The $14 billion expansion project at Plant Vogtle is set to begin construction in 2011 and is scheduled to be completed in 2017. The PSC voted 4-1 Tuesday to certify the proposal from Georgia Power, a subsidiary of Southern Co. The U.S. Nuclear Regulatory Commission must also sign off.

Supporters called the proposed expansion a "green" alternative to meet the state's growing energy needs.

"It is clean. It is safe and it has become the least expensive form of (power) generation in our state," Commissioner Stan Wise said.

But critics questioned where the waste would be stored and how the project would affect the Savannah River basin.

"Given the financial, security and safety risks with nuclear power, this PSC decision will result in a poor use of ratepayers' money," said Rita Kilpatrick, Georgia policy director for the Southern Alliance for Clean Energy.

Still, Tuesday's debate at the PSC centered on questions of financing. Included in the plan passed Tuesday was a financing scheme that would allow Georgia Power to begin to collect some $1.6 billion in costs from ratepayers six years before the reactors go online.

That means ratepayers would see their electric bill rise by an average of $1.30 a month in 2011. Those rates will gradually rise until customers see an additional $9.10 a month on their bill in 2017.

Supporters said rates would go up to pay for expansion either way. They said the financing plan eases the rate increase in gradually, rather than having customers see their bills jump sharply once construction is done.

PSC staff had recommended that the commission hold off on approving the financing plan until the panel considers Georgia Power's separate request for a rate increase next year.

Commissioner Bobby Baker said the current economic uncertainty begs for more information.

"I think you all are taking a big gamble with the Georgia Power company's money, with the ratepayers' money to make the decision today without the best information," Baker said.

Baker said Georgia Power would not begin to recoup the costs until 2011.

"We don't need to make this decision today," Baker said. He cast the lone dissenting vote.

Wise countered that the financing plan would shave about $300 million off the price tag.

The financing plan the PSC adopted Tuesday mirrors a plan the Legislature adopted last month. The bill was heavily lobbied at the state Capitol this session. Georgia Power signed on a fleet of top lobbyists to push the measure. Consumer groups enlisted advocate Clark Howard, who bashed the bill as bad for ratepayers. It was one of the first significant pieces of legislation to clear both chambers this year.

Gov. Sonny Perdue plans to sign the bill, a spokesman said Tuesday.

Perdue's chief of staff, Ed Holcomb, is Georgia Power's former chief lobbyist.

Georgia Power officials said legislative and PSC approval of the financing measure gave them an additional level of security as they moved forward to secure funding on the pricey expansion.

The first step in the federal review by the Nuclear Regulatory Commission has already begun. A decision on Georgia Power's request for an early site permit could come by the year's end.

NRC spokesman Roger Hannah said the last new nuclear reactor to begin construction was Tennessee's Watts Bar plant in the 1970s. Some 17 applications currently are pending before the NRC, all of them filed in the past two years.