Molten salt is the life blood of the 150-megawatt heliostat solar power plant proposed by SolarReserve, a well-funded solar company based in California. The California Public Utility Commission will be reviewing the proposal submitted by SolarReserve subsidiary Rice Solar Power last week. If approved, Rice Solar Energy Project (RSEP) will become the nation's first heliostat power plant tied to the public electrical grid.
Though the technology was created by space-age engineering company United Technology subsidiary Rocketdyne, it is in essence quite simple.
The simple salt mixture (sodium & potassium nitrates) is heated by a circular array of 18,000 billboard-sized mirrors (heliostats) which concentrate the sun's heat onto a single point at the top of a 540 foot tower. The tower circulates the molten salt which, exactly like a coal plant, uses that heat to create electricity through a steam-driven turbine.
Salt is an excellent medium for storing heat so the plant will be able to produce energy after-hours, overcoming what has long been seen as solar energy's greatest shortcoming -- intermittency.
There is expected to be the usual barrage of misinformation (perpetrated by evil enemy #1 the Heartland Institute) about the amount of water which the solar thermal plant will consume. But the company's water use permit will stand for itself -- the SolarReserve plant will use about 1/500 the amount of water of at typical coal plant.
This is the latest in a series of "Big Solar" projects which demonstrate the rapid scaling of solar technologies in the U.S. Just a year ago, a 25 megawatt plant was considered large.
Now, with projects like RSEP in California, the 280 MW Solana project in Arizona, and the 300 MW New Solar Ventures project in New Mexico, solar has hit the big time and that vision of converting the hottest, driest part of the United States into a hot bed of power generation may be near at hand.