Despite its nickname, the Sunshine State, Florida's heavy rains and pricey real estate mean it has never been considered a good place to set up big solar energy plants.

So a new initiative by the fourth most-populous U.S. state to get its utilities to generate 20 percent of their power from sun, wind and other renewable resources will mean wiring rooftops rather than building huge solar or wind farms.

Utilities say large solar power plants would simply not be cost effective.

The cloud cover in Florida limits the amount of power that can be produced, said Mayco Villafana, a spokesman for Florida Power & Light, the state's largest electricity company.

But Florida has plenty of sunshine to power rooftop solar panels and renewable energy advocates are urging the state to help residents create thousands of mini power plants in their homes.

Gov. Charlie Crist announced this week that he wants utilities to generate one-fifth of their electricity from renewables to combat global warming -- joining several other states that have adopted measures to reduce greenhouse gases in the absence of action by the federal government.

Crist's executive orders, which he was due to sign at a climate change summit in Miami on Friday, did not contain a target date for the 20 percent goal. State officials could not provide figures on the current share of renewable energy.

But Mike Sole, secretary of the state's Department of Environmental Protection, said on the sidelines of the conference that the target date is 13 years from now.

We are proposing and have recommended to the governor that it be 2020, he said. Now we have to work with the Public Service Commission (regulators) to get that implemented.

Crist's initiative calls on the state to permit people who generate power at their homes and businesses to lower utility bills by feeding excess electricity back into the grid.

SUNSHINE STATE

The American West's vast open spaces provide all the ingredients for alternative energy plants -- vast tracts of cheap desert land, steady winds and year-round sunshine. Florida's expensive real estate, unreliable wind and severe rainy season limit its prospects, according to experts.

FPL Group, the parent of Florida Power & Light, the state's largest utility, is the top U.S. wind power generator with 47 wind farms in 15 states. Yet it does not have one in Florida.

It has a major solar plant in California's Mojave Desert, but none in the Sunshine State, even though Florida has as much sunshine -- 5 to 6 kilowatt hours per meter squared per day -- as parts of California.

We're not look at Arizona-style or Nevada-style solar fields as a primary target, said Sole. We're looking at rooftops.

Photovoltaic systems that collect the sun's rays and turn them into energy can cost $30,000 or more for an average U.S. home, so solar advocates are pushing Florida to expand incentives to help residents with initial costs.

James Fenton, director of the Florida Solar Energy Center, said a monthly charge of $1.50 on a utility bill could raise more than $200 million a year to invest in a panel installation program.

California, which has a Million Solar roofs program under way, puts more than $300 million yearly into installation of solar panels on rooftops.

The utilities have to find a way to own the PV power plant on my roof so they can profit from it, Fenton said.

He said Florida has twice the sunshine of Germany, a global leader in solar power, and believes local utilities are ready to hop on the bandwagon.

They like big power plants, he said. So it's about switching over this mindset from a big power plant to a small one. But I think they are coming around.

Villafana said FPL generally supports Crist's initiative but is taking a wait-and-see attitude until state regulators explain how the plan would work.

Asked if FPL is interested in owning photovoltaic rooftop installations on private homes, he said: We haven't even discussed that.