<< Previous

Defining Water Withdrawal, Consumption
All power plants that generate electricity by producing steam to move a turbine rely on water for cooling. These plants—fueled by coal, natural gas and nuclear energy—produce about 90 percent of all the electricity that powers America’s homes and economy. This electricity also powers water purification systems, pumping stations and waste-water treatment plants that residents, businesses and communities rely upon in society. In this way, electricity and water are interdependent.

The amount of water actually consumed by electric power generation is very small compared to other economic sectors. Thermoelectric power plants withdraw large volumes of water, but, depending on the design, most of the water is returned to its source.

A critical distinction is the difference between water withdrawn from a lake or river by a power plant and water actually consumed by the plant.

Plants that have an open-cycle cooling system withdraw water to cool steam and equipment through a system of pipes that circulates the water through components. After the water is withdrawn, virtually all of it is quickly returned to its source. This water never encounters the reactor or radioactive material.

For plants that have a closed-cycle cooling system using a cooling tower or cooling pond, water is withdrawn to cool steam and equipment through evaporation. Most of this water is not returned to its source.

Because rainfall in some areas of the country in 2007 was 15 to 20 inches below normal, energy companies have taken steps to reduce water consumption and otherwise conserve water supply.

Energy companies have worked with state and local governments and public water system operators to manage water use during drought conditions. In the Southeast, this coordinated approach to conservation resulted in more than a 20 percent water savings in 2007.