It’s not your average solar farm.
The glassy panels stand in a meadow. Wildflowers sway in the breeze, bursts of purple, pink, yellow, orange and white among native grasses. A monarch butterfly flits from one blossom to the next. Dragonflies zip, bees hum and goldfinches trill.
As solar projects unfurl across the United States, sites like this one in Ramsey, Minn., stand out because they offer a way to fight climate change while also tackling another ecological crisis: a global biodiversity collapse, driven in large part by habitat loss.
The sun’s clean energy is a powerful weapon in the battle against climate change. But the sites that capture that energy take up land that wildlife needs to survive and thrive. Solar farms could blanket millions of acres in the United States over the coming decades.
So developers, operators, biologists and environmentalists are teaming up with an innovative strategy.
“We have to address both challenges at the same exact time,” said Rebecca Hernandez, a professor of ecology at the University of California, Davis, whose research focuses on how to do just that.
Insects, those small animals that play a mighty role in supporting life on Earth, are facing alarming declines. Solar farms can offer them food and shelter by providing a diverse mix of native plants.
Such plants can also decrease erosion, nourish the soil and store planet-warming carbon. They can also attract insects that improve pollination of nearby crops.
Pollinator friendly solar can pay off for business, too, potentially saving money and giving projects an edge for approval at a time when communities are increasingly wary of vast solar farms. Developers are taking note.
But there’s a broad spectrum of pollinator friendliness and little agreement on what efforts should count. Standards are often nonexistent. Some big projects are limiting pollinator habitat to tiny corners of their sites. Ecological value varies widely.
Communities may not understand the difference, and corporate marketing may exaggerate. That’s led to accusations of greenwashing.
Pollinator habitat on solar farms is “a serious work in progress,” said Scott Black, executive director of the Xerces Society for Invertebrate Conservation, a nonprofit group that is working on an effort to bring some clarity by certifying solar sites.
“It’s not fair if some people are truly stepping up to do this right and another company is barely doing anything and saying they’re pollinator friendly,” he said.
‘If you build it, will they come?’
On a recent morning at the solar meadow in Ramsey, it was time to count insects.
Among the rows of panels at the 18-acre site, Lee Walston, a landscape ecologist at Argonne National Laboratory, found the plastic flags marking one of his research tracts. He set off with two students through plants that brushed above their knees, eyes scanning below.
“There’s a sweat bee,” Mr. Walston said, pointing to a bee that glistened metallic green.
“I’ve got a moth and two hoverflies,” one of the students said. The other recorded observations.
In solar pollinator habitat, Minnesota was an early leader among states. Since 2017, funded by the Department of Energy, Mr. Walston has been studying sites there and throughout the Midwest.
“If you build it, will they come?” he asks in his research. So far the answer is a resounding yes, if you grow the right plants.
In a study published late last year, his team found that insect abundance had tripled over five years on test plots at two other Minnesota solar sites. The abundance of native bees grew twentyfold.
The results come amid a global decline of wildlife that leaders are struggling to address. Some of the most well-known insect species are in trouble: Later this year, the federal government is expected to rule on whether to place monarch butterflies on the Endangered Species List. North American birds, for their part, are down almost 30 percent since 1970.
But at this site, called Anoka County Solar, acoustic monitoring has documented 73 species of birds, presumably attracted by the buffet of seeds and insects. Some build nests in the structures supporting the panels.
Mammals are showing up, too. Mr. Walston checked a trail camera before leaving, hoping to discover the occupant of a remarkably large burrow: A fox, he thought, or a badger. No luck.
(It’s trickier to make solar sites friendly to large wild animals, in part because developers are nervous to let them near expensive infrastructure, but efforts are underway there, too.)
What makes this meadow possible is the height of the panels. A prairie restoration firm had told ENGIE, the owner and developer, that taller panels would allow for a sharp increase in native vegetation species, providing much more ecological diversity, said John Gantner, the director of engineering and delivery for ENGIE’s smaller-scale sites.
The price of the additional steel and the native seeds were “insignificant to the overall project cost,” Mr. Gantner said. Over the life of the project, ENGIE has found, pollinator friendly landscaping actually saves money because it needs far less mowing.
“We’ve calculated and ran the numbers and there’s significant savings,” Mr. Gantner said.
But many other projects, especially big utility-scale sites, avoid the taller panels. Margins are razor tight, developers say, and the higher costs up front feel too risky or even insurmountable.
That limits the options for landscapers.
“When I sit down and do a utility-scale solar project seed mixture, and I look in my toolbox, it’s like I have a rusty screwdriver and a roll of duct tape,” said Peter Berthelsen, a wildlife biologist who runs a company that specializes in creating habitat for solar projects.
So he scours his sites for any patch of land that doesn’t have panels. In those areas, which he said often encompass 10 or 20 percent of a given site, he plants a native pollinator mix of at least 40 species.
Under the panels, he and others often turn to Dutch white clover. While that provides some nectar for native insects like bumblebees, it’s considered better forage for honeybees, an introduced agricultural species. (Honeybees pollinate plants and make a delicious food for people, but ecologists generally don’t view them as wildlife in need of conservation.)
The more plant diversity allowed under the panels, Mr. Berthelsen said, the more environmental benefits will follow. Still, he cautioned, it’s important to “not let the pursuit of perfect be the enemy of doing something good.”
In measuring ecological value, the starting point is fundamental, scientists say. Replacing a field of row crops with solar panels and clover would provide a net benefit for pollinators, even without a mix of native species. On the other hand, no amount of high-quality seeding will match the ecological value of an intact ecosystem, especially in places where solar panels would require the removal of trees or shrubs.
Nationwide, it’s unclear what portion of solar farms include any kind of pollinator habitat. The federal project that Mr. Walston is part of has a running rough count of just under 24,000 acres. That’s compared with about 600,000 acres of currently operating large-scale sites across the country, according to the Solar Energy Industries Association, with a sharp increase expected over the next couple decades.
Then there’s the question of developers delivering on their commitments.
‘Not enough plants here’
Four years ago, a project was in development outside Sacramento. Described as “a pollinator friendly solar farm,” even its name signaled ecological beauty: Wildflower Solar. “Fostering biodiversity and boosting crop yields for the community,” a brochure read.
Developed by Lightsource BP, which is co-owned by the oil and gas giant, one aspect of the project raised questions from the beginning: Diverse pollinator vegetation was restricted to a garden on roughly 1.5 acres of the 67 acre site, about 1 percent of the project, in an area underneath transmission lines.
Throughout the panels, the company said it would use a seed mix of five native grasses and a smaller amount of native clover. That’s better than turfgrass, scientists say, but it doesn’t come close to the benefits from a more diverse assemblage. At the time, Lightsource BP defended its decision to a reporter for Inside Climate News, claiming that the entire site would be pollinator friendly.
Dr. Hernandez of U.C. Davis wished the project was going further. But she was pleased about one thing: a pledge to plant more than 200 native trees and shrubs along the perimeter, on the edge of a rural neighborhood. The plantings would not only create a more attractive view for the community, but also a corridor of habitat for wildlife.
But when she drove by last year, Dr. Hernandez said, she didn’t see any plantings.
In May, Dr. Hernandez accompanied me to Wildflower. The 200 trees and shrubs, promised both in planning documents submitted to the county and in marketing materials, were nowhere to be seen. Instead, the area was overgrown with invasive grasses and noxious weeds like yellow star thistle, which the state has spent millions trying to eradicate. After tromping through shoulder-high, dried-out vegetation, we found the remnants of a few plantings underneath.
“There’s not enough plants here,” Dr. Hernandez said. “And there’s no vegetation management.”
In an interview and follow-up emails, representatives of Lightsource BP said the trees and shrubs had been planted around fall 2020 and blamed droughts for their demise. They said they had instructed their landscaping contractor “to solicit replacement plantings and a robust, multiyear care plan for the landscaping trees and shrubs.” They did not say why the problems had not been addressed earlier.
Alyssa Edwards, who leads environmental affairs and governmental relations for Lightsource BP, said the company was a leader in the industry when it came to biodiversity.
“It really is in our ethos, and it’s embedded into the way we develop, construct and operate projects,” Ms. Edwards said. The company’s Facebook page regularly posts about its commitment to biodiversity. But she was clear: “We do not raise our panels to accommodate pollinators.”
At least 15 states have some kind of pollinator scorecard, meant to guard against greenwashing by awarding points for various ecologically valuable features. States do not require certification, but in many cases a project must achieve a certain score to declare itself pollinator friendly.
But the scorecards have been criticized as both too weak and too stringent. On one hand, they typically lack a mechanism for monitoring, simply relying on a company’s promises. On the other, developers say some of the standards are not feasible given realities on the ground. When some local governments started mandating use of the scorecards, some in the industry pushed back, saying it could have a chilling effect on solar development.
A new nongovernmental certification is in the works, a partnership between the Electric Power Research Institute, an industry-funded research group, and the Xerces Society. But the effort has proceeded slowly as partners try to find compromise between the needs of the solar industry and the needs of nature. The current draft would require 15 percent of vegetated areas on the site to include a diverse mix of native, pollinator friendly vegetation.
“On one side, we want to protect biodiversity and pollinators. On the other side, we need the most efficient way to get kilowatt hours to customers, to power at the plug,” said Jessica Fox, a conservation biologist with the electric power institute. “So we’re doing this work now to find where is a middle space.”
Among the challenges developers face: Higher upfront costs are no guarantee of greater savings. Landscapers with the right experience can be hard to find, as can native seeds.
Not every site is even appropriate for pollinator habitat, Ms. Fox noted. And even when they are, each has its own distinct characteristics. Climate, topography, soil type and other factors all change the palette of possibilities. For example, not far from Wildflower, at a site called Rancho Seco Solar II, the presence of endangered salamanders made it difficult for scientists to prepare the soil before planting a research plot with three native seed mixes.
The site’s owner, the Sacramento Municipal Utility District, sees more promise in creating a hedgerow of more than 300 native shrubs and perennials along the perimeter of the site, which can increase habitat connectivity without complicating matters with the solar panels.
Given the urgency to tackle both global warming and biodiversity loss, solar sites should be experimenting with promising solutions, scientists say.
“We’re in this infancy, the infancy of trying to make this work and to do better,” Dr. Hernandez said. “And we need to get there faster.”
