1166648 - COVID and Beyond: Impact of COVID-19 Intervention on 2020 Power Plants Emissions in the United States Using Generalized Synthetic Control Methods

COVID-19 public health interventions in the United States resulted in large-scale changes in population activity, potentially resulting in short and long-term changes in electric generating unit emissions. This study investigates the COVID-19 pandemic impact on U.S. power plant SO2, NOx and CO2 emissions under a causal inference framework. We use emissions data from 937 U.S. electricity generating units (EGUs) from EPA's Clean Air Markets Database from 2010-2020. We train the GSYNTH model on weekly power plants emissions data from 2010-2020 using meteorological and seasonal parameters as covariates to estimate hypothetical counterfactual emissions from each facility, i.e., expected business as usual (BAU) emissions assuming no pandemic in 2020. The model is evaluated against naive approaches such as long-term averaging of emissions. We try to identify the plants characteristics that play a role on actual and counterfactual emissions. Finally, we quantify ambient PM2.5 concentration changes attributable to EGU SO2 emissions (“coal PM2.5”) using a reduced complexity model, disperseR. We find in 2020 that out of 937 EGUs, 586 EGUs saw SO2 emissions increased relative to expected emissions under BAU and 559 EGUs saw NOx emissions increased relative to expected emissions under BAU and, with most of the increases occurring in the eastern parts of the U.S. Nationwide SO2 emissions increased 44% (4656 tons SO2/week) during March-December 2020 and 47% (3073 tons of SO2/week) during the lockdown period compared to BAU. NOx emission are 23% greater than BAU (2,277 tons NOx/week) from March to December 2020 and 19% greater (318 tons NOx/week) during the the lockdown period (March-April, 2020). CO2 emissions are around 14% (2.3 million tons/week) higher than BAU in longterm period and around 7.5% (877,000 tons/week) higher during lockdown period. We find facilities using coal as primary fuels mostly in the eastern region of the U.S. are main driver for the increased SO2, NOx and CO2 emissions. An average increase over BAU of 13% (16%) coal PM2.5 concentration was observed from coal facilities during the lockdown period (from March-December, 2020). We find large emissions increases across many facilities, especially coal/natural gas/other facilities located in the country's eastern region. The increases weren't ubiquitous, however, as many facilities did reduce their emissions. The results highlight that any sustained influence of population activity shifts—e.g., greater percentages of the work force working from home—did not lead to reduced power plant emissions in the U.S. in 2020.