This web page provides an overview of USGS's research about thermoelectric power. It includes related research and a collection of data and tools. Water for thermoelectric power is used in the process of generating electricity with steam-driven turbine generators. Since 2000, thermoelectric-power withdrawals have been compiled by cooling-system type. Once-through cooling refers to cooling systems in which water is circulated through heat exchangers, and then returned to the source. Recirculating cooling refers to cooling systems in which water is circulated through heat exchangers, cooled using ponds or towers, and then recirculated. Subsequent water withdrawals for a recirculating system are used to replace water lost to evaporation, blowdown, drift, and leakage. Thermoelectric power cooling water sources include fresh and saline water from both surface-water and groundwater sources (Introduction).