Florida's largest investor owned utility announced plans Monday to build three new solar farms that would nearly double the state's solar capacity.

In its announcement, Florida Power & Light said it had found a "cost-effective" way to expand solar power in Florida and proposed to install the systems at three sites in its service area. The utility proposes to add 225 megawatts of solar to the state's current 229 megawatts by the end of next year in Manatee, DeSoto and Charlotte counties.

FPL is still refining the details of the project so the utility did not provide cost estimates. But the company said there would be no significant impact on customer rates.

"Over the past decade, we have continuously focused on advancing reliable, affordable, clean energy for our customers," said Eric Silagy, president and CEO of FPL. "In particular, we have been working especially hard to find ways to advance solar energy in Florida without increasing electricity costs, and we have developed what we believe will be a cost-effective plan.

But FPL utility noted in a news release that "solar power — even the most economical large-scale installation — is generally not yet cost effective in FPL's service area."

That refrain has been part of Duke Energy Florida's argument against any immediate deployment of solar power in its service area, though the utility also has been exploring possible sites in Pinellas County for a solar farm.

Tampa Electric is exploring solar with a project that is just 1 percent the size of FPL's project. Tampa Electric plans to build and operate its solar facility at Tampa International Airport.

The announcement comes as pressure mounts on Florida's utilities and on Tallahassee from grass roots organizations that are calling on the Sunshine State to live up to its name by tapping the sun for more of its electricity needs.

Floridians for Solar Choice — a coalition of tea party and Christian Coalition conservatives as well as liberals, environmentalists and retailers — has launched a petition drive to add an initiative to the 2016 ballot that would allow those who generate electricity from the sun to sell the power directly to other consumers.

That would create competition for the investor owned utilities such as FPL, Duke Energy Florida, Tampa Electric and Gulf Power.

Environmentalists on Monday applauded FPL's efforts after long, heated battles with the utility before state regulators. But they questioned the utility's continued argument that solar is generally not economical.

"The Southern Alliance for Clean Energy disagrees with FPL's assessment that large-scale installations are 'generally not yet cost effective in FPL's service area,' particularly as utility-scale solar has proven to be cost effective in other states and utility territories," said Stephen Smith, the organization's executive director.

"Unfortunately, FPL has not made any of its competitive bids for solar projects public, so it is impossible to know why FPL is making this claim," Smith said. "We welcome more transparency in this round of solar projects and believe competitive bids would bring the most cost-effective solar to Florida ratepayers."

FPL, the nation's third largest electric utility with 4.7 million customers, currently operates 110 megawatts of solar power that it built in 2009 and 2010. At the time they came online, those solar farms made Florida the second largest solar power-producing state in the country.

But Florida has since fallen in rank, now standing at 13th nationwide, according to the Solar Energy Industries Association. The Sunshine State ranks below such states as New Jersey and North Carolina in solar installations. California is by far the nation's leader when it comes to solar power.

A nationwide solar boom has in part been fueled by a 30 percent federal tax credit that will decrease to 10 percent at the end of 2016. By that time, FPL expects to have its new solar farms up and running.

Because of the size and "cost-effectiveness" of the project, FPL does not need approval from state regulators in advance of building the solar power plants, said utility spokesman Mark Bubriski. But the Public Service Commission will review any costs passed onto customers.

Florida's investor owned utilities have argued that solar is too costly and that there are too many clouds for solar to be effective in Florida without a way to store power for times of low radiance or at night.

But in the last week, the utilities have proposed bigger solar projects than the state has ever produced.

Gulf Power, a subsidiary of Georgia-based Southern Co., plans to add 120 megawatts of solar power at military bases on the Florida Panhandle.

"At first blush, it's like, 'Wow! This is great news,' " said Ken Johnson, spokesman for the Solar Energy Industries Association in Washington, D.C. "But as a state, (Florida) is just scratching the surface of its potential in regard to solar."

Contact Ivan Penn at ipenn@tampbay.com or (727) 892-2332. Follow @Consumers_Edge.