Solar plus cows = green dairy

Agrivoltaics is the use of land for both agriculture and solar-photovoltaic energy generation. Solar grazing is a variation where livestock graze in and around solar panels. The system looks at agriculture and solar-energy production as complementary to one another. By allowing working lands to stay working, agrivoltaic systems could help farms diversify income. Other benefits include energy resilience and a reduced carbon footprint.

Bradley Heins is an associate professor of organic-dairy management at the University of Minnesota-West Central Research and Outreach Center. He has since 2017 utilized agrivoltaics at the center’s research dairy farm. The center has a 110 head in a certified-organic system, and a 140 head in a conventional grazing system.

“We do research on pasture-based dairying and everything that surrounds dairy production here in Minnesota,” Heins said. “We got interested in agrivoltaics about 10 years ago.”

The project started by monitoring the dairy herd for energy usage. They learned exactly how much water was used and all elements of energy use on the farm.

“It’s part of a farm-wide initiative to make our entire farm carbon-neutral,” he said. “We extended our research to five other Minnesota dairy farms.”

The information gained from the energy-monitoring research allowed Heins to begin applying renewable-energy technologies – including agrivoltaics. He said the installation of solar panels into different paddocks on the farm was sometimes more common-sense than strict science. The biggest initial concern was preventing cows from damaging the panels while grazing beneath them. He hears that same concern from farmers via email at least five times each week. To determine how high to put the panels, he found the tallest cow in the dairy herd and decided how high it could reach with its tongue. He settled on an 8-foot panel height.

“Our first installation was 30 kilowatts divided in to two banks of 15 kilowatts,” Heins said. “We concreted the posts 6 feet in the ground.”