Russ Mattson

Solar Panels Outshine Ethanol in Energy and Environmental Impact, Study Finds

In a compelling comparison of land use and energy production, a recent analysis reveals that solar panels dramatically outperform ethanol corn in both energy efficiency and environmental sustainability. The findings suggest that converting farmland currently used for ethanol production into solar farms could yield transformative benefits for the U.S. energy landscape and ecological health.

Energy output: a stark contrast

The numbers are striking. One acre of ethanol corn produces about 10.3 megawatt-hours (MWh) of energy annually. In contrast, solar panels on the same acre can generate 394 to 447 MWh—a difference of up to 43 times more net energy. When factoring in the efficiency of electric vehicles (EVs) versus internal combustion engines, solar panels could deliver more than twice that number of the usable energy for transportation. Research recently published in April 2025 Proceedings of The National Academy of Sciences places the number at approximately 75 times the energy output of solar versus ethanol on the same acreage of farmland.

Unlike ethanol, which requires annual planting and harvesting, solar panels have a 25-year lifespan with minimal maintenance and only a slight decline in performance over time.

Environmental toll of ethanol farming

Ethanol corn farming is resource-intensive and environmentally damaging. Each year, it consumes:

•3.6 million metric tons of fertilizers, including nitrogen, phosphorus, and potassium.

•2.4 to 3.85 million metric tons of pesticides and herbicides.

•Significant amounts of fossil fuels for planting, harvesting, and refining.

Over a 25-year period, this adds up to 90 million metric tons of fertilizers and 60 million metric tons of chemicals—all contributing to greenhouse gas emissions, soil degradation, and water pollution.

The production of nitrogen fertilizer alone emits 40 million metric tons of CO₂ annually in the U.S., largely due to the energy-intensive Haber-Bosch process.

Land use and policy implications

Currently, 36 to 40 million acres of U.S. farmland—about 2% of the contiguous land area—are dedicated to ethanol corn. This land could be repurposed for solar energy, which requires less disruption and offers far greater energy returns.

The push for ethanol was driven by the Renewable Fuel Standard (RFS), established in 2005 and expanded in 2007. While intended to reduce greenhouse gas emissions, a 2016 report from the Government Accountability Office found the program unlikely to meet its goals due to limited production of advanced biofuels.

Water and soil degradation

Ethanol farming contributes to:

•Nitrate leaching, contaminating groundwater.

•Phosphorus runoff, causing algae blooms and eutrophication.

•Soil erosion, degrading land quality and harming aquatic ecosystems.

These impacts threaten biodiversity and water quality, including habitats for endangered species.

Solar panels: a cleaner path forward

Solar panels require no fertilizers, pesticides, or annual soil disruption. Their installation avoids the environmental costs of mining, processing, and transporting agricultural inputs. The energy payback time for solar panels is just 1 to 1.7 years, after which they produce clean energy for decades.

Even accounting for grid support needs like energy storage and backup systems, solar farms are far less damaging than ethanol corn production. A 2007 study by the National Renewable Energy Laboratory estimated that just 0.6% of U.S. land could meet national electricity needs—far less than the land currently used for ethanol.

Conclusion: a call for change

The data paints a clear picture: solar panels offer vastly superior energy efficiency and environmental benefits compared to ethanol corn. As the U.S. seeks sustainable energy solutions, shifting land use from ethanol to solar could be a game-changing move for both climate and conservation.

Russ Mattson PE is an electrical engineer and has over 30 years of experience in the electric power and utility industry. He is a member of Citizens Climate Lobby, providing research and presentations to several organizations on the need for energy storage and implications of renewable energy, and significance in Northeastern Minnesota.