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Desalinization and power plants

The Trib has another story about desalinization in Texas, and reading it brings up a point that I don’t think gets enough attention.

KBH Desalinization Facility

Interest in desalination surged more than a decade ago, when the technology became more efficient and cost-competitive, according to Jorge Arroyo, a desalination specialist with the Texas Water Development Board. But the severe drought of the past two years has triggered extra calls to his office. Texas holds 2.7 billion acre-feet of brackish groundwater — which translates to roughly 150 times the amount of water the state uses annually — in addition to some brackish surface water. The state water plan finalized this year envisions Texas deriving 3.4 percent of its water supply from desalination in 2060. (It is less than 1 percent now.)

Environmentalists argue that desalination is not a silver bullet because it is energy-intensive and requires disposal of the concentrated salts in a way that avoids contaminating fresh water. Texas should first focus on conservation and the reuse of wastewater, said Amy Hardberger, a water specialist with the Environmental Defense Fund.

“What needs to be avoided is the, ‘Oh, we’ll just get more’ mentality,” she said.

But getting more is what many Texans want. Odessa, which draws water from dangerously low surface reservoirs, is considering a desalination plant that could ultimately become bigger than the one in El Paso. (Odessa’s deadline for proposals is next week.)

Separately, a planned power plant near Odessa is studying prices for the technology. John Ragan, the head of Texas operations for NRG Energy, envisions natural gas power plants along the coast that desalinate water overnight when they are not needed for electricity. Residents near the half-full Highland Lakes in Central Texas say that desalination could reduce the water-supply burden on the lakes. Texas Tech University aims to begin wind-powered desalination research later this year, in the West Texas town of Seminole.

See here for previous blogging about desalinization. Coal-fired power plants use a lot of water. Natural gas plants use a lot less than coal plants, though they still use a lot. Renewable energy – wind and solar – pretty much don’t need water at all. See this Texas Water Development Board report about power generation and water usage through the year 2060 for more. Desalinization needs to be part of the mix in Texas – we have more than enough brackish water to supply the entire state – but desalinization requires a lot of power, and power generation, at least as we do it today, requires a lot of water. Everybody understands that greenhouse gas and climate change implications of renewable energy versus coal and gas, but the water use implications are as important. The more we invest in renewable energy the better off we’ll be in more ways than we might think.

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