Harvesting the Sun
According to the United States Energy Information Administration, there are approximately 2,500 commercial solar photovoltaic (PV) energy gathering and generating stations currently serving the nation’s electric grid. Most produce one- to five-megawatts (MW) of power. A five-MW facility requires roughly 40 acres of land. Some analysts maintain that, depending on how quickly the nation moves from non-renewable to renewable electricity, an additional 10-million acres of land could be needed by 2050. That’s an area greater than the land-mass of Massachusetts and New Jersey, combined. Although commercial solar arrays are frequently built on low-quality, low-impact sites, such as landfills, brownfields, abandoned mining land, and former industrial locations, they’re often placed on agricultural land, as well.
A couple of years ago, I wrote an article addressing solar development on agricultural land in the North Country. At the time, several large-scale PV energy generating projects were being considered in northern Franklin County, including a massive 150-MW power generating project on roughly 950-acres of land in the town and village of Malone, proposed by Minnesota-based Geronimo Energy. After the initial proposal encountered unwavering opposition from local residents, the application was scaled back to 50-MW, but resistance remained high and the project was eventually scrapped.
Like many others, I was extremely troubled by the size of the project, about losing such large tracts of sustainable agricultural land to industrial solar production. Not only was I apprehensive about the change of land use, I was concerned about land degradation, pollinator-habitat loss, and the possibility of other farmers eventually transitioning out of farming and into what I still see as industrial development.
A Compromise Solution
I know that solar PV development will contribute greatly to reaching both clean, renewable energy production goals and consumer demand, but when vegetation within and around an array is sprayed with herbicide and / or replaced by planting the land into a grass monoculture which is mowed regularly, or the entire site is covered with gravel, it can be devastating to existing ecosystems.
Several Cornell University researchers seem to have similar concerns. Nonetheless, they’ve come to see advancing solar PV energy production as an opportunity for both farmers and PV developers. And their solution is rather ewe-nique.
Todd Schmit is an associate professor at Cornell University’s SC Johnson College of Business’ Charles H. Dyson School of Applied Economics and Management. He’s also faculty director of Cornell’s Cooperative Enterprise Program, which is widely-recognized as a resource to enhance the skills of persons forming and leading cooperatives and group-action organizations in the Northeastern United States. He’s leading a three-year, $500,000 project, funded equally by Cornell University and the U.S. Department of Agriculture, to explore the potential economic and environmental benefits that could result from developing new and strengthening existing partnerships between farmers and solar energy developers.
In a recent article in the Cornell Chronicle, a weekly newspaper published by the University, Krisy Gashler, a writer for Cornell’s College of Agriculture and Life Sciences (CALS), quoted Schmit as saying, with regard to the maintenance of land that solar arrays are situated on, it’s, “a little ironic” that “we’re promoting renewable energy production and then, because we need to control the vegetation, we’re going out there with mowers that are using fossil fuels” (It seems to me that mowing through a solar array would be rather challenging, too.) “or spraying it with pesticides that are killing the plants.”
His solution — sheep. Because they’re small enough to control vegetative growth underneath the solar panels and won’t damage the solar installations by chewing cables or jumping on the panels, Schmit and others, including Lexie Hain, Executive Director of the American Solar Grazing Association, a nonprofit trade group that connects solar companies with shepherds, believe that sheep are the best-suited livestock species for what’s being called solar grazing or agri-voltaics; the combination of grazing livestock among the solar panels of arrays that are collecting and generating PV electricity.
Grazing benefits the soil, vegetation, and pollinators
Unlike mowing, rotational grazing of sheep can help maintain ecosystems, including vital habitat for native bees, butterflies (e.g. Monarchs), moths, and hummingbirds. And without the threat of noise or applications of toxic chemical herbicides, these pollinators, many of which are vital to sustainable forage, vegetable, and fruit production (e.g. alfalfa, soybeans, pumpkins, berries), all of which contribute substantially to our local economies and to our wellbeing, are able to thrive.
When using rotational grazing practices, sheep are continuously moved from one area of land to another, which allows more-recently-pastured areas to recover. This encourages the growth of deep perennial roots, which promotes better carbon sequestration. And when pasture-fed sheep poop, they put vital microorganisms back into the soil. Then they trample their manure into the ground, breaking it down into rich, organic, beneficial soil nutrients that promote even greater carbon sequestration.
Pollinator-friendly solar development can benefit managed pollinating insects, as well. Beekeepers might want to consider locating honeybee hives within a solar array, but not before assessing the site for suitability. Every location is different, with greater or lesser potential depending on site characteristics and the surrounding land.
Caption: Sheep grazing amid panels on a photovoltaic solar array site. Photo credit: Lexie Hain for Cornell Small Farms Program