,659
Total regulatory assets			$	538,347	$	449,596	$	494,751
Regulatory liabilities:
Current:
Natural gas costs refundable through rate adjustments	Up to 1 year		17,820		738		955
Electric fuel and purchased power deferral	Up to 1 year		8,481		4,161		4,929
Cost recovery mechanisms	Up to 1 year		3,304		3,172		1,977
Conservation programs	Up to 1 year		2,851		352		4,126
Taxes refundable to customers	Up to 1 year		1,513		3,728		3,937
Refundable fuel and electric costs	Up to 1 year		103		1,092		3,253
Other	Up to 1 year		13,985		4,641		7,263
			48,057		17,884		26,440
Noncurrent:
Plant removal and decommissioning costs	Over plant lives		216,682		172,755		208,650
Taxes refundable to customers	Over plant lives		197,757		209,022		203,222
Cost recovery mechanisms	Up to 19 years		18,226		10,898		14,025
Accumulated deferred investment tax credit	Up to 19 years		14,398		14,009		13,594
Pension and postretirement benefits	**		7,120		19,686		7,376
Other	Up to 15 years		1,694		6,649		1,587
			455,877		433,019		448,454
Total regulatory liabilities			$	503,934	$	450,903	$	474,894
Net regulatory position			$	34,413	$	(1,307)	$	19,857

*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.