Increasing the use of solar energy presents a significant opportunity to reduce carbon emissions in the United States. A study led by Francesca Dominici from Harvard University reveals that while fossil fuels accounted for 60% of electricity generation in 2023, solar energy only represented 3.9%. Enhancing solar capacity is shown to not only cut CO2 emissions but also decrease harmful air pollutants that affect health. The research utilized extensive data analysis to demonstrate the specific benefits of solar energy, identifying key regions where investments would yield the most significant reductions in emissions.
The study highlights a stark imbalance in the U.S. energy mix: in 2023, fossil fuels accounted for 60% of electricity generation, while solar contributed just 3.9%, according to the U.S. Energy Administration. Expanding solar could significantly reduce not only CO2 emissions but also the harmful air pollutants responsible for adverse health outcomes, such as fine particulate matter. The study analyzed hourly electricity generation, demand, and emissions data from the Energy Information Administration over a five-year span starting in mid-2018. Researchers developed a high-resolution statistical model to simulate how added solar generation impacts CO2 emissions both locally and in neighboring regions across 13 U.S. energy zones.
For example, in California, a 15% midday increase in solar output reduced emissions by 147.18 metric tons in the first hour and an additional 16.08 metric tons after eight hours. These delayed reductions had not been quantified in prior studies. The analysis also identified which regions would benefit most from increased solar capacity. States like California, Florida, Texas, and the Midwest were found to deliver outsized emission cuts per unit of solar investment, while places like New England and Tennessee showed lower returns. Moreover, regional spillover effects were substantial. A 15% boost in California’s solar production led to daily CO2 reductions of 913 metric tons in the Northwest and 1,942 metric tons in the Southwest, underscoring the importance of interregional collaboration on clean energy deployment.
“Our study offers policymakers and investors a roadmap for targeting solar investments where emissions reductions are most impactful and where solar energy infrastructure can yield the highest returns,” said lead author Arpita Biswas, assistant professor of computer science at Rutgers University. “From a research perspective, our findings also demonstrate the power of harnessing large-scale, high-resolution energy data to generate actionable insights.”