Asset Retirement Obligations

6 Months Ended

Mar. 31, 2019

Asset Retirement Obligation Disclosure [Abstract]

During the six months ended March 31, 2019, TVA's total asset retirement obligations ("ARO") liability increased $198 million as a result of revisions in estimates and periodic accretion, partially offset by settlement activity from ongoing ARO projects at TVA facilities. The nuclear and non-nuclear accretion amounts were deferred as regulatory assets. During the six months ended March 31, 2019, $72 million of the related non-nuclear regulatory assets were amortized into expense as these amounts were collected in rates. See Note 7. TVA maintains investment trusts to help fund its decommissioning obligations. See Note 15 — Investment Funds and Note 19 — Contingencies — Decommissioning Costs for a discussion of the trusts' objectives and the current balances of the trusts.



Asset Retirement Obligation Activity⁽¹⁾
	Nuclear		Non-Nuclear			Total
Balance at September 30, 2018	$	2,989	$	1,790		$	4,779
Settlements	—		(42		)	(42		)
Revisions in estimate	—		136			136
Additional Obligation	14		—			14
Accretion (recorded as regulatory asset)	67		23			90
Balance at March 31, 2019	$	3,070	$	1,907		$	4,977

Note

(1) The current portion of ARO in the amount of $102 million and $115 million is included in Accounts payable and accrued liabilities at March 31, 2019, and September 30, 2018, respectively.

As a result of recent experience in completing settlements at certain facilities, the revisions in non-nuclear estimates increased $103 million primarily due to expected costs for asbestos abatement activities across TVA's fossil fleet. In addition, TVA approved a change in the preferred closure method for the Allen West Impoundment from closure in place to closure by removal, which resulted in a cost increase of $33 million.