The first draft of a report commissioned by state regulators says one kind of solar power and off-shore wind have great potential as sources of renewable energy in Florida, but land-based wind and another kind of solar have almost no future in the state. ...Land-based wind energy -- now the largest renewable energy source by far in the United States -- does not seem commercially viable in Florida, the report said.

The first draft of a report commissioned by state regulators says one kind of solar power and off-shore wind have great potential as sources of renewable energy in Florida, but land-based wind and another kind of solar have almost no future in the state.

The report from Navigant Consulting is a key document commissioned by the Public Service Commission to help regulators and legislators decide how much renewable energy utilities should be required to provide in order to reduce dependence on foreign oil and the greenhouse gases that lead to global warming.

The draft discusses renewable potential but does not detail the costs, which will ultimately be paid for by the consumer. The consulting firm is expected to release estimates about costs next week.

Navigant's report says that solar photovoltaic -- cells that produce electricity directly from sunlight -- have the technical potential to produce more than 200,000 gigawatts of power in Florida by the year 2020 if hundreds of thousands of residential and commercial rooftops are used, as well as large ground-based solar fields.

A gigawatt is 1,000 megawatts. The new Turkey Point nuclear reactors are expected to produce 2,200 megawatts of power when they start operating in a decade or so. The theoretical potential of solar could be considerably greater than that.

Offshore wind in Florida also has huge potential -- technically capable of producing more than 150,000 gigawatts by 2020. Biomass -- power that comes from such materials as wood chips, sugar cane waste and garbage -- has the potential for more 100,000 megawatts, the report asserts.

Two other potential renewable resources, however, were largely dismissed by the Navigant researchers.

Land-based wind energy -- now the largest renewable energy source by far in the United States -- does not seem commercially viable in Florida, the report said.

''To date, no Class 3 regimes, which are generally the minimum for economically viable wind farms, have been identified,'' Navigant says.

Also not viable here is concentrating solar power, the system of mirrors used to heat water or some other liquid, which in turn powers generators. This kind of power is widely used in California, Arizona and Nevada.

A prime leader of that technology, Ausra, backed by a major Silicon Valley venture capital firm, was named last year as a potential partner of Florida Power & Light to produce solar power in the state, but months later the utility decided to use other technologies.

Concentrating solar power, unlike photovoltaic, needs strong, steady flows of direct sunlight to be efficient, Navigant's report says. Such sunlight is often absent in Florida, meaning stand-alone CSP systems ``will not likely be economically competitive in the time frame of this study.''

John D. Wilson, director of research for the Southern Alliance for Clean Energy, said he welcomed the draft. ''The important results,'' involving costs, ``will be forthcoming in the next phase. Nevertheless, we were encouraged to see a broad, comprehensive and professional examination of renewable energy possibilities in Florida.''

Richard Zambo, who represents the Florida Industrial Cogeneration Association, said the key will be the costs involved. ''Some of these energy sources could be extremely expensive,'' he said.

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