THE ENERGY-WATER CONNECTION

Energy Production Pushing Water Supply to Choke Point
Lisa Song, September 28, 2010 (SolveClimate via Reuters)

"After agriculture, the energy sector is the largest consumer of water in the US. Freshwater resources are already dwindling due to climate change and current population levels, and that burden is likely to intensify. The Energy Information Administration estimates a 40% increase in energy demand by 2050, when the U.S. population is expected to hit 439 million.

"But…[many] alternative energies—whether renewables like solar thermal and biofuels, or unconventional sources like oil tar sands—use more water than conventional fossil fuels…The report, Choke Point: U.S. argues there can be no energy security without water, and both must be managed together if the country is to avoid shortages of either resource…[The study’s] findings aren’t entirely unexpected. They parallel a pair of reports commissioned by Congress in 2004…[A 2007 report] by Sandia National Labs…laid out the conflicts between energy demand and water availability… Energy-Water Research and Development Roadmap is intended to detail solutions and research directions…[I]ts general contents were summarized in a separate March 2007 Sandia National Labs paper."

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"In 2000, the energy sector withdrew nearly 200 billion gallons of freshwater and seawater per day. That's about half of the country's daily water withdrawals…[Most] is used for cooling thermoelectric plants, whether powered by oil and gas, nuclear fuels, biomass or concentrated solar. Only wind and photovoltaic solar plants use virtually no water at all…[And] water resources are dwindling…[P]lans to dismantle older dams will decrease surface water storage…[and] climate change has led to droughts, decreased runoff and lower river levels…States like California rely on faraway water sources, so much of the state's energy is used for the transport of water from reservoir to cities. As the reservoirs dip lower from drought, it will take even more energy to operate the water pumps…Solar plants in California have been stalled or scaled back due to water availability…Europe is feeling these pressures too…

"Options do exist…Power plants can use brackish water or wastewater for cooling. Another possibility is to switch to dry cooling, where air, rather than water, is used to cool the plant…Interest in energy security is pushing the development of domestic alternatives such as oil shales, which are more water-intensive than conventional crude oil…[I]t takes about 1.5 gallons of water to produce one gallon of petroleum; oil shale production requires 2 to 3 gallons of water. Moreover, most oil shale deposits are in Wyoming, Colorado and Utah, three states with existing water problems."

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"Ironically, water and sustainability measures can often clash…Biofuels produced from irrigated corn use 650 times more water than oil-derived gasoline…[S]oybean-based biofuels…[use] around 1,000…[F]ossil fuel plants that attempt to bury their CO2 will consume 40%–90% more water…"

[From a draft of the Sandia paper:] "It may not be possible in many areas of the country to meet the country's growing energy and water needs by following the current U.S. path of largely managing water and energy separately while making small improvements in freshwater supply and small changes in energy and water-use efficiency."