The development of new solar farms demands a limited and precious resource - land - which is also critical to ranchers and graziers raising livestock. This week, we spoke to Stacie Peterson, Executive Director of the American Solar Grazing Association, about solar grazing, an approach to multi-purpose land use that supports clean energy, ecological health, economic growth, and happy sheep.
The deployment of utility scale solar has often required clearing vegetation and then using fossil-fuel-powered mowers or toxic herbicides to prevent overgrowth. To reduce these harms, solar grazing is a dual land use approach where livestock is taken to solar farms to manage the vegetation that can grow and interfere with the panels. Solar grazing reduces maintenance emissions, provides a revenue stream for local ranchers, and promotes soil health.
Solar grazing is a type of targeted grazing, which is, “the controlled application of specific livestock at a designated season, duration, and intensity to achieve specific landscape and vegetation management goals”. Those goals often include weed control, fire risk reduction, and wildlife habitat enhancement. Solar grazing specifically refers to livestock grazing on solar farms, or, under and around solar arrays. According to the American Solar Grazing Association (ASGA), other terms associated with solar grazing include agrivoltaics (the co-location of agriculture and solar), agrisolar, agri-pv, or rangevoltaics. One grazier compares solar grazing to silvopasture - or, grazing under trees - “Just with metal trees”.
Sheep have been found to be an excellent match for the needs of solar grazing. Sheep are nimble and can work around solar installments, eliminating work that, without re-designing or raising solar panels, can be difficult for humans. The benefits of solar grazing extend beyond vegetation management: sheep have been measured to have lower body temperatures, both in their wool and skin, when they’re shaded by solar panels. Additionally, forage quality and moisture content are higher in the shade where water in the soil evaporates more slowly. Sheep have been shown to drink less water during solar grazing, which reduces water needs for graziers. Solar grazing also eliminates competition for land use between solar developers and graziers.
Solar grazing has been expanding across the country for the last decade; however, long-term studies on the effects of grazing on biotic and abiotic factors - as well as changes in cost over time - have not been widely conducted. One of the highest costs in solar grazing is transportation and logistics, so in places like the US’s Northeast where most solar farms are around 11 acres, moving sheep makes grazing less affordable. In regions with large or interconnected farms, that cost is reduced; Stacie reports that many sheep are born and live out their lives on one farm. Solar grazing is often viewed as just “mowing with sheep” - not as an active agricultural practice. The American Farmland Trust emphasizes that, on the contrary, “It’s a way to grow food, build soil, create habitat, and generate renewable energy at once.”
Stacie emphasizes that grazing - even in areas where animals have to be rotated between sites - contributes less fossil fuel emissions than mowers that run on diesel. Mowers and weed-whackers have other side effects: blades have a tendency to “throw” rocks, or pick up and eject rocks, which can damage panels and add costs to operation. Also, using any machine powered by combustion increases fire risk.
There’s a demographic shift supported by solar grazing. Often, the greatest financial hurdle to a grazing operation is buying or leasing pasture; for young people who won’t inherit pastureland, solar grazing lowers the barrier to entering the industry. Stacie says that polling done by ASGA shows a lower average age of participants compared to the national average, which sits around 65. Also, a greater proportion of women are involved. Another upside: solar graziers are contracted by solar farms - meaning, instead of paying to lease or buy land, they’re being paid for their service - which adds economic opportunity. On the climate side, Stacie underscores improvement in overall soil health, but especially carbon sequestration. The use of agrivoltaics tends to improve public acceptance of large-scale solar, a key strategy for reducing the country’s dependence on fossil fuels.
Stacie Peterson is the Executive Director of the American Solar Grazing Association. She was a developer of the AgriSolar Clearinghouse for the Department of Energy and the Director of Energy Programs at the National Center for Appropriate Technology. Her environmental research includes the development of a protocol for domestic dogs to serve as bioindicators of metal contamination and cleanup efficacy.
For a transcript of this episode, visit https://climatebreak.org/grazing-livestock-on-solar-farms-with-stacie-peterson/
Ethan: I’m Ethan Elkind, and you’re listening to Climate Break– climate solutions in a hurry. Today’s proposal? Grazing livestock under solar farms to increase soil health, cut emissions from maintenance, and protect local communities. We spoke to Stacie Peterson, Executive Director of the American Solar Grazing Association.
Ms. Stacie Peterson: The main climate benefit of solar grazing is the impacts to the soil health. It is increasing soil carbon and, because of all of this and the increased water retention, it’s having a huge impact.
Ethan: Solar grazing is a form of agrivoltaics, a practice that combines solar panels and agriculture on the same land. Beyond boosting soil carbon storage, Peterson says swapping out mowers for sheep can also cut fossil fuel emissions.
Ms. Peterson: You're decreasing it incredibly. I mean, sheep are not using any kind of diesel, right? The only diesel you'd be using would be to get them to the site, and a lot of these sheep live their whole lives there.
Ethan: Peterson explains how sheep can also help reduce wildfire risks.
Ms. Peterson: Plants grow up and around the solar panels, and that can cause fire risks, especially in some place like California. So solar grazing pairs perfectly for this. Sheep really like to climb under and around the panels. They wanna be in the shade, so they like to eat the forage exactly where it's needed.
Ethan: For agricultural communities dealing with a changing climate, Peterson says solar grazing can build economic resilience.
Ms. Peterson: We're actually keeping those lands in agricultural production. With these solar sites, you're not only having access to these lands, you're being paid by a contract as the vegetation management company for this, so that's improving the farm viability for the grazer and for his community.
Ethan: To learn more about solar grazing, visit climatebreak.org.