Two solar-thermal electric projects that could be built out to massive proportions could be approved by regulators before the end of the year, according to the developer. This is despite the lack of a site for building the initial projects and an expected lack of transmission to get the electricity produced to consumers. \t San Diego Gas & Electric and Stirling Energy systems announced September 7 a 20-year contract to first purchase a minimum of 300 MW from a facility housing 12,000 Stirling solar dishes on about three square miles in Imperial Countys valley desert. In August, Stirling announced a 20-year contract with Southern California Edison to purchase 500 to 850 MW of solar power. That project site is in the Mojave Desert near Victorville. The initial 500 MW phase is planned to include a 20,000-dish array, with an estimated construction period of four years. However, the utility is starting with a 1 MW pilot project. "We have four sites we've been looking at" for the SDG&E development, said Stirling chief executive officer Bruce Osborn. "We're close, but we?re still looking." It will likely be several months before a site is determined, he said. Osborn said he expects approval for the Edison project to come possibly next month and for the SDG&E project a few months later. Power generation would begin by the summer of 2008, said Jim Avery, SDG&E vice-president of electrical operations. The contracts with both SDG&E and Edison have Stirling building the power plants. In San Diego's case, the utility is to supply the power lines. "They'll upgrade [existing] lines, or build new lines and maintain them," Osborn said. For Edison, the utility "has lines in the general area, but we will look to upgrade them," said Gil Alexander, Edison spokesperson. The Imperial Valley, which borders San Diego to the east, is known for its scorching temperatures and sparse rainfall. It was selected by Stirling because of its natural resources and remoteness. "It's an exceptional solar resource," Osborn said. "When we looked at the San Diego region . . . it"s extremely expensive and has coastal weather conditions" that aren"t conducive to solar operations. "Imperial County has great solar resources. It's a natural fit." It's also closer to Stirling's main offices in the Phoenix area, and its remoteness reduces chances of NIMBYism, Osborn said. In addition to the initial 300 MW, SDG&E has options on two future phases that could add an additional 600 MW of renewable energy and capacity to SDG&E's resource mix. The projects would enable Edison and SDG&E to each gain ground on their state-mandated goals of obtaining 20 percent renewable power. SDG&E's renewables currently total 5.5 percent of the utility's portfolio of power supplies. This project would increase that number to 9 percent. If SDG&E picks up its two 300 MW options, expanding the project to 900 MW, SDG&E's renewables would rise to 17 percent of its total generating capacity. When complete, the SDG&E project is expected to provide 30 times more solar power than the entire current solar capacity in the San Diego region. Although Stirling has had recent success in winning contracts with Southern California utilities, the commercial electricity community has only recently begun to embrace its technology. This is despite Stirling's solar technology being tested for more than 20 years. So why now? Osborn said several factors have played into this. "People are becoming much more aware of the environmental aspects of power generation; there have been new state and federal standards; and the industry has become more progressive," according to Osborn. "With the technology improvements and the cost going down, solar generation is becoming more competitive with conventional generation." These are also among the reasons why no government subsidies are needed to fund the project. In addition, costs are offset by the high volume of solar dishes produced, Osborn said. Stirling declined to reveal the cost of the engines or how much money it will take to build the solar plant. Stirling solar dishes, which are about 37 feet in diameter, would be used in an array to focus the sun?s rays on an engine. The engines themselves have four sealed cylinders that contain hydrogen or helium. When a cylinder is heated by the sun, the gas expands and pushes a piston; when it cools, the piston retreats. The mechanical action turns a generator and produces electricity. Because the cylinders are sealed, Stirling engines don't produce emissions. The entire energy conversion process takes place within a canister the size of an oil barrel; it doesn't require water, and the engine is emission-free. It uses a mirror array to focus the sun's rays on the receiver end of a Stirling engine.