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Board authorizes Salton Sea desalinization study

February 22, 2002

The Salton Sea Authority will be evaluating the potential of using desalinization as a means to help stabilize salinity levels at the Salton Sea using energy from Imperial County's geothermal resources.

The authority board Thursday approved negotiations with Cal Energy, the U.S. Bureau of Reclamation and Sephton Water Technology to facilitate the demonstration of a vertical tube evaporator desalinization pilot project along the shore of the sea.

Cal Energy has extensive geothermal operations at the southern edge of the sea near Red Hill.

"Desalinization has been evaluated as a restoration concept for a number of years," said authority president Roy Wilson, a member of the Riverside County Board of Supervisors. "However, it has been rejected as a practical solution, largely because of high energy costs."

However, desalinization costs are becoming more competitive with technological advances, Wilson said.

More than a year ago, Hugo Sephton submitted a proposal to the authority to utilize multi-effect vertical tube evaporation as a method to remove salts from the sea and return distilled water to the sea.

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"Sephton's initial proposal included high energy costs that made the proposal less competitive to other restoration plans," Wilson said.

Sephton then revised his proposal to take advantage of potential thermal energy generated through modified solar evaporation ponds. Subsequent discussions led to Cal Energy's geothermal operations as a thermal energy source, Wilson said.

"The geothermal plants currently release low-pressure, low-heat steam as waste. While this steam is not useful for generating electricity, it can be used as a thermal energy source. With the available steam, the energy costs of multi-effect desalinization drop substantially," he said.

While geothermal energy as a source for desalinization seems promising, "this is no magic bullet," said Tom Kirk, executive director of the Salton Sea Authority.

Full-scale facility capital costs may be similar to in-sea ponds — about $500 million under current inflows. Additionally, disposal of concentrated brines will need to be addressed, just as they will need to be addressed for solar and enhanced evaporator systems.

"Like other potential solutions, desalinization does not fully achieve restoration targets under reduced in-flow scenarios, such as may occur through transfers of water implemented by on-farm conservation," Kirk added.

"However, this presents an excellent opportunity for us to explore other alternatives," he added.

A test of vertical tube evaporation was conducted at the Modesto Energy Co. and also at Southern California Edison's Ontario generating station and Cool Water Generating Station in Daggett.

The Modesto plant was a demonstration facility that was scheduled for demolition and dismantling by the end of January.

Because of the immediate availability of that equipment, Sephton, the Bureau of Reclamation and Salton Sea Authority staffs have discussed the prospects of conducting a pilot project with Cal-Energy representatives.

The Modesto test plant has been dismantled and transported to the Imperial Valley.

Testing the desalinization pilot project at the Salton Sea is expected to cost several hundred thousand dollars, Kirk said. The costs could be borne by a combination of Bureau of Reclamation and Salton Sea Authority funding.

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