In the coming years, increasingly warm and dry conditions and longer droughts will affect water availability in many parts of the country.
Water-intensive coal plants are particularly vulnerable to energy-water collisions, which occur when insufficient water is available or water temperatures are too warm for power plant cooling.
Upgrading these plants to use cooling systems with lower water withdrawal needs would incur significant costs for many plants that are already economically uncompetitive, making them even stronger candidates for closure.
America's Costliest Coal Plants
- The UCS Report, Ripe for Retirement: The Case for Closing America's Costliest Coal Plants, identified 353 U.S. coal-fired generators that were no longer economically competitive and should be considered for closure.
- Since this analysis, power producers have announced the closure of 70 coal-fired generators, including 58 identified in the report as ripe-for-retirement, leaving 295 generators remaining on the ripe-for-retirement list.
- 175 of the remaining 295 ripe-for-retirement generators use once-through cooling systems, which involve large amounts of water withdrawals that place them at greater risk for energy-water collisions in the future.
Energy-Water Collisions Are Already Happening
Power plants use two major types of cooling systems: once-through and recirculating (see graphic).
Coal plants with once-through cooling are among the energy sources with the highest water withdrawals. Each of these plants withdraws 20,000 - 50,000 gallons for each megawatt-hour (MWh) of electricity. In contrast, a natural gas plant with once-through cooling withdraws only 7,500 - 20,000 gallons per MWh.
When water becomes scarce, or when water temperatures become too warm for cooling, power plants must reduce their electricity production -- often at times when electricity demand is highest.
These energy-water collisions are already happening and will get worse as temperatures increase and droughts become more frequent.
Retiring Water-Intensive Coal Plants Yields Big Water Savings
- Replacing aging water-hungry coal plants with technologies that require little or no water, like renewables and energy-efficient technologies that reduce overall electricity demand, would lead to significant water savings across the country and a cleaner, more resilient energy future.
- Approximately 8,421 billion gallons of water withdrawals and 149 billion gallons of water consumption could be avoided if both retiring and ripe-for-retirement generators were replaced with renewables and efficiency.
- States like Alabama, Maryland, Michigan, and Wisconsin could each save more than 250 billion gallons of water withdrawals a year by replacing uncompetitive coal generators with renewable energy. Similarly, Alabama, Florida, Georgia, and Mississippi could each save more than 5 billion gallons annually in water consumption.
Smart Policies Will Help Create a More Resilient Energy Future
- Utilities and investors should channel energy investments towards energy sources that do not emit harmful pollutants and do not put undue pressure on limited freshwater resources.
- Before approving costly retrofits, regulators should require utility companies to conduct system-wide planning to determine whether cleaner energy resources can more affordably meet customers’ electricity needs.
- Policies that encourage increased investments in renewable energy and energy efficiency can help reduce the health and environmental impacts of our nation’s power supply, and help shift the United States toward a cleaner, safer, and more reliable energy future.