Harry Stevens is a freelance reporter covering climate change, corporate social responsibility, social enterprise, and sustainable finance. Harry has contributed to several media outlets, including Justmeans, GreenBiz, SocialEarth, and Sustainablog. You can follow Harry on Twitter: @Harry_Stevens...
Report Reveals Unsustainable Water Requirements for U.S. Energy Policy
A new report reveals that traditional electricity generation technologies require huge demands on increasingly scarce water resources, while solar and wind power plants require relatively little water.
The report, "The Hidden Costs of Electricity: Comparing the Hidden Costs of Power Generation Fuels," analyzes the indirect and externalized costs of six fuels used to generate electricity: biomass, coal, nuclear, natural gas, solar (photovoltaic and concentrating solar power), and wind (both onshore and offshore). The report finds that of these technologies, only solar and wind power promise to produce power without relying on unsustainable amounts of water.
Nuclear power plants have critical cooling requirements that necessitate huge amounts of water. Almost 40 percent of U.S. nuclear plants use open-loop cooling systems, which need between 25,000 and 60,000 gallons per megawatt hour (MWh). Nuclear reactors with closed-loop cooling systems withdraw between 700-1,100 gallons of water per megawatt hour (MWh), most of which is lost to evaporation.
Coal plants also have open- and closed-loop cooling systems. Open-loop systems require between 20,000 and 50,000 gallons of water per MWh, while closed-loop systems withdraw between 500 and 600 gallons per MWh. Coal power plants have also been known to pollute streams and drinking water through mining and coal-ash dump sites.
Shale fracking for natural gas, a hot-button issue of late, can use anywhere from two to 10 million gallons of water per well. This water is usually taken from on-site surface or groundwater supplies, producing a tremendous strain in areas with stressed water supplies, areas undergoing drought conditions, or locations with sensitive aquatic communities.
Biomass generation, which produces fuel like ethanol, requires enormous quantities of water. Crops that have been dedicated to energy production require between 40,000 and 100,000 gallons of water per MWh, although some crops exceed this range.
Wind and solar power, the two most promising sources of renewable energy, require negligible amounts of water by comparison. The most water-intensive solar plants are called concentrated solar plants (CSPs) and consume around 800 gallons per MWh for cooling. Some CSP plants use dry cooling and need only 80 gallons per MWh. Photovoltaic plants (PVs) use a negligible amount of water, but PVs cannot store energy like CSPs. Wind plants use a negligible amount of water in the generation process.
The report, prepared by Synapse Energy Economics, Inc., a research firm that specializes in the electricity and natural gas industry, adds weight to the argument that a switch to renewable energy has become urgent as the effects of climate change accelerate.
Water scarcity, too, has become increasingly alarming. Lake Mead in Arizona, which supplies water to 22 million people, could be dry by 2021. Americans in the Southwest that rely on the Colorado River for drinking and irrigation face serious threats to their future water supply. The Ogallala Aquifer, the vast underground reservoir beneath the Great Plains, is steadily being depleted.
"The government and energy industries are literally flying blind as they plan for continued reliance on coal, natural gas, nuclear power and industrial biomass to meet our energy needs," said Grant Smith, senior energy analyst at the Civil Society Institute (CSI), a Massachusetts-based think tank. "Each of these is water intensive and leads to pollution of water, which is increasingly scarce and in competition for other uses such as agriculture and other commercial uses. The drought intensifies the urgency and the imperative that political leaders in both parties hit the pause button on the headlong rush to support nuclear power and fossil fuel use."
The Republican-led House of Representatives, which has amassed "the worst environmental record of any Congress in history," according to a House Committee on Energy and Commerce minority report, is openly hostile to efforts to protect the environment.
The House is currently considering the "Stop the War on Coal Act" (H.R. 3409), introduced by Representative Bill Johnson (R-OH), which would prevent the EPA from using the Clean Air Act to impose greenhouse gas regulations on the coal industry, and from using the Clean Water Act to protect water resources.
"In 2005 the Congress mandated a federal water/energy roadmap," said Seth Sheldon, lead water/energy analyst at CSI. "Nearly eight years later, that roadmap has not been produced and either through bureaucratic inertia or fear of hard political questions, the questions are not even being asked, much less their solutions explored. At a time of significant water scarcity and increasing threats to water quality, we can ill afford to ignore this central question about the future of our energy choices."
Image credit: Michael Betke