Water Use
US-REGEN also estimates water use from the energy system based on the mix of deployed technologies and assumptions about water consumption and withdrawal rates for both existing activities and new technologies for electric generation and fuel supply and conversion. Water withdrawal refers to the amount of water diverted a water source for use at a plant or other facility; water consumption (or consumptive use) refers to the portion of water withdrawals that is not returned to the source, either due to evaporation, incorporation into a product, or other removal. Most water withdrawals in the energy system are for once-through power plant cooling, which account for around 40% of economy-wide water withdrawals. However, only 3% of power plant cooling withdrawals result in consumptive use. For existing electric generators, water withdrawal and consumption coefficients are derived from plant-level EIA reporting, distinguishing by unit type and cooling technology. For new technologies, the model applies assumed water coefficients based on a technical assessment of cooling and conversion processes (for example, see Figure 1). For more details, see this EPRI report.
