Israel uses Dead Sea to harness sun

At this farthest point from the sun on the face of the earth, Israel has launched the most ambitious project yet undertaken to harness solar energy. Land-clearing operations began recently on the shores of the Dead Sea -- more than 400 meters below sea level -- for a quarter-of-a-kilometer-square pool whose saline waters will hopefully begin to produce five megawatts of electricity within two years.

The engineers in charge of the project believe that this solar pool, and others like it, will be producing 2,000 megawatts of energy -- 20 percent of Israel's anticipated energy needs -- by the turn of the century.

Israel is several years ahead of the rest of the world in this aspect of solar technology, and energy officials here expect worldwide application for this fuel- free energy source.

Conceived by Hebrew University Prof. Zvi Tabor, the solar pond is a shallow pool with a dark bottom whose lower depths are heated by the sun. To prevent the heated water from rising to the top, the lower layers are infused with salt to make them heavier than the water at the top.

As temperatures build up in the lower levels to more than 80 degrees C., the water is carried off by pipes to locally developed low-temperature turbines capable of producing steam even at 70 degrees C.

An experimental pond has been operating successfully on the shores of the Dead Sea since 1978, a two-acre pool producing 150 kilowatts of electricity.

The intense sunlight and the ample supply of saline water make the area -- lowest point on the surface of the earth -- ideal for solar pools. If the poll now being built proves successful, it will become a standardized module size which will be multiplied according to the space available.

Plans already exist for linking it to three other modules to form a kilometer- square pool producing 20 megawatts by 1985.

Solar ponds are a joint venture of the government -- which is putting up 80 percent of the funding -- the academic world, and private industry.

The company developing the ponds, Solmat, was created by Hebrew University and a private company headed by Yehuda Bronicki, who used to work in Professor Tabor's laboratory before turning to the manufacture of turbines. Mr. Bronicki is the driving force behind the project and Solmat's director- general.

"From the data we've accumulated in the pilot plant," says Mr. Bronicki, "I'm convinced we can build ponds which will supply a substantial portion of the country's energy needs."

The head of an Israeli industrial investment company, Yosef Vardi, recently challenged the viability of the solar pond on the grounds of the high investment required. In response, Mr. Bronicki says viability has indeed not been achieved yet, but that it will be.

Meanwhile, Israel will be reducing its dependency on imported oil, and the political debts that go with such dependency, as it makes use of the one natural resource it has in abundance -- sunlight.

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