The California Public Utilities Commission said in a statement Tuesday that the operating costs for the plant were "neither reasonable nor necessary" and are just a portion of what Southern California Edison and San Diego Gas & Electric owe customers.
"The proposed decision is the first in a series that evaluates costs to ensure customers don't pay for both the power plant that was shut down and the power that had to be purchased to replace it," agency Commissioner Mike Florio said. "The CPUC is considering hundreds of millions of dollars in additional refunds to customers."
The proposal recommends that Southern California Edison refund $74.2 million and part-owner San Diego Gas & Electric refund $19.3 million.
The commission will consider the recommendation next month.
A spokeswoman for SoCal Edison said the utility was reviewing the proposal and had no immediate comment. A SDG&E spokeswoman had no immediate comment.
The plant was shut down in January 2012 after a small radiation leak led to the discovery of damaged tubing. Edison closed the plant for good earlier this year.
The Associated Press contributed to this report.