Florida Power & Light Co. and real estate developer Kitson & Partners to build what the two companies said would be the world's largest solar photovoltaic power plant.

The plant will come up at be at Babcock Ranch, Florida, a planned new city south of the Tampa Bay area and east of Fort Myers. The city of Babcock Ranch is planned to include 6-million square feet of retail, commercial, office, civic and light industrial space, and would be the world's first city powered by solar energy.

''We're out to prove that it works economically,'' developer Syd Kitson told the press. ''And it's the right thing to do for the long-term solutions in this country.''

The 17,000-acre city will consume less power than the proposed Florida Power & Light on-site solar facilities will produce, allowing it to become the first city powered by zero-emission solar energy. The city also will be home to an integrated ''smart grid'' that will allow residents and businesses to monitor and control their energy consumption.

The solar panels will sit on 350 acres within the development. More than half of the city's 17,000 acres will be permanently protected as greenways and open space, the developer said, and will adjoin the 73,000-acre Babcock Ranch Preserve that has been purchased by the state.

FPL estimates the Babcock solar facility will cost about $300 million and add about 31 cents to the average customer's monthly bill. Among other projects in the years ahead, the company is also working to add 1,200 megawatts of power fueled by natural gas in Palm Beach County and 2,200 megawatts of new nuclear power at Turkey Point.

Juno Beach-based FP&L plans to break ground on the solar facility in late 2009, subject to state of Florida approvals, with construction of the city center targeted for mid-2010 and construction of the first residential and commercial buildings targeted for late 2010, the release said.

The Babcock project was announced in Washington, attended by FPL executives, politicians and environmentalists. ''This is a national story,'' said Kitson, ``and we wanted to get it out to a broader audience. Clean energy and sustainable development are the future of America. This will be a living laboratory for companies, workers and families. And it will create jobs.''

FP&L, a subsidiary FPL Group, provides power for nearly 30 counties in the state of Florida, including Palm Beach, Broward and Miami-Dade. FPL Group shares were down 87 cents to $51.75 in afternoon trading. The 52-week high was $68.98 on 2 May. The 52-week low was $33.81 on 10 October.