SOUTHERN CALIFORNIA EDISON Co

Key Assumptions and Approach Used. San Onofre Units 1, 2 and 3 decommissioning cost estimates are updated in each NDCTP and when there are material changes to the timing or amount of estimated future cash flows. Palo Verde decommissioning cost estimates are updated by the operating agent, Arizona Public Services, every three years and when there are material changes to the timing or amount of estimated future cash flows. SCE estimates that it will spend approximately $6.1 billion, undiscounted through 2080, to decommission its nuclear facilities.

The current ARO estimates for San Onofre and Palo Verde are based on:

See "Liquidity and Capital Resources—SCE—Decommissioning of San Onofre" for further discussion of the plans for decommissioning of San Onofre.

Effect if Different Assumptions Used. The ARO for decommissioning SCE's nuclear facilities was $2.2 billion as of December 31, 2023, based on the most recent decommissioning studies performed and the subsequent cost estimate updates. Changes in the estimated costs, execution strategy or timing of decommissioning, or in the assumptions and judgments by management underlying these estimates, could cause material revisions to the estimated total cost to decommission these facilities which could have a material effect on the recorded liability.

The following table illustrates the increase to the ARO liability if the cost escalation rate was adjusted while leaving all other assumptions constant:

The increase in the ARO liability driven by an increase in the escalation rate would result in a decrease in the regulatory liability for recoveries in excess of ARO liabilities.