The Public Service Commission voted unanimously Tuesday to require Florida Power & Light Co. to refund $13.9 million, including interest, to customers for costs related to a 2008 outage that left as many as 3 million Floridians without electricity.

That will offset fuel costs for customers next year by about 14 cents a month for those who use about 1,000 kilowatt hours.

About 950,000 Florida homes and businesses, including 596,000 FPL customers, lost power Feb. 26, 2008. The outage lasted several hours and was blamed on an FPL engineer, whose actions accidentally triggered the blackout. The incident tripped off two nuclear units at the Turkey Point plant near Miami, as they are designed to do for safety reasons.

FPL officials had agreed to give customers credit for $2 million in costs for replacement power after the first eight hours of the outage. But they argued that the company should not be responsible for covering millions more for replacement power during the time two nuclear generators were down — 158 hours and 107 hours. They said that would effectively punish the company for investing in nuclear power — a clean, reliable energy supply that does not depend on fossil fuels.

FPL spokesman Mayco Villafana said utility regrets the inconvenience caused to customers by the outage but "singling out nuclear outages ... is neither constructive nor appropriate, particularly at a time when state and federal leaders are attempting to remove impediments to the construction of new nuclear plants."

The Office of Public Counsel, the state's advocate for utility customers, disagreed. It recommended customers receive a $15.9 million refund because they had no control over the outage and they pay for the high cost of nuclear plants, including profits on them.

PSC staffers recommended FPL pay nearly $14 million, including interest and costs accrued when the nuclear generators were down. But they had said FPL should be allowed to charge customers for costs during 27 hours when the utility was making repairs required by the Nuclear Regulatory Commission on one of the nuclear generators.

Federal regulators announced in October that FPL will have to pay a $25 million fine for the blackout. FPL did not admit any wrongdoing but agreed to pay the fine to resolve the issue. In 2008, the commission ordered FPL to refund customers $6 million for another blackout, which was blamed on a utility contractor.

Julie Patel can be reached at 954-356-4667 or jpatel@SunSentinel.com.