Analyzing land and water requirements for solar deployment in the Southwestern United States

Among the types of renewable energy, solar energy is rapidly gaining popularity. Advances in technology have contributed to improved efficiency and reduced costs for solar energy systems, which can be placed in two categories: concentrated solar power (CSP) and solar photovoltaics (PV). Both types have to use water to clean the mirrors/panels to maintain their efficiency. CSP technology has additional water requirements for wet-cooling, dry-cooling, and hybrid cooling methods. For utility-scale solar deployment, water is also required during solar plant construction and dismantling. The southwest U.S. possesses abundant solar potential, but the expansion of solar power may be restricted by the limited availability of water. Estimates were gathered for water and land use for solar systems and harmonized through review and screening of relevant literature. Next, the estimates were incorporated into a system dynamics model to analyze water availability and usage, land availability and usage, and associated reductions in carbon emissions for utility-scale solar development in the solar energy zones (SEZ) of six southwestern states based upon the renewable portfolio standards (RPS) during 2015-2030. Results showed that solar PV was the most appropriate technology for water-limited regions. Sufficient land was available within the 19 SEZs to meet the RPS requirements. Available water was adequate to meet RPS solar carve-out water requirements for Nevada and New Mexico. For future work, the generated model can be modified to analyze the performances of renewables in addition to solar.