Asset Retirement Obligations

12 Months Ended

Dec. 31, 2022

Asset Retirement Obligation Disclosure [Abstract]

In 2022, APS did not revise any cost estimates related to existing AROs, and no new AROs were necessary.

In 2021, APS revised its cost estimates for existing AROs at Cholla related to updated estimates for the closure of ponds and facilities, which resulted in an increase to the ARO of approximately $28 million. See additional details in Notes 3 and 10.

The following table shows the change in our AROs (dollars in thousands):


	2022		2021
Asset retirement obligations at the beginning of year	$	767,382	$	705,083
Changes attributable to:
Accretion expense	41,240		38,437
Settlements	(10,860)		(4,111)

Estimated cash flow revisions	—		27,973
Asset retirement obligations at the end of year	$	797,762	$	767,382

In accordance with regulatory accounting, APS accrues removal costs for its regulated utility assets, even if there is no legal obligation for removal. See detail of regulatory liabilities in Note 3.