Overview
For years, large swaths of Wisconsin’s agricultural land have been used to grow corn for ethanol and soybeans used for biodiesel. These long-lasting practices can deplete and erode soils, and pollute our state’s surface and ground waters. This report examines how solar farms can work as an alternative energy source while delivering environmental and public health benefits when they’re properly sited, designed and managed.
Key Points
- Land Efficiency & Energy Output: Solar farms produce 100 times more net energy per acre than corn grown for ethanol and are a far more efficient use of land.
- Environmental Co-Benefits: Solar farms that replace conventionally farmed row crops like corn and soybeans reduce sediment and phosphorus pollution runoff into nearby lakes, rivers and streams by 75–95%, cut nitrate pollution, improve soil health and carbon sequestration, and provide needed habitat for pollinators.
- Public Health Improvements: Public health benefits from improved air quality due to solar electricity generation are estimated to be 5–10¢ per kWh, which exceeds the cost of generating the electricity itself (3–4¢ per kWh).
Summary
Using agricultural land to produce energy in Wisconsin is nothing new. We devote 1.5 million acres of farmland in our state to grow corn for ethanol, and we produce about 25 million gallons a year of biodiesel from soybeans, accounting for another 700,000 acres. But growing these crops can come with significant environmental costs. Conventionally-grown corn and soybeans used for fuel production are produced in annual, monocropping systems—an intensive practice of cultivating a single crop year after year on large tracts of land, which requires substantial applications of fertilizers and pesticides to maximize production. These practices can lead to nutrient-depleted soils, erosion, and pollution of nearby waterways and drinking water supplies.
Today, we are seeing a new kind of energy production taking root on Wisconsin’s agricultural land—solar farms. In Wisconsin and across the Midwest, solar farms are almost exclusively integrated into agricultural landscapes, which are relatively flat and already cleared of natural vegetation. Not only does integrating solar into farmland provide a steady source of income for family farms, it reduces the negative environmental impacts from conventional crop production and minimizes the conflicts with wildlife habitat that occur when solar is built in undeveloped, natural areas.
Important Takeaways
- Land Use Impact: Less than 2% of Wisconsin’s farmland is needed for solar farms to reach carbon neutrality—far less than the land used for biofuel crops.
- Water Protection: Solar sites can reduce agricultural runoff dramatically, improving water quality and protecting drinking water from nitrate contamination.
- Soil & Carbon Benefits: Deep-rooted vegetation under panels boosts soil health and can increase carbon sequestration by up to 65%.
- Biodiversity Gains: Solar farms provide 300% more pollinator habitat compared to current agricultural land, reversing biodiversity loss caused by monocrop farming.
- Health & Climate Synergy: By replacing fossil fuels, solar energy reduces air pollution and greenhouse gases, offering measurable public health and climate resilience benefits.
