Solar Two, the latest advance in the use of mirror technology for the conversion of solar energy to electric power, is now operational. Dependent on silver-coated mirrors for the highest possible reflection of sunlight into a heat-absorbing medium, the new system, situated in California, is now supplying electricity sufficient to power 10,000 homes.
Solar Two, near Barstow, in southern California, is the most advanced solar power plant in the world, and incorporates technology first introduced in Solar One, which operated from 1982 to 1988 at the same site.
Solar Two differs from Solar One as a result of its use of molten salt rather than boiling water as the heat collecting medium. With the intensity of 500 suns being reflected from 1,926 silver-coated mirrors, the solar heat reflected from the mirrors heats the plant’s nitrate salt to more than 615C. The scalding hot salt is then piped to boilers, which convert water to steam in order to drive the turbines that generate electricity.
Located in the Mojave Desert, where sunny days are the norm, 82,595 square metres of silver-coated mirrors efficiently reflect solar energy to the tower. Silver, being the most reflective metal (more than 97% of the sun’s energy is reflected), makes a major contribution to the efficiency of the solar-heat collecting system, whose overall efficiency is about 36%.
Solar Two is the final step toward the construction of full-scale commercial plants capable of generating 100 to 200 million watts of electricity and providing a cost effective alternative to oil- and coal-generated power.
Multiple use of these plants will reduce U.S. dependency on imported fossil fuels. Solar plants such as this could become common in sun-saturated parts of the world, particularly in developing countries where silver-coated mirrors could replace the need for expensive fossil fuel.
— The preceding was excerpted from “Silver News,” published by the Washington, D.C.-based Silver Institute.
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