Less than three percent of water withdrawn for thermoelectric power was consumed through evaporation. The heated water is then released back into the environment. That’s because most thermoelectric power plants in this country use what is known as once-through cooling, a process that pulls in cold river, lake or coastal water to cool the steam that turns a power plant’s turbines. Most of that was surface water used for cooling at power plants. In 2015, water withdrawals for thermoelectric power were estimated to be 133 Bgal/d or 41 percent of all withdrawals. Withdrawal and Consumption for Thermoelectric Power Generation Although domestic, at-home water use was a significant portion of that – 39 Bgal/d accounting for almost 12 percent of the total water withdrawn, thermoelectric power plants and agricultural irrigation consistently withdrew the largest portions, but they used that water in different ways. In 2015 (*the last year for which data is available), 322 Billion gallons per day (Bgal/d) of water – almost 488,000 Olympic-sized swimming pools – were withdrawn. Every five years, the United States Geological Survey makes an estimate of how much the country withdraws on a daily basis, and, for the first time since 1995, consumptive water use for thermoelectric power and irrigation were reported. The United States withdraws a lot of water every day for use in homes, businesses, industries and food production. In Handbook of Water Use and Conservation, by Amy Vickers, water withdrawal is defined as “water diverted or withdrawn from a surface water or groundwater source.” Consumptive water use, on the other hand, is defined as “water use that permanently withdraws water from its source water that is no longer available because it has evaporated, been transpired by plants, incorporated into products or crops, consumed by people or livestock, or otherwise removed from the immediate water environment.” It’s important to understand the difference between the two. “Water use” often fails to adequately describe what happens to water because “water use” can take two forms – consumption or withdrawal. While domestic use is significant, the majority of withdrawals are for thermoelectric power generation while crop irrigation has the highest consumption. The US withdraws a lot of water on a daily basis for use in homes, businesses, industries and food production. It’s important to understand the difference.
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