Carbon Balance with Renewable Energy: Effects of Solar Installations on Desert Soil Carbon Cycle
December 03, 2020
Energy Research and Development (500)
Electric Program Investment Charge - EPIC
Jennifer Mills, Laura Lammers, and Ronald Amundson
This research examined the response of California desert soil carbon to 21st-century climate change, and the effect of large-scale solar installations on desert soil carbon balances. Three sites in the Mojave National Preserve were instrumented and monitored intensely for two years. A heat, water, and geochemical model was developed to mimic current conditions, and extrapolate conditions into the future as California’s climate changes. The Mojave Desert is one of the most rapidly warming areas in the United States, and empirical evidence of potential declines in soil carbon storage due to warming have been discovered. The current expansion of large-scale solar in the western Mojave Desert is on abandoned agricultural land. A year of intensive micrometeorological measurements at a utility-scale solar installation shows that panels produce complex changes in the heat and water balance of the site. Since vegetation is kept to a minimum under most solar installations, there is expected to be a slow loss of remaining soil organic carbon due to a lack of inputs. Due to this slow loss of remaining soil organic carbon, large-scale solar installations, especially those on already impacted agricultural lands, are not expected to contribute in any significant way to the soil carbon loss. Inorganic carbon stocks, based on geochemical modeling, are predicted to remain and increase, though at a slightly slower rate than the control site.