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First In U.S.: Electricity From Solar Pond

October 15, 1986

EL PASO, Texas (AP) _ Solar energy heating a pond of salt water was used to generate electricity Wednesday in what scientists called the first such power system in this country.

The solar pond heat storage and power system works on simpler technology than a photovoltaic plant which uses silicon cells to produce electricity directly from sunlight.

″One advantage over photovoltaic is this comes with its own storage,″ said Robert Reid, project manager and chairman of the Mechanical and Industrial Engineering Department at the University of Texas-El Paso.

″We can generate electricity 24 hours a day,″ he added. ″We can go for weeks or even months without any sun.″

The sun heats a layer of salt water at the bottom of the pond. That dense salt water is covered by a layer of lighter fresh water, which serves as insulation to prevent the heat from escaping into the air.

The hot salt water is used to boil Freon, turning it into a gas that propels a turbine, which in turn spins a electrical generator.

Solar ponds were developed in Israel. The El Paso solar pond is the first to produce electricity in this country, said Stan Hightower of the U.S. Bureau of Reclamation.

The 0.83-acre pond is at the Bruce Foods Corp. canning plant in the outskirts of this border city. It will produce 100 kilowatts of electricity ″or approximately enough energy to serve 10 households a year,″ said Reid.

He estimated that energy from the solar pond will save Bruce Foods $20,000 in electric bills a year.

Last year, the pond became the first in the world to provide industrial process heat, needed by Bruce Foods in its canning operation, Reid said.

A second function of the solar pond - desalination of water - is expected to begin operating in 1987, another first in the United States, he said.

The El Paso project was begun 3 1/2 years ago as a joint effort by the university, the Bureau of Reclamation, Bruce Foods and El Paso Electric Corp.

″Solar ponds are a world technology,″ Reid said. ″They are low-cost ... you dig a hole in the ground, put a (water) line in and throw some salt in.″

The pond has a capacity of two million gallons of water and needed 1,700 tons of salt, donated by the U.S. Department of Energy’s nuclear waste disposal site being carved out of salt beds near Carlsbad, N.M., said Hightower.

In areas of abundant sunshine, such as the Southwest, solar-heated water is an alternative to burning coal or other fuels to drive a turbine-genera tor, Reid said.

Israel has a 60-acre solar pond at the Dead Sea in operation since 1983 which produces 5,000 kilowatts, Reid said. Another solar pond plant in Australia generates only 25 kilowatts.

″The Israelis consider their technology fairly confidential,″ said Reid. ″We talked to the Israelis and they would tell us things only verbally.″

Equipment used with the pond was made in Israel by Ormat Systems Inc., whose president was at Wednesday’s ceremony.

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