The Public Utilities Commission is reviewing Solaren's contract with PG&E, a unit of PG&E Corp. Regulators are charged with ensuring that the deal helps the utility meet a requirement to get one-fifth of its power from renewable sources by 2012. PG&E has asked for a ruling before Oct. 29.
Consumer advocates and more Earth-bound proponents of renewable energy are extremely skeptical.
California will be unable to meet its looming 20% renewable energy requirement, let alone a more ambitious 30% goal by 2030, if utilities and regulators continually embrace expensive, flashy and unproven technologies, they say. Policymakers, instead, should stick with reliable alternative sources -- such as geothermal, wind and centralized solar, sunlight concentrated by mirrors -- that have been operating commercially for decades.
"There are a lot of speculative plays," says V. John White, director of the Center for Energy Efficiency and Renewable Technology in Sacramento. "We have a lot of PowerPoints floating around that I don't think will turn into power plants."
The concept behind space-based solar power is simple, Solaren says.
Four or five rocket launches would be needed to put enough solar collectors into a stationary orbit to produce 200 megawatts of power, about half the output of a modern natural-gas-fired plant. The solar energy would be converted radio waves and beamed to a receiving station in Fresno, leaving unscathed any birds or airplanes that get in the way of the highly diffused beam. There, it would be converted to either alternating or direct electric current and dispatched to customers via high-voltage transmission lines.
Spirnak acknowledges that nothing on this scale has been attempted, but the basic technology is proven. Commercial communications satellites have been powered by solar energy for more than four decades. The satellites use the sun's power, available 24 hours a day in space, to make electricity. The electricity is turned into radio waves to bounce television, telephone and other signals around the globe.
Experience with larger scale, experimental radio transmissions converted to electrical power is limited, PG&E wrote in the regulatory filing. In 1975, NASA's Jet Propulsion Laboratory transmitted 34 kilowatts of energy about a mile. Last year, a former JPL scientist, John Mankins, transmitted a small amount of power generated by ground-based solar cells 92 miles between two Hawaiian islands.
