A new dataset released by the Energy Information Administration (EIA) — which combines water withdrawal, electricity generation, and plant configuration data into a single database — enables detailed examination of cooling system operation at thermoelectric plants at multiple scales, most importantly at the unit level. This dataset was used to explore operations across the population of U.S. thermoelectric plants, leading to the conclusion that roughly 32% of all thermoelectric water withdrawal occurs while power plants are not generating electricity. Based on interviews with industry representatives, a unit’s location on the dispatch curve will largely dictate how the cooling system is operated. Peaking plants and intermediate plants might keep their cooling system running to maintain dispatchability. Other considerations include minimizing wear and tear on the pumps and controlling water chemistry.
This observation has implications for understanding water use at thermoelectric plants, policy analysis, and modeling. Previous studies have estimated water use as a function of cooling technology, fuel type, prime mover, pollution controls, and ambient climate (1) or by calculating the amount of water that is thermodynamically necessary for cooling (2). This, however, does not capture all the water a plant is withdrawing simply to maintain dispatchability. This paper uses the new data set from EIA and interviews with plant operators to illuminate the role cooling systems operations play in determining the amount of water a plant withdraws.