Some thermoelectric power plants employ “once-through” systems that draw water for cooling purposes and then treat and discharge the water. These require more withdrawals, but result in less total consumption. The opposite is often true for power plants that utilize ponds or cooling towers to reuse water through “closed-loop” systems. These require relatively less water in terms of withdrawals, but can ultimately consume more water through evaporation in the cooling process. Some newer plants (mostly natural gas-fired) use hybrid or dry cooling systems that consume little to no water. These systems, however, typically require additional energy to operate.

Nuclear power plants withdraw and consume the largest amounts of water, followed by power plants that use fossil fuels (coal or oil), biomass, or waste. Natural gas-fired power plants tend to use the least amount of water.

Note: This graphic is not specific to the U.S. Southeast.