Advancements in Solar Energy Life Cycle Assessment and Implications for Power Plants in the Western US

Abstract

New solar energy technologies, such as second-generation photovoltaic panels, are increasingly being installed at utility scale. Our accounting of the life cycle climate change impacts or carbon footprint of solar power technologies needs to be revised as technologies change and as prior omissions of related impacts are identified. This thesis aims to update the life cycle climate change impacts of two solar energy technologies. First, the direct land use change (DLUC) and albedo change impacts from removing native vegetation and installing CSP troughs were incorporated into life cycle assessment (LCA) scenarios for the four currently operational CSP trough power plants in the Southwest US. Through geospatial analysis, the original aboveground and belowground biomass carbon, organic soil carbon, and net primary productivity loss, and the before-and-after albedo difference of these sites were determined and converted to their contributions to the life cycle climate change impacts of CSP. The carbon-related impacts of the environmental change from desert soil to human infrastructure showed only a minor contribution (\u3c 5%) to the overall life cycle climate change impacts of electricity generated by CSP trough facilities. Albedo change impacts of three of the facilities, Mojave, Solana, and Genesis, show a similarly minimal contribution; however, the albedo change impacts of the Nevada Solar One CSP power plant result in a 11.27% increase in the total life cycle climate change impacts. In the second study, a cradle-to-grave LCA was performed for a 200 MW power plant comprised of cadmium telluride (CdTe) solar panels by Nevada Gold Mines, using primary data from the company. The study revealed a carbon footprint of 10.17 g CO2eq/kWh, a notable reduction from the LCA results of previous versions of CdTe panels. The carbon payback time of the facility was determined to be only 6 months in relation to the greenhouse gas emissions intensity of grid electricity. These new LCA results for CSP trough and CdTe panels can assist in building more accurate greenhouse gas inventories and in planning for an energy transition that minimizes greenhouse gas emissions