From Greenwire today (sub req’d): water availability may limit new power plants. This is widely appreciated in the power sector, but doesn’t get as much attention elsewhere. It’s especially acute as our population growth moves south and west where we are especially water-limited.

What’s under-appreciated is that this is a story about efficiency. When two thirds of the fuel we burn in power plants is wasted as heat, and that heat is rejected in cooling towers (at least in coal and nuke facilities), any gain in energy efficiency is a reduction in water use. Given the huge gains available in efficiency, it ought to be central to this discussion. Also bear in mind that Clean Air Act compliance and carbon sequestration drive down the efficiency of coal plants, thereby increasing water use per MWh.

Excerpts of the full article below the fold:

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U.S. power generators girding for possible mandatory curbs on greenhouse gas emissions may also find themselves facing another climate-related crisis: water shortages.

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This past summer — unusually hot and dry in many regions — offered a preview.

As electricity demand surged to keep air conditioners whirring, power plants confronted shortages of cooling water that forced shutdowns and led to inefficient operations. And that problem is expected to worsen as climate change intensifies summer heat waves and droughts in already-arid areas.

Water is no longer an afterthought for power plant planners, said Bob Goldstein, the Electric Power Research Institute’s senior technical executive for water and ecological systems. That wasn’t the case so long ago when proximity to transmission lines and fuel dominated power companies’ planning.

“After you chose what type of plant you were going to build and site it, then you went about getting the water,” Goldstein said. “Now, you have to consider the water up front as you decide where you are going to build it.”

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Electric generators are facing growing competition for water from thirsty cities, sprawling farms and new environmental regulations aimed at protecting aquatic resources and recreational activities. “Power plants are the last group in the queue,” said Tom Feeley, technology manager for the National Energy Technology Laboratory’s (NETL) Innovations for Existing Plants Program.

If current trends continue, power plants will be withdrawing 7.3 billion gallons a day by 2030 — equal to all U.S. water consumption a decade ago, according to a Department of Energy report.

Ironically, nuclear power plants — touted by the nuclear industry and its supporters as the answer to global climate woes because reactors don’t emit greenhouse gases — need more freshwater to keep from overheating than other generators.