Southern California Edison and an Arizona renewables developer sealed a deal for a 1 MW pilot solar-thermal project. If successful, the 20-year contract with Stirling Energy Systems may grow into an unprecedented 500-850 MW solar generating station. Those close to the deal expect the price tag for the resulting energy on a large scale to be reasonable (<i>Circuit<\/i>, August 5, 2005). "At a time of rising fossil-fuel costs and increased concern about greenhouse gas emissions, the Stirling project would provide enough clean power to serve 278,000 homes for an entire year," stated John Bryson, Edison International chair. Edison is keeping the price of energy resulting from the pilot under wraps. "We can say that the price of power in this contract represents a winning bid in such a competitive solicitation and that it will require no state subsidy," said Gil Alexander, Edison spokesperson. The contract must be approved by the California Public Utilities Commission. A day after the agreement was finalized, California Energy Commission member John Geesman said, "Yesterday was a good day for solar energy." Geesman has heavily criticized Edison for dragging its feet on renewables development on grounds that the utility territory holds so much green energy potential. Stirling's solar thermal dishes are expected to occupy several square miles if fully deployed. They use a bank of mirrors to focus the sun's energy on a closed loop of hydrogen gas. The gas drives a piston engine that produces electricity as it heats up and expands. The gas cools after it leaves the cylinders and is recycled in an endless loop as long as the sun is shining. The 1 MW Stirling dish project, which will be built in the desert near Victorville, is expected to demonstrate whether the technology can be expanded from 6 arrays to 40. "Then the contract calls for the full facility to come on line as sections of the plant are completed between 2008 and 2012," Alexander said.