Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2020

Asset Retirement Obligation Disclosure [Abstract]

Reconciliation of Asset Retirement Obligations

A reconciliation of the ARO liabilities is as follows:


	PNMR		PNM		TNMP
	(In thousands)
Liability at December 31, 2017	$	146,679	$	145,707	$	793
Liabilities incurred	—		—		—
Liabilities settled	(192)		—		—
Accretion expense	11,482		11,402		67
Revisions to estimated cash flows	705		705		—
Liability at December 31, 2018	158,674		157,814		860
Liabilities incurred	—		—		—
Liabilities settled	(987)		(935)		(52)
Accretion expense	12,635		12,562		73
Revisions to estimated cash flows(1)	11,640		11,640		—
Liability at December 31, 2019	181,962		181,081		881
Liabilities incurred	—		—		—
Liabilities settled	(1,444)		(1,192)		(252)
Accretion expense	11,310		11,235		75
Revisions to estimated cash flows(2)	(8,407)		(8,407)		—
Liability at December 31, 2020	$	183,421	$	182,717	$	704

(1) Reflects the impacts of an updated SJGS decommissioning study that assumes PNM will retire its share of SJGS in 2022.

(2) Reflects a decrease of $9.2 million related to an updated PVNGS decommissioning study and an increase of $0.8 million related to an updated Four Corners decommissioning study.