Can Pollinator-Friendly Solar Energy Work for Bees and Farms?

Just two years earlier, the Woods’ solar energy story might have turned out differently. In 2014, solar energy companies were approaching Midwest farmers to develop prime farmland into conventional gravel-and-turf-grass-based solar projects, according to Rob Davis, director of the Center for Pollinators in Energy at clean energy non-profit Fresh Energy in Saint Paul.

“Anticipating the unintended consequence of this kind of energy transfer sent shivers down our spines,” Davis says. Minnesota was in the process of moving from 150 to 8,000 acres of ground-mounted (as opposed to roof-mounted) solar. Not only would such conversions of farmland to energy-only operations have negative consequences for pollinators; they’d also take arable land out of production—the opposite direction US agriculture needs to head to meet food needs as climate change continues to negatively affect our crop yields.

Davis discovered that in the UK, some solar energy parks were planting seed mixes developed by an ecologist. Online, inspiring photos showed innocuous-looking solar panels plopped into vibrantly blooming meadows. Were such initiatives worth pursuing in the States?

Davis contacted renowned University of Minnesota bee expert Marla Spivak to ask. “She was pretty direct and emphatic and helped us understand that county, state, and federal governments and authorities were not investing enough money in conservation programs, and that private sector money for creating habitat would be meaningful,” says Davis. He got a similar answer from an entomologist with expertise in monarch butterfly populations, which have plummeted by 90 percent.

Fresh Energy began an awareness campaign that attracted stakeholders eager to discuss pollinator-friendly solar solutions, including Minnesota’s Board of Water and Soil Resources; Audubon Minnesota; the Minnesota Farmers Union; the Minnesota Corn Growers Association. In 2016, thanks to the efforts of this consortium and other players, the state became the first to pass a pollinator-friendly solar energy law, which mandates standards companies must meet to label themselves “pollinator-friendly.” Five other states—Illinois, Maryland, New York, South Carolina, and Vermont—have since followed suit; six more have written standards without the legal framework. As of this writing, there are 5,000 acres of pollinator-friendly solar energy from Oregon to Vermont.

The Benefits of Pollinator-Friendly Solar

The potential benefits of pollinator-friendly solar energy are many and varied. Yes, they provide on-site habitat and forage for beleaguered bees, butterflies, and other insects. These insects provide pollinator services to both agricultural crops planted on nearby farms, and to those that have been purposefully planted right at the edges of a field full of solar panels—a technique known as agrivoltaics. Having lots of pollinators around, to visit flowering plants over and over, actually increases crop yields.

These systems can also support rotational grazing of livestock and honeybee apiaries. And yes, they keep arable land as arable land, so that it can be used to grow things in the future; and also add to it energy and ecosystem services that improve life for everything on our planet—Davis calls this “stacking benefits.”

The ecosystem services that come about through the (re)introduction of native plants to a landscape improve soil health; help remove carbon from the atmosphere and its store in the ground; reduce flooding; and clean air and water. Larger arrangements of solar panels than what the Woods’ host on their property, for example, which are naturally situated on larger plots of meadow, make for prime foraging ground for animals like pheasants. Additionally, the plants underneath a solar array—raised two to 10 feet off the ground—help cool the panels, boosting their efficiency. Some more elevated models also allow for food crops to be grown directly beneath them.

Although native seeds can be expensive, it’s less work to prepare the ground for a meadow than it is to purchase and lay down gravel or turf grass. This lowers the cost, as does a meadow’s reduced maintenance—requiring maybe one mow a year. Jordan Macknick, lead energy-land-water analyst at The US Department of Energy’s National Renewable Energy Laboratory (NREL), says the extra money for seed is made back in a couple of years.

Searching for Stats

Still, what’s missing is hard data—on everything from whether the meadows beneath pollinator-friendly solar panels do improve the health of insect populations, to what seeds thrive in various climates. The former has mostly been informed by parallel research from the restoration ecology sector that shows native-plant benefits to pollinators.

The latter is very much a work in progress. As Davis points out, Vermont’s agriculture (blueberries, apples) differs vastly from Illinois’s (corn, beans, pumpkins); so does each state’s native plant network and the insects that rely on it. As a result, determining standards for the steps an energy company must take in order to use the “pollinator-friendly” designation has been a challenge, requiring input from an army of experts with wide ranging knowledge.

Broadly, the standards are loose and flexible; scorecards give points for high diversity of native plants, selections that bloom throughout the year, and best management practices. Regionally, would-be solar-adopters are advised to work with local plant specialists to determine the right seed mix—in Vermont, for example, this could include Black-eyed Susans, Little blue stem grass, and coneflowers.

Still, there’s a lot to know about what works and doesn’t. Which is why NREL is studying nine seed mixes, comprised of hundreds of species of plants, at 21 solar energy test sites across the country. One of these is located at a Clif Bar bakery in Twin Falls, ID. Helping to figure out what the right mix of native seeds for this region of high desert is a way for the company to meet its sustainability goals, says Clif Bar vice president of environmental stewardship Elysa Hammond. But demonstrating pollinator-friendly solar could have wider influence. “If utilities understand they can do something that benefits farmers and the environment, that will be a whole new way to think about energy policy,” Hammond says

University of Illinois professor of entomology Adam Dolezal, who worked on Illinois’s standards and legislation, thinks that pollinator-friendly solar energy has its limitations. The state’s agricultural land leans toward conventionally farmed monocultures of corn and soy beans, which provide very few nutritional resources to pollinators needing a variety of multi-season flowers to forage from.  “If we can work patches of restored habitat in to extreme agricultural landscapes, is that the best-case scenario? Probably not,” Dolezal says.  However, research has shown that bees with access to small areas of prairie restoration, right across the street from, say, a cornfield, collect more pollen and showed increase fat stores.  And we also know, says Dolezal, “that the alternatives of turf grass and gravel are not going to have any benefit.”

Which means that, with the solar energy sector growing at a rapid clip of 14 percent a year, pollinator-friendly models still provide an important opportunity, says energy and research specialist at the Center for Biological Diversity Greer Ryan. On top of the climate benefits of switching off of fossil fuels, “We can be creative about where and how we build to protect the environment.”

Meanwhile, back in Mount Hope, WI, the solar meadow on the Woods’ property will soon be blooming for its second season. “I was so happy they didn’t just spread gravel,” says Sharon Wood. “I haven’t seen bees and butterflies around here for years, and if this brings them back, that’s a good thing.”