Rooftop solar just a small part of energy solution, experts say

On hot California summer days, it makes all the sense in the world: Harness the power of the sun to cool your home, run your refrigerator and charge your gizmos.
After three years in his Placerville home, Brian Veerkamp decided to join the energy revolution. He had a 6 kilowatt solar array mounted on his roof.
"My wife and I firmly believe that individuals should take responsibility for their power needs," said Veerkamp, chief of the El Dorado Hills Fire Department. "California is one of the better states to do this in because we have lots of sunshine."
Last weekend, the sun's rays produced more energy than the Veerkamp household consumed, so the meter spun backward.
That -- and government subsidies -- helps explain why solar panels are being added to existing homes at a quickening pace.
Utilities also are under pressure not only to prepare for future energy needs, but to replace existing dirty-power plants with cleaner sources. The state requirement is that 20 percent of a utility's power delivery be from alternative sources. That minimum is expected to be 33 percent by 2020.
As a result, ambitious plans are in the works to transmit green energy to urban customers from new wind, solar and geothermal energy farms in remote stretches of Northern California.
But as rural opposition to those plans mounts, critics suggest that rather than stringing thousands of miles of new high-voltage power lines -- affecting property owners along the way -- the state should do what Veerkamp has done and turn every rooftop into a mini-power plant.
But with today's technology and existing utility rules, it's just not possible to replace natural-gas or dirty coal-fired power plants with rooftop solar systems alone, according to energy experts.
"It doesn't seem very realistic that you can avoid reliance on large-scale renewable projects and still meet the 33 percent objective," said Matt Freedman, a staff attorney for The Utility Reform Network (TURN), a watchdog group.
Carol Werner, executive director of the Environmental and Energy Study Institute, a think tank based in Washington, said rooftop solar systems can help meet demand when energy is needed most -- on hot, sunny days -- but reducing that demand also should be aggressively pursued.
"It's always cheaper to reduce your energy demand," Werner said.
California Institute of Technology professor Nathan Lewis said it is possible to meet the country's energy needs with solar systems, but it would be a stretch.
First, Lewis figures, you need a practical way to store the energy. Then, solar panels would have to cover 1.7 percent of the nation's surface area -- roughly the size of the panhandles of Texas and Oklahoma, with a bit of Kansas and Colorado thrown in.
"The good news is this area is pretty lightly populated," he wrote in a 2007 paper.
He suggests that another solar technology -- "solar thermal" -- might be less expensive.
While photovoltaic systems are generally used in home projects, solar-thermal plants are built by the acre.
"It's not an either/or scenario at all. It's an all-of-the-above-and-then-some," said Keely Wachs, a spokesman for BrightSource, an Oakland, Calif.-based developer and operator of large-scale solar plants that recently inked a deal to sell Pacific Gas and Electric Co. 1,310 megawatts of power from seven solar-thermal plants the company plans to build in the deserts of Southern California and Nevada.
Industrial-size solar-thermal plants can collect more of the sun's rays because they follow the sun's path, Wachs said.

(efletcher(at)sacbee.com.)

(Distributed by Scripps Howard News Service, www.scrippsnews.com.)
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