A flock of sheep graze at a Maine solar farm.
A flock of sheep graze at a Maine solar farm. Credit: Michael Dennett / Courtesy

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From spring to fall, Michael Dennett spends his days transporting sheep from his family’s homestead in Jefferson, Maine, to graze at nearby solar farms. The flock that began as a gift for his wife — “really just [an] excuse for myself to get sheep,” he said — now works as a solar lawn service.

“If you’re a sheep, one of your biggest concerns … is eating grass in the predawn to, like, seven o’clock in the morning, and then hiding out for the rest of the day in the shade and just ruminating,” Dennett said. “They’ll spend the entire day under those panels, snoozing, walking around and kind of being lazy.” 

Add some cropland to the mix, and it’s the type of pairing that’s likely to become more important as demand for clean energy to meet state climate goals causes pressure to produce electricity on agricultural land. Finding ways for solar and agriculture to coexist could help ease land-use tension that is already becoming common across New England, advocates for the idea say.

Maine may be uniquely positioned for this emerging field, known as agrivoltaics or dual-use solar. Nationally, most successful projects so far have involved extras like solar grazing or pollinator habitat alongside panels at small farms with low-lying, hand-harvested crops — precisely the type of farms that dominate much of Maine’s agricultural sector.

Supporters say the concept has the potential to boost farmers’ revenue, but it’s also a risky proposition, which is why they say the state should fund a pilot project to gather more information about what works and what doesn’t when pairing solar and agriculture in Maine’s climate.

Piloting dual use

Maine has no more than a few small-scale agrivoltaics projects currently underway, including a study of how solar affects wild blueberry harvesters. But policymakers have eyed the potential for dual-use solar and agriculture with interest. 

A stakeholder group that looked at agriculture and solar siting issues as part of the state’s climate plan recommended funding for a dual-use pilot program, among other things. This proposal got broad support from state legislators this year but didn’t secure an appropriation for agency staff and resources after its passage.

This marked a setback for people like Ellen Griswold, the head of the Maine Farmland Trust. She sees dual-use solar and agriculture as an obvious win-win — providing economic and energy benefits to farmers, preserving a climate in which their crops can thrive, and making more land available to solar developers, all with fewer tradeoffs.

“I think there’s more hesitancy in Maine around dual use because it’s a newer concept … and so I think some people — farmers included, some agency officials — are a little bit more skeptical,” Griswold said. “To us, this pilot was really important because it’s a way of getting more projects established, and being able to … really gather the data and the research, to be able to sort of provide proof of concept, right, before we talk about ways of incentivizing it.” 

Farmland in general is often eyed for solar for the same reasons it’s good for growing plants — it’s flat, sunny, well draining and often accessible to outside infrastructure. When it comes to dual-use agrivoltaics, studies so far suggest that small, shade-loving crops on smaller farms, harvested by hand or with smaller equipment, are the best fit. 

These kinds of crops happen to be Maine’s specialty. Federal data shows the state’s highest-value commodity is potatoes, which grow low to the ground in Maine’s vast, relatively flat and rural northern regions. 

Agrivoltaics research offers good news for potatoes. One study from Belgium suggests that certain arrangements of solar panels can cool potato plants and help them grow in a warming and drier climate, and found that potatoes under panels adapted remarkably well to lower light conditions. The plants are not always harvested by hand, though, raising questions about panel designs.

A diversified farm sector

Maine also grows major crops of its iconic wild low-bush blueberries and hay, often used to feed dairy cows. The state does have its share of corn but is less singularly reliant on it than many Midwestern states, where the tall crop tended by large industrial equipment carries challenges for solar

The average Maine farm is less than half the size of the average farm nationwide. Whereas most farms across the country specialize in grains or cows, Maine’s largest source of farm sales in 2019 was “miscellaneous crops” — including lettuces, carrots, beans, peppers and strawberries, all low-lying, delicate plants that tend to be harvested by hand. 

But the devil will be in the details, said Nancy McBrady, who directs Maine’s Bureau of Agriculture, Food and Rural Resources — hence the need for pilot projects, like the kind that would have been studied under the proposal that stalled in the legislature. 

“In Maine, we mostly have diversified farms, and there’s going to be different types of vegetables, different types of seasons, different types of soils,” McBrady said. “Aroostook County [in northern Maine] is a lot of potato and broccoli. That might be a different pilot than, you know, the leafy greens that might be more in southern, central and Midcoast Maine. And so … I just think it would be really useful to have information about whether dual use fits the bill.” 

Some see a sense of urgency for collecting this information, as more and more solar is sited on agricultural soils. Maine’s climate action plan, which aims for the state to be carbon neutral by 2045, prioritizes a balance between renewable energy, healthy working lands and a robust local food system. 

But it’s a difficult balance to strike. Some conservation and farm advocates fear that without more guardrails to development, the state’s prime agricultural lands will remain too attractive for solar, and the income from a land lease too hard to pass up for small-scale farmers on tight margins. With a more balanced blend of solar and crops, farmers could reap those economic benefits with less sacrifice. 

“We’re very interested in seeing more dual-use projects,” said Eliza Donoghue, the policy director of Maine Audubon, which has done much of the work on solar siting data analysis to date. “We’re not about saying no. We’re about figuring out what’s the places that kind of do the least amount of harm from a land use perspective, and keep us marching forward towards our clean energy goals.”

Learning curve

Donoghue thinks the state is in a unique position to help answer this question with initiatives like the stalled pilot program. She was pleased, at least, that it got broad legislative support and could return in a future session. 

“You can’t necessarily just rely on developers like BlueWave to stick their necks out,” she said, referring to a Massachusetts company at the forefront of trying agrivoltaics in Maine. 

Ryan Walker, a development analyst at the firm, said one array the company plans to build in Benton, Maine, will have five acres with experimental rows of vegetables planted between the panels. Dennett’s sheep will graze the rest of the site.

“One thing I do really hope that we can get out of this project in Benton is kind of the baseline for that next iteration of the [state] pilot [program]. I think there’s a lot of people that were equally upset that it didn’t go through,” Walker said. “BlueWave is in a position to help inform, to help kind of lay the groundwork. We’ve been doing dual use — we’re familiar with it.” 

He hopes that groundwork will lead Maine to offer more incentives for agrivoltaics, like Massachusetts does, where the SMART program, or Solar Massachusetts Renewable Target, includes extra money for this kind of dual use. The state has had a university demonstration project for agrivoltaics for years and has found success in building arrays on cranberry bogs and vegetable farms

Absent that cushion of extra funding, Walker said they’re having to get “creative” with their upcoming Maine project’s design. Higher racking to raise the panels above the plants below can cost 15 cents more per watt in added materials such as steel, and these adaptations can increase labor costs too. 

The project and others like it, even those limited to grazing, have also posed a steep learning curve for state regulators like McBrady. She said this kind of novel permitting could be less challenging or at least move more quickly with more staff, which the scuttled pilot legislation would have funded.

She hopes projects like BlueWave’s will offer initial data that Maine could build on to grow more agrivoltaics and consider incentives in the coming years.

Questions or comments about this article? Contact us at editor@energynews.us.

Annie Ropeik

Annie Ropeik is a freelance journalist based in Portland, Maine. She spent about a decade as an award-winning public radio reporter and now works as the assistant director of the Mississippi River Basin Ag & Water Desk, an environmental reporting collaborative.