Can dual-use solar panels provide power and share space with crops?


Over its 150-year history, Paul Knowlton’s farm in Grafton, Mass., has produced vegetables, dairy products and, more recently, hay. Changes in farm use depended on changing markets and a variable climate. Recently, however, Mr. Knowlton has added a new type of cash crop: solar power.

For Mr. Knowlton, a fifth-generation farmer and current owner, it was an easy call. He had already installed solar panels to supply electricity to his house and barn. When a real estate agent came knocking to see if he was interested in renting a small piece of his land for a solar panel, “she sowed the seed that I could do more,” Mr Knowlton said.

Knowlton looked at several companies, but was very impressed with BlueWave Solar, a Boston-based developer that focuses primarily on solar installations and battery storage, which helps feed excess electricity into the power grid. Soon, two small, largely unused plots of land housed low-to-the-ground panels that generate electricity. This year, Mr. Knowlton’s farm will go one step further: in a third plot, solar panels will share space with crops so both can thrive.

This approach is called agrivoltaics – a portmanteau of agriculture and voltaic cells, which transform solar energy into electrical energy. Also called dual-purpose solar, the technology involves adjusting the height of solar panels up to 14 feet, as well as adjusting the spacing between them, to accommodate equipment, workers, crops and grazing animals. . The spacing and angle of the panels allow light to reach the plants below and have the added benefit of protecting those crops from extreme heat.

The electricity generated is uploaded to the grid, usually via nearby substations. Although some of the electricity may travel to the host farm, the projects are designed to provide general purpose electricity. And such solar installations provide an alternative source of income in the form of payments to landowners like Mr Knowlton or reduced rental payments for sharecroppers.

BlueWave has focused primarily on designing the projects and then selling them to the companies that build and oversee them. The Grafton project, on Mr. Knowlton’s farm, for example, is now owned by the energy company AES Corporation.

“Agrivoltaic not only advances the clean energy imperative, it is essential to keeping farms running,” said John DeVillars, one of BlueWave’s three co-founders and chairman of the board.

Dual-use solar power became attractive more than a decade ago because “large installations in the middle of nowhere won’t solve all of our power problems – transporting that power can be very expensive,” he said. Greg Barron-Gafford, a biogeographer. and assistant professor at the University of Arizona. In many parts of the country, farms are located in peri-urban areas, transitional areas between rural and urban land. Their proximity to high-use metropolitan areas makes open farmland particularly suitable for solar panels, but in the past, without any co-existing agriculture, this type of placement can create conflict over whether food or energy production should prevail.

In a study by AgriSolar Clearhouse, a new collaboration aimed at connecting farmers and other landowners to agrivoltaic technology, the facilities were also shown to promote growth by protecting crops from rising temperatures and helping to water conservation. While the technology is still in its infancy in the United States compared to countries in Europe, where the technology has been used for more than a decade, federal regulators as well as academics and developers are scrambling to address this disparity.

Early results are promising, said Garrett Nilsen, acting director of the US Department of Energy’s Office of Solar Energy Technologies. “There’s a project in Arizona where they’ve seen a three-fold increase in crop yields when under this type of system and up to 50% reduction in irrigation needs” because the panels provide energy. shadow, he said. Additionally, the plants under the panels release water into the air, which cools the modules, creating what Mr Nelson described as a “symbiotic relationship between the plants and the panels”.

BlueWave’s first project to come online is a 10-acre farm in Rockport, Maine, now owned and operated by Navisun, a solar energy producer. Wild blueberry cultivars have been planted under solar panels, which will generate 4.2 megawatts of electricity; the project is estimated to produce 5,468 kilowatt hours per year, equivalent to the amount of electricity needed by about 500 US homes.

Unlike Massachusetts, Maine does not offer significant incentives for using solar power, so there was a 10-15% cost premium over similar projects, which BlueWave absorbed, Mr. DeVillars said. (This practice is consistent with the company’s status as a so-called B-Corporation, which requires a commitment to social and environmental goals.)

Other players clearly see the potential of agrivoltaics: on May 12, Axium Infrastructure, an investment management company, announced its acquisition of BlueWave. Trevor Hardy will remain as chief executive and Eric Graber-Lopez will continue as chairman, while Mr. DeVillars will become chairman emeritus.

Mr Hardy said the sale would allow BlueWave to expand to own and operate, not just develop, solar installations and storage batteries. Ultimately, he said, the sale “puts us in a stronger place for dual purpose.”

“Farmers work for the long term,” he continued. “It’s more compelling to drive down the farm roads and sit with the owners at their kitchen table and say we develop, own and operate the facility. And the technology’s potential goes far beyond blueberries; agricultural uses have included vineyards and shrimp farming.

BlueWave is not the only agrivoltaic developer. According to the Germany-based Fraunhofer Institute for Solar Energy Systems ISE, five megawatts of electricity were produced by these systems in 2012; in 2021, 14 gigawatts of electricity were generated in dual-use systems, roughly equivalent to the electricity needed by about two million U.S. homes each year, according to a spokeswoman for the department’s technology office Energy. And the technology is changing rapidly; in the few years following the installation on Mr. Knowlton’s farm, adjustable panels that could move to maximize the capture of sunlight, for example, were developed.

“It doesn’t always pay to be a pioneer and sometimes it’s very difficult,” said Hardy, who grew up in a South African farming family. Finding suitable sites – where there is sufficient sunlight and near a substation or other electrical infrastructure – can be difficult. Opposition from neighbours, especially when the signs are visible from other homes or even from the road, is not uncommon.

Indeed, BlueWave was one of many defendants named in a lawsuit involving an agrivoltaic plan project in Northfield, Mass. A state court recently ruled that the neighbor had standing to challenge the development. One of the plaintiffs, Christopher Kalinowski, said his particular fear was that his views would be hampered and “the area would lose farmland”. (Mr. Hardy declined to comment on the litigation.)

Additionally, some chapters of the environmental nonprofit Audubon have spoken out about the technology’s potential effect on wildlife. Michelle Manion, vice president of policy and advocacy for Mass Audubon, said that while his organization has supported renewable energy, including solar power on farms, “first we want to maximize the placement of ground-based solar power on some of our lands that are the least ecologically sensitive” .

And there are general concerns that even with dual-purpose solar panels, arable land could be lost, although BlueWave says land can be reallocated to pure agricultural uses once solar leases – typically 20 to 30 years – expire.

But one of the biggest hurdles is cost. The skyrocketing cost of steel has a direct effect on agrivoltaic’s emphasis on raising panels 10 to 14 feet. “For every foot you go up, you have to get two feet into the foundation,” Hardy explained. “It’s a tough industry when you think about what we need to do to meet climate goals. But we stay the course.

Ultimately, however, it all depends on the taste of the cultures: if the flavor or even the appearance deviates too far from that of traditional products, the technology will be a difficult sell. But in an early study, researchers from the University of Arizona’s Biosphere 2 Agrivoltaics Learning Lab found that tasters preferred potatoes, basil and squash grown with agrivoltaics. The beans, however, can take a while: the small sample of tasters preferred the traditional version.


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