Arizona’s Republican Senator Kyl has stepped in to battle against using Arizona’s sun potential for solar CSP. (He was recently famous for saying publicly that we should extend the two trillion dollar tax cuts for the rich rather than extend the unemployment benefits, during the worst recession since the depression).
Senator Kyl claims that solar CSP uses too much water. The plant he opposes would use 800 gallons per MWh, the same as a Palo Verde nuclear plant. Yet he supports the nuclear plant, and even wants Renewable Energy Standards changed so nuclear power qualifies as “renewable”.
Like that nuclear plant, it would use treated waste water. To supply the proposed solar plant, HVS developers and the city are negotiating a contract to sell at least 1 million gallons of effluent per day to the Hualapai Valley Solar project.
Nuclear plants in Arizona are paying a premium to buy waste water at $300 an acre-foot from wastewater treatment facilities to cool nuclear plants. It usually goes for landscaping and golf courses for just $53 an acre-foot.
Water usage ranges widely among the different solar technologies. A water-cooled parabolic trough plant uses up to about 800 gal/MWh. Dish-engine Stirling systems only require about 20 gal/MWh. By contrast, natural gas plants take about 200 gal/MWh, and coal and nuclear plants take 500 to 800 gallons of water/MWh.
Coal and nuclear plants and natural gas plants have not been required to make power without using water, nor have they had to undergo environmental reviews challenging their water use.
Mark Mehos, CSP program manager at the National Renewable Energy Laboratory, told Energy Prospects. “it’s understandable to open the debate,” but he warned against “putting up too many hurdles early” in the development of a technology.
“In Arizona, like in California, if they require CSP not to use water, they should make sure conventional plants have the same type of restrictions,” Mehos said.
Arizona solar has the nation’s greatest potential, and so it will likely remain a net energy supplier to other states of solar power. Solar is premium in deserts. But nuclear plants do not similarly need to be sited in deserts. (Indeed, most nuclear plants are built near rivers or the ocean, to access water for cooling).
Yet, Senator Kyl has never objected to the same water used by the nuclear project in the desert. Indeed, he asks that nuclear power be included in any nationwide renewable energy standard to supply other states with the energy exports that he decries.
“Placing additional demands on Arizona’s water supply in order to export “renewable energy” to other states that have greater energy demands is unsustainable.”
Yet, placing far higher demands on Arizona’s water to export agricultural products never found disfavor with the Senator, as commissioner Paul Newman of the ACC points out.
Arizona’s agriculture that uses 75% of the state’s water, and most of the crops grown with that water gets exported to other states. That uses far more water. For example, Abengoa’s Solana solar project is planned for agricultural land.
It will use an estimated 920 gallons of water per megawatt-hour produced, or about 3,000 acre-feet per year. That compares with the roughly 27,000 acre-feet per year the farming operation used.