GAO Report Emphasizes Smarter Use of Water in Power Plants
On October 16, the Government Accountability Office (GAO) released a report entitled Energy-Water Nexus: Improvements to Federal Water Use Data Would Increase Understanding of Trends in Power Plant Water Use. The report recommends three measures to raise awareness of and reduce freshwater usage in power plants. First, energy producers should implement technological innovations and other measures to reduce freshwater use in power plants. Second, states should take the water impact of power plants into consideration when regulating and approving new construction. Third, the report recommends new federal data standards to increase the accuracy of water use data and its usefulness to state regulators. Currently, the United States Geological Survey (USGS) measures freshwater withdrawals for power plants, but not the net amount of water consumed and not returned to the source.
Several technologies could play a role in mitigating freshwater use in power plants. Thermoelectric power plants, which account for nearly 80 percent of electricity generation in the United States, produce electricity by heating water with coal, natural gas, nuclear, biomass, and other fuels. The resultant steam runs turbines to generate electricity. Freshwater is used again to condense steam for reuse. Advanced cooling technologies such as hybrid cooling systems "are typically designed to use 20-80 percent of the water used for a wet recirculating system with cooling towers.” Another option would be to use alternative water sources such as groundwater unsuitable for drinking, seawater, and industrial wastewater. Advanced cooling and alternative water source technologies already have limited commercial use and are under further development.
Water and electricity production are closely interlocked, as power plants in the United States use 39 percent of total freshwater withdrawals. The water demands of power plants must be balanced with those of the residential, industrial, and agricultural sectors, particularly in water-stressed areas. Reducing the freshwater footprint of electric generation allows for greater flexibility in siting power plants and strengthens the security of our energy supply in areas that will experience more severe and frequent droughts due to climate change.