Friday, February 16, 2007

Interdependency Of Energy & Water - The Energy-Water Nexus

Feb 15: The U.S. Department of Energy, Sandia National Laboratories has recently posted a December 2006 report entitled, Energy Demands on Water Resources: Report to Congress on the Interdependency of Energy and Water. The report was prepared in response to a letter from the chairmen and ranking members of the House and Senate Subcommittees on Energy and Water Development Appropriations, dated December 9, 2004. The report was approved by DOE on January 12, 2007, and was sent to Congress on January 17, 2007. The DOE Office of Environmental Management approved public release of the Report on February 8, 2007. The report presents background information on the connections between energy and water, identifies concerns regarding water demands of energy production, and discusses science and technologies to address water use and management in the context of energy production and use.

Water is an integral element of energy resource development and utilization. It is used in energy-resource extraction, refining and processing, and transportation. Water is also an integral part of electric-power generation. It is used directly in hydroelectric
generation and is also used extensively for cooling and emissions scrubbing in thermoelectric generation.

The report points out that as the U.S. seeks to replace imported petroleum and natural gas with fuels from domestic sources, such as biofuels, synfuel from coal, hydrogen, and possibly oil shale, the demand for water to produce energy fuels could grow significantly.

Freshwater resources and overall freshwater availability become strained from limitations on supply and increasing domestic, agricultural, and environmental demands. Few new reservoirs have been built since 1980, and fresh surface-water withdrawals have leveled off at about 260 billion gallons per day. Many regions depend on groundwater to meet increasing water demands, but declining groundwater tables could severely limit future water availability. Some regions have seen groundwater levels drop as much as 300 to 900 feet over the past 50 years because of the pumping of water from aquifers faster than the natural rate of recharge.

If new power plants continue to be built with evaporative cooling, consumption of water for electrical energy production could more than double by 2030 from 3.3 billion gallons per day in 1995 to 7.3 billion gallons per day. Consumption by the electric sector alone could equal the entire country’s 1995 domestic water consumption. Consumption of water for extraction and production of transportation fuels from domestic sources also has the potential to grow substantially. Meanwhile, climate concerns and declines in groundwater levels suggest that less freshwater, not more, may be available in the future.

Access the complete 80-page report (
click here). Access the Sandia National Laboratories, Energy-Water Nexus website for additional information (click here). [*Energy, *Water]