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Water Discharge

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Various Energy Resources

Water Discharge

Some forms of electricity generation involve the discharge of water. These water discharges can contain pollutants. In addition, drilling and mining operations can affect water quality. These environmental impacts are regulated by a variety of federal, state and local laws. The water quality impacts of electricity generation vary from technology to technology, as described below.

Natural Gas

Combustion turbines do not produce any water discharges. However, pollutants and heat build up in the water used in natural gas boilers and combined cycle systems. When these pollutants and heat reach certain levels, the water is often discharged into lakes or rivers. This discharge usually requires a permit and is monitored. For more information about these regulations, visit EPA's Office of Water Web site.

Coal

Pollutants build up in the water used in the power plant boiler and cooling system. If the water used in the power plant is discharged to a lake or river, the pollutants in the water can harm fish and plants. Further, if rain falls on coal stored in piles outside the power plant, the water that runs off these piles can flush heavy metals from the coal, such as arsenic and lead, into nearby bodies of water. Coal mining can also contaminate bodies of water with heavy metals when the water used to clean the coal is discharged back into the environment. This discharge usually requires a permit and is monitored. For more information about these regulations, visit EPA's Office of Water Web site.

Oil

Refineries release treated wastewater, which can contain pollutants, into streams and other bodies of water. Likewise, power plants release wastewater, which contains pollutants and is generally hotter than the water in nearby lakes and streams, often harming fish and plants. This discharge usually requires a permit and is monitored. For more information about these regulations, visit EPA's Office of Water Web site.

Drilling can also cause underground water supplies to become contaminated with oil, and runoff from the extraction process can affect surface waters. During the transportation of oil, spills can occur, damaging water quality and harming marine life and birds in oceans and coastal waterways.

Nuclear Energy

Water pollutants, such as heavy metals and salts, build up in the water used in the nuclear power plant systems. These water pollutants, as well as the higher temperature of the water discharged from the power plant, can negatively affect water quality and aquatic life.

Although the nuclear reactor is radioactive, the water discharged from the power plant is not considered radioactive because it never comes in contact with radioactive materials.1 However, waste generated from uranium mining operations and rainwater runoff can contaminate groundwater and surface water resources with heavy metals and traces of radioactive uranium.

Municipal Solid Waste

Similar to fossil fuel power plants, MSW power plants discharge used water. Pollutants build up in the water used in the power plant boiler and cooling system. In addition, the cooling water is considerably warmer when it is discharged than when it was taken. These water pollutants and the higher temperature of the discharged water can upon its release negatively affect water quality and aquatic life. This discharge usually requires a permit and is monitored. For more information about these regulations, visit EPA's Office of Water Web site.

Hydroelectricity

Hydroelectric power plants release water back into rivers after it passes through turbines. This water is not polluted by the process of creating electricity.

Non-Hydroelectric Renewable Energy

Solar

Solar technologies do not discharge any water while creating electricity.

Geothermal

Geothermal power plants can possibly cause groundwater contamination when drilling wells and extracting hot water or steam. However, this type of contamination can be prevented with proper management techniques. In addition, geothermal power plants often re-inject used water back into the ground (through separate wells) instead of discharging the used water into surface waters. This prevents underground minerals or pollutants from being introduced into surface waters.

Biomass

As is the case with fossil fuel power plants, biomass power plants have pollutant build-up in the water used in the boiler and cooling system. The water used for cooling is much warmer when it is returned to the lake or river than when it was removed. Pollutants in the water and the higher temperature of the water can harm fish and plants in the lake or river where the power plant water is discharged. This discharge usually requires a permit and is monitored. For more information about these regulations, visit EPA's Office of Water Web site. In general, crops grown for biomass fuel require fewer pesticides and fertilizers than crops grown for food, which means that less pesticide and fertilizer runoff will reach local streams and ponds than if food crops are grown.

Landfill Gas

Engines and combustion turbines burning landfill gas have very little or no water discharges. The collection of landfill gas involves drilling wells into landfills, which does not affect local bodies of water.

Wind

Wind turbines do not discharge any water while creating electricity.

  1. Nuclear Energy Institute, Fact Sheet: Nuclear Energy and the Environment (PDF) (3 pp., 57K, About PDF) Exit EPA Disclaimer. July 2000.

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