GC013-06
Air Quality and Climate Impacts of United States Nuclear Power Plant Closures
Monday, 7 December 2020: 07:15
Virtual
Lyssa Freese, Massachusetts Institute of Technology, Earth, Atmosphere and Planetary Sciences, Cambridge, MA, United States, Guillaume Chossiere, Massachusetts Institute of Technology, Cambridge, MA, United States, Sebastian David Eastham, Massachusetts Institute of Technology, Laboratory for Aviation and the Environment, Cambridge, MA, United States and Noelle E Selin, MIT, Cambridge, MA, United States
Abstract:
The United States’ future energy mix is likely to include a partial or complete drawdown from its current 20% reliance on nuclear power. This is due to policy changes and to scheduled shutdowns of nuclear power plants that have reached the end of their lifetime. Given projected growth in demand, the base-load nature of nuclear power, and the intermittency of most renewable resources, fossil fuel-based energy will make up at least part of this deficit. This in turn will impact air quality, greenhouse gas emissions, and human health. We develop and evaluate a generator-level energy grid optimization and emissions model, and couple it with the chemical transport model, GEOS-Chem, to estimate the impact that an immediate shutdown of nuclear power plants would have on concentrations of ozone and fine particulate matter (PM
2.5) across the United States. We evaluate climate co-disbenefits by also quantifying changes in CO
2 emissions, and what they mean for reaching larger climate goals. Importantly, our generator-level energy grid model allows us to assess variations across the scenarios at a local scale, which occur due to a combination of local fuel sources, demand patterns, and chemical regimes.
When compared to a no-shutdown scenario, loss of nuclear generation leads to a nationwide increase of 42%, 44%, and 40% in NOx, SO2, and CO2 emissions, respectively, from both coal and natural gas. Nationwide, concentrations of PM2.5 increase, particularly in regions where shutdowns occur in the presence of coal plants, while summertime ozone decreases throughout the Northeast and Midwest. CO2 emissions from the electricity sector increase from 1.8 to 2.5 billion tons, corresponding to a 14% increase in total CO2 emissions from the United States. This suggests that rapidly shutting down nuclear power plants shifts the current generation mix towards dirtier fuel sources, degrading air quality and increasing CO2 emissions nationwide.
Realistically, shutdowns will occur over longer timescales during which new generation will be deployed; this work emphasizes the need to prioritize renewables coupled with improved storage and transmission for this deployment. If clean energy is not put in place to replace declining nuclear capacity, the outcomes of even a slow nuclear shutdown are likely to include some or all of the impacts we calculate.
