More than 86% of electricity in the U.S. is produced in thermoelectric power generating plants, most of which use coal, natural gas, or nuclear power to generate thermal energy. The thermal energy drives steam turbines to produce electrical power, and typically more than 60% of the original energy is wasted and carried away as low-grade heat. Operators must remove this heat, and 99% of baseload thermoelectric plants in the U.S. use water-cooled systems, or wet cooling, to do so. Power plant operators prefer wet cooling over dry-cooling systems because ambient water temperatures tend to be cooler and more stable than air temperatures and because water evaporation allows for additional cooling capacity, enabling more cost-effective rejection of heat. As a result, wet-cooling systems at power plants currently account for 41% of all fresh water withdrawals in the U.S. Availability of fresh water resources is increasingly strained by drought and growing demand, and potential climate change impacts add uncertainty to the quality and quantity of future water supplies. Unfortunately, current dry-cooling technologies drive down the efficiency of power generation compared with the efficiency of wet cooled generators. By advancing innovations to address this challenge, ARID projects could protect the efficiency of U.S. electric power generation, accelerating the adoption of dry cooling and reducing the dependence on water for thermoelectric power generation. Moreover, economical dry-cooling technologies could provide more flexibility in siting facilities, since a nearby source of water, such as a river, would not be necessary.

If successful, innovations developed under the ARID program could enhance the efficiency and cost-competitiveness of dry-cooling systems for thermoelectric power generation and reduce dependence on water for cooling power plants.