Policies on the Electrical Grid Affect the Severity and Location of Impacts of Charging Electric Vehicles

EVs are a substantial element of policy strategies to address climate change and air pollution, including the Transportation and Climate Initiative (TCI), a proposed policy to create a cap-and-invest program to reduce carbon dioxide emissions in the Northeastern U.S. Here, we evaluate a policy proposed under TCI, while including the effect of the additional grid load from charging EVs. We then evaluate this effect in a "business as usual" (BAU) grid scenario and a scenario where Pennsylvania joins the Regional Greenhouse Gas Initiative (RGGI). To evaluate this, we used estimates of increased electricity demand from the National Energy Modeling System (NEMS) and linked that with the Integrated Planning Model (IPM) to determine the grid response to the increased electrical load under each scenario. We modeled the changes in emissions and air quality using the Sparse Matrix Operator Kernel Emissions (SMOKE) modeling system, linked to the Community Multiscale Air Quality (CMAQ) model. Changes in air quality were then fed into the Environmental Benefits Mapping and Analysis Program in R (BenMAPR), an air pollution health impact assessment (HIA) platform based on BenMAP from the U.S. EPA, but adding the health impacts of NO2 alongside that of fine particulate matter (PM2.5) and ozone, along with asthma and birth outcomes.

We found that the magnitude and the geographic location of health benefits and impacts depended on grid conditions. Our BAU scenario resulted in 550 (95% CI: 340-780) deaths avoided per year, along with other health benefits. However, in a scenario where PA joins RGGI, we observe a reduction in health benefits (370 deaths avoided per year, 95% CI: 200-580), related to increased electricity generation from coal-fired power plants outside of PA. In both cases, over half of the avoided mortality and over 80% of the avoided asthma exacerbations are from reduced NO2 exposure, which is not included in most HIAs.

Our results show the value of spatially explicit evaluations of health impacts, since they can reveal spatial dynamics not apparent in aggregate totals. They also show the importance of incorporating changes in emissions from the electrical grid when evaluating the benefits or impacts of electrification. Additionally, our results demonstrate the importance of including NO2 in air pollution HIAs.