The U.S. electric sector's reliance on water makes it vulnerable to the impacts of climate change on water resources. Here we analyze how constraints on U.S. energy system carbon dioxide (CO2) emissions could affect water withdrawal and consumption in the U.S. electric sector through 2055. We use simulations of the EPA's U.S. 9-region (EPAUS9r) MARKAL least-cost optimization energy systems model with updated water use factors for electricity generating technologies. Model results suggest CO2 constraints could force the retirement of old power plants and drive increased use of low water-use renewable and nuclear power as well as natural gas CCS plants with more advanced cooling systems. These changes in electric sector technology mix reduce water withdrawal in all scenarios but increase water consumption in aggressive scenarios. Decreased electric sector water withdrawal would likely reduce electric sector vulnerability to climate change, but the rise in consumption could increase competition with other users.Master of Scienc
