An Assessment of Water Demand and Availability to meet Construction and Operational Needs for Large Utility-Scale Solar Projects in the Southwestern United States

In the Southwestern United States, there are many large utility-scale solar photovoltaic (PV) and concentrating solar power (CSP) facilities currently in operation, with even more under construction and planned for future development. These are locations with high solar insolation and access to large metropolitan areas and existing grid infrastructure. The Bureau of Land Management, under a reasonably foreseeable development scenario, projects a total of almost 32 GW of installed utility-scale solar project capacity in the Southwest by 2030. To determine the potential impacts to water resources and the potential limitations water resources may have on development, we utilized methods outlined by the Bureau of Land Management (BLM) to determine potential water use in designated solar energy zones (SEZs) for construction and operations & maintenance (O&M), which is then evaluated according to water availability in six Southwestern states. Our results indicate that PV facilities overall use less water, however water for construction is high compared to lifetime operational water needs. There is a transition underway from wet cooled to dry cooled CSP facilities and larger PV facilities due to water use concerns, though some water is still necessary for construction, operations, and maintenance. Overall, ten watersheds, 9 in California, and one in New Mexico were identified as being of particular concern because of limited water availability. Understanding the location of potentially available water sources can help the solar industry determine locations that minimize impacts to existing water resources, and help understand potential costs when utilizing non-potable water sources or purchasing existing appropriated water. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.