Coupling solar energy to natural gas, and hoping for the best of both
INDIANTOWN, Fla. — In former swamplands teaming with otters and wild hogs, one of the nation’s biggest utilities is running an experiment in the future of renewable power.
Across 500 acres north of West Palm Beach, the FPL Group utility is assembling a life-size Erector Set of 190,000 shimmering mirrors and thousands of steel pylons that stretch as far as the eye can see. When it is completed by the end of the year, this vast project will be the world’s second-largest solar plant.
But that is not its real novelty. The solar array is being grafted onto the back of the nation’s largest fossil-fuel power plant, fired by natural gas. It is an experiment in whether conventional power generation can be married with renewable power in a way that lowers costs and spares the environment.
This project is among a handful of innovative hybrid designs meant to use the sun’s power as an adjunct to coal or gas in producing electricity. While other solar projects already use small gas-fired turbines to provide backup power for cloudy days or at night, this is the first time that a conventional plant is being retrofitted with the latest solar technology on such an industrial scale.
The project’s advantages are obvious: Electricity generated from the sun will allow FPL to cut natural gas use and reduce carbon dioxide emissions. It will provide extra power when it is most needed: when the summer sun is shining, Floridians are cranking up their air-conditioning and electricity demand is at its highest.
The plant also serves as a real-life test on how to reduce the cost of solar power, which remains much more expensive than most other forms of electrical generation. FPL Group, the parent company of Florida Power and Light, expects to cut costs by about 20 percent compared with a stand-alone solar facility, since it does not have to build a new steam turbine or new high-power transmission lines.
“We’d love to tell you that solar power is as economic as fossil fuels, but the reality is that it is not,” Lewis Hay III, FPL’s chairman and chief executive, said on a recent plant tour. “We have got to figure out ways to get costs down. As we saw with wind power, a lot has to do with scale.”
For solar power, scale is still a relative term. At its peak, the solar plant will be able to generate 75 megawatts of power, enough for about 11,000 homes. But that is dwarfed by the adjacent gas plant, which can produce about 3,800 megawatts of power. Utilities are being pulled in different directions. They must ensure that the lights remain on at all times as well as provide the lowest-cost power to their customers.