How Much Water Can We Save by Achieving Renewable Portfolio Standards in the Southwest United States?

Electricity in the Southwestern United States is primarily generated with water intensive steam turbines. If energy demand continues to rise this will lead to a further rise in water demand. A comprehensive understanding of water consumption and withdrawal for utility scale generation of electricity is necessary before any improvements in the water efficiency of such systems in arid environments can be made. This study estimated and compared the water usage associated with thermoelectric generation (i.e., natural gas, coal), and solar energy, in the five driest Colorado River Basin states: Utah, New Mexico, Nevada, Arizona, and California. This study also examined and compared each state’s Renewable Portfolio Standards (RPS) and how this might impact water savings. Results showed that each state’s current RPS goals would reduce the water that is consumed by the generation of electricity. However, the amount of water savings will vary on a state by state basis. In order to reduce water consumption, replacing thermal electric generation with photovoltaic (PV) solar can be significant and should be encouraged. The amount of water saved will vary, however, depending on the state’s choice of coal or natural gas.