Transitioning to zero freshwater withdrawal in the U.S. for thermoelectric generation

Drought poses important risks to thermoelectric power production in the United States because of the significant water use in this sector. Here a scoping level analysis is performed to identify the technical tradeoffs and initial cost estimates for retrofitting existing thermoelectric generation to achieve zero freshwater withdrawal and thus reduce drought related vulnerabilities. Specifically, conversion of existing plants to dry cooling or a wet cooling system utilizing non-potable water is considered. The least cost alternative is determined for each of the 1178 freshwater using power plants in the United States. The projected increase in levelized cost of electricity ranges roughly from $0.20 to $20/MW h with a median value of $3.53/MW h. With a wholesale price of electricity running about $35/MW h, many retrofits could be accomplished at levels that would add less than 10% to current power plant generation expenses. Such retrofits would alleviate power plant vulnerabilities to thermal discharge limits in times of drought (particularly in the East) and would save 3.2 Mm3/d of freshwater consumption in watersheds with limited water availability (principally in the West). The estimated impact of retrofits on wastewater and brackish water supply is minimal requiring only a fraction of the available resource. Total parasitic energy requirements to achieve zero freshwater withdrawal are estimated at 140 million MW h or roughly 4.5% of the total production from the retrofitted plants.