“Who breathes cleaner air when Americans put solar panels on their roofs? Using plant-level emissions data, an air-pollution transport model, and census-block demographics, Bobby Harris (Georgia Tech)—the study’s EPIcenter affiliate— and Travis E. Dauwalter (Artera Services) show that today’s rooftop solar fleet delivers $0.77 in environmental benefits per person annually and disproportionately benefits higher-income households.
Rooftop solar provides these benefits by displacing generation at coal and natural gas plants. By reducing power generation at fossil fuel plants, the emissions of harmful pollutants such as PM2.5, NOx, SO2, and CO2 —and the associated health costs of exposure to pollution— are reduced. The power plant at which generation is displaced varies by location, hour-of-day, and time-of-year based on varying electricity demand and supply conditions, so Harris and Dauwalter measure the emissions response of each power plant in the U.S. at every hour to solar generation in every zip code. This allows them to determine the total effect on emissions from installing a solar panel in a particular zip code.
Stopping at emissions is not enough, however. The damages to human health caused by those emissions depend on exposure—pollutants can be dispersed hundreds of miles away (e.g., remember when smoke from the 2024 western U.S. and Canada wildfires reached the East Coast?) and everyone living in the path of that dispersal can be affected. The intuition here is something long-recognized by environmental economists—pollution emitted in the middle of nowhere is much less harmful than the same amount of pollution emitted in a population center. To account for how power plant emissions are dispersed (fun fact: power plant smokestacks are designed to disperse pollutants—that’s why they are so tall!) and account for who is exposed to that pollution, the authors turn to a state-of-the-art air pollution transport model. This model tells them who is exposed to pollution from each power plant and how much. Using damage estimates from the environmental economics literature (essentially estimates of the mortality, morbidity, and productivity costs of exposure to each pollutant), the authors then translate these exposures into monetary damages. Putting all this together gives Harris and Dauwalter a measure of the
environmental benefits created by a rooftop solar system in each zip code and a measure of who receives those benefits (i.e., where those benefits occur).
Then, Harris and his co-author wondered: what if we moved panels to the places where a kilowatt does the most good? The authors show through a series of simulations that by moving solar arrays to areas with the goal of maximizing total benefits, the environmental benefits would increase nine-fold to $6.65 per resident and shift in favor of lower income households and households of color. Put another way, overall total benefits for the country would increase from $600 million dollars to $2.6 billion dollars if today’s solar arrays were sited to maximize the reduction of CO2 and other fossil fuel pollutants. One important finding is that siting rooftop solar for maximized benefits (regardless of race or income) simultaneously maximized benefits for people of color and for the lowest income households.
This paper showed that “capacity allocations that maximize total environmental benefits also nearly maximize distributional objectives, and current policies are shown to maximize neither efficiency nor equity objectives.” To put it another way, “if the goal is to maximize environmental benefits to people of color and low-income households, the optimal policy is not to incentivize adoption by these households, but rather to encourage adoption in the places that create the largest benefits.”
This summary was written with the assistance of Microsoft Copilot on July 2nd, 2025. Its content was edited and verified by EPIcenter staff and affiliates.
Read the full paper: https://www.journals.uchicago.edu/doi/epdf/10.1086/721604