Surface area of solar arrays in the conterminous United States

The U.S. Geological Survey (USGS) Fort Collins Science Center created a national data set of the footprint area of solar arrays for the Bureau of Land Managements National Operations Center. We identified potential solar facility locations for the conterminous U.S. using the U.S. Energy Information Administration (EIA) utility-scale facilities data from 2015. The footprint area of each solar array was digitized on-screen using true color aerial imagery from the most recently available National Agriculture Imagery Program (NAIP) for each state (NAIP 2013-2015). We used supplementary ESRI basemap imagery accessed via ArcGIS to verify locations of arrays observed in NAIP imagery. Arrays separated by more than 30 meters were delineated as separate polygons. Access roads and other adjacent infrastructure were not included in the array footprint. Attribution for each array was derived from the EIA data and augmented with the date of aerial imagery used for delineation, the area of each array, and ground surface characteristics (artificial impervious or non-impervious). As of 2015, solar arrays covered a total of 191.57 square kilometers, only 2.8 percent of which was located on impervious surfaces. There were 176 utility-scale solar facilities (319 arrays) on impervious surfaces and 564 facilities (888 arrays) on non-impervious surfaces.