By Bradley J. Heins, Extension Specialist, Dairy Management and Professor, Dairy Management, West Central ROC, University of Minnesota ** full list of authors at the end of the article*
Solar farms are anticipated to cover 5.7 million acres to meet rising demand for renewable energy. Land available for solar farm development is limiting this expansion. Efforts to increase public acceptance of solar farm development include coupling conservation and agriculture practices. Despite growing interest, there is limited science-based data summarizing the impacts of solar panels on plant and livestock growth and development in the Upper Midwest.
Farmers are increasingly interested in combining agriculture with solar energy production, a practice known as agrivoltaics. This approach allows farmers to use the same land for both farming and generating electricity, which can help make solar farms more acceptable to local communities by providing additional benefits, such as agricultural products or wildlife habitats. For dairy farmers, agrivoltaics offers an exciting opportunity. Traditionally, dairy farming relies heavily on fossil fuels for various tasks, from cooling milk to running tractors. But by installing solar panels on their land, farmers can generate their own electricity, potentially reducing their reliance on fossil fuels and cutting down on energy costs. This could help make dairy operations more sustainable and cost-effective.
There was no research that had investigated the use of a ground-mounted solar system to provide shade for dairy cows and to determine the effects on dairy cows. Therefore, our team wanted to investigate the effects of shade from solar photovoltaic panels on the production, health, and behavior of pastured dairy cows. During the summer of 2024, a 500-kW ground mount solar array was added to the existing pasture for shade for grazing dairy cattle (Figure 1). The Morris dairy operation milks 275 cows twice daily and is representative of a mid-size Minnesota dairy farm.
Twenty-four crossbred cows were assigned to one of two treatments: shade from solar PV or no shade. The no shade cows did not have access to any shade on pasture. A SmaXtec bolus was placed in the reticulum of the cow and recorded internal body temperature as well as activity and drinking bouts of cows. Daytime ambient elevated temperatures during the study ranged from 27 to 34°C. Furthermore, seven forage species and three mixes of grass and legume species were planted underneath two different solar sites and 1 control site without shade. Forage crops included alfalfa, field peas, meadow fescue, orchard grass, red clover, BMR sorghum-sudan grass, white clover and three meadow fescue, orchard grass, and legume mixes with either alfalfa, red clover, or white clover. The objective was to evaluate forage biomass and nutritive value of crops, grasses and legumes grown under different agrivoltaic conditions.
Respiration rates for shade and no shade cows were similar during the morning hours, but during the afternoon, shade cows had lower respiration rates (66 breaths/min) than no shade cows (78 breaths/min). Milk, fat, and protein production were not different for cows whether they had shade or no shade. Hourly body temperature results show that no shade cows had greater internal body temperatures (+0.6°C) than shade cows from 1pm to 12 midnight. Between milking times (10am to 8pm), the shade cows had lower internal body temperatures than no shade cows. All cows had similar body temperatures during the nighttime hours.
Forages grown under solar panels produced less biomass at the 30kW (564 kg/ha) and 50kW (446 kg/ha) solar sites compared to a control site (1,100 kg/ha). Forage biomass and nutrient values varied based on the solar array design and amount of sun exposure. Although less biomass was produced in the agrivoltaic sites compared to the control, forages were of high quality based on similar or higher crude protein, fiber content and digestibility, and mineral levels of the forages in the 30kW and 50kW sites.
Based on the results of this study, cows may have sacrificed grazing time to stand in the protection of the shade. Future research with our solar panels will investigate the reproductive performance of the cows, and long-term effects on milk, fat, and protein production, body weight, body condition, and animal health and well-being. Our study indicates that agrivoltaics may provide an acceptable method of heat abatement to pastured dairy cows, as well as generating electrical energy for farmers, thus reducing the carbon footprint of the dairy operation. Agrivoltaics in the form of forage production grown underneath ground-mounted photovoltaic systems can provide a suitable feed source for organic livestock production, a renewable energy source for farms and economic opportunity for farmers.
A new agrivoltaics project was started in 2023 at our grazing dairy. The project will provide new frameworks that will develop and model innovative structural designs for a combination solar shade for pastured livestock during the summer and windbreaks/snow fence for cattle during winter. Economic impacts of the agrivoltaics system and land productivity from solar farms will drive the adoption of solar photovoltaic systems on farms. The study indicated that agrivoltaics may provide an acceptable method of heat abatement to pastured dairy cows, as well as generating electrical energy for farmers, thus reducing the carbon footprint of the dairy operation. Future research with our solar panel will investigate the reproductive performance of the cows, and long-term effects on milk, fat, and protein production, body weight, body condition, and animal health and well-being. Economic impacts of the agrivoltaic system and land productivity from solar farms will drive the adoption of solar photovoltaic systems on farm. The project, funded by Minnesota Environment and Natural Resources Trust Fund, will involve evaluating these new strategies to assess results and make recommendations to farmers. Overall, agrivoltaics has the potential to make dairy farming more sustainable, efficient, and profitable, offering farmers new ways to improve their operations.
By Bradley J. Heins, Extension Specialist, Dairy Management and Professor, Dairy Management, West Central ROC, University of Minnesota, Sabrina Portner, Extension Educator, University of Minnesota Extension, Kirsten Sharpe, Researcher, University of Minnesota WCROC, Eric Buchanan, Researcher, University of Minnesota WCROC, Mike Reese, Director of Renewable Energy, University of Minnesota WCROC
Posted: to Organic Production on Fri, May 16, 2025
Updated: Wed, May 14, 2025
