Quantifying land-energy interactions of hydropower in the Western United States

Estimates for the land use of electricity generation technologies rely on limited information, challenging the representativeness of assumptions in energy systems analyses that use tools like life cycle assessment and grid optimization. This study used facility-level geospatial image analysis to quantify the land directly impacted for over 500 hydroelectric power plants in the U.S. Western Interconnection to create a database of the land requirements of hydropower projects, classifying power plants by mode of operation. The area of the plant, reservoir, and conveyance channels was delineated using aerial imagery to determine land-use efficiency (W/m2) and land transformation (m2/MWh). Run-of-river facilities without reservoirs have higher land-use efficiencies than storage facilities with reservoirs, with a median operational land-use efficiency of 150 W/m2 (range 1.3–13,000 W/m2) compared to storage projects with a median of 1.4 W/m2 (0.010 W/m2 – 98 W/m2). Run-of-river projects’ median annual land transformation is 0.78 m2/MWh (0.0090–88 m2/MWh), two orders of magnitude lower than the median for storage projects, 84 m2/MWh (1.2–11,000 m2/MWh). Reservoirs are documented for 45 % of the run-of-river plants, resulting in median annual land transformation of 15 m2/MWh (0.028–6700 m2/MWh), one fifth of the median for storage projects. Results confirm the importance of using land sparing opportunities for new projects, such as upgrading hydropower plants and converting non-power dams to reduce or eliminate additional land requirements. The resulting inventory has broad applicability in future research focused on life cycle assessment, energy transitions, power systems planning, and the evaluation of ecological impacts of hydropower.