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Can Dual-Use Solar Panels Provide Power and Share Space With Crops?

Companies like BlueWave are betting on it. But the technology has its critics.

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

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

Mr. Knowlton looked at several companies but was most impressed with BlueWave Solar, a developer in Boston that focuses primarily on solar installations and battery storage, which allows excess electricity to be fed to the power grid. Soon, two small parcels of largely unused land were home to low-to-the-ground panels that produce power. This year, Mr. Knowlton’s farm will go one step further: In a third parcel, solar panels will share space with crops so that both can thrive.

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

Solar panels on Paul Knowlton’s farm in Grafton, Mass. Cattle will graze below the panels, which rise to 14 feet above the ground. Credit…Tony Cenicola/The New York Times
Mr. Knowlton prepares the soil between the panels before he plants butternut squash and lettuce. Credit…Tony Cenicola/The New York Times

The electricity generated gets uploaded to the grid, typically through nearby substations. While some of the electricity may find its way to the host farm, the projects are devised to provide power for general use. And such solar installations provide an alternative source of revenue in the form of payments to landowners like Mr. Knowlton or a reduction in lease payments for tenant farmers.

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

“Not only do agrivoltaics advance the clean energy imperative but they are critical to maintaining working farms,” said John DeVillars, one of BlueWave’s three co-founders and the chair of the board of directors.

Dual-use solar became of interest more than a decade ago because “big installations in the middle of nowhere aren’t going to solve all of our energy problems — transporting that energy can be very expensive,” said Greg Barron-Gafford, a biogeographer and an assistant professor at the University of Arizona. Farms in many parts of the country are in peri-urban areas, zones of transition from rural to urban land. Their proximity to high-use metropolitan areas makes open farmland particularly suitable for solar arrays, but in the past, without any coexisting agriculture, that sort of placement can set up a conflict over whether food or energy production should prevail.

In a study by AgriSolar Clearhouse, a new collaboration to connect farmers and other landowners with agrivoltaic technology, the installations were also shown to foster growth by shielding crops from increasing temperatures and aiding with water conservation. While the technology remains in its infancy in the United States compared with countries in Europe, where the technology has been used for over a decade, federal regulators, as well as academics and developers, are working to remedy that disparity.

Early results are promising, said Garrett Nilsen, the acting director of the Solar Energies Technologies Office of the U.S. Department of Energy. “There’s a project in Arizona where they’ve seen a threefold increase in crop yields when they are underneath this kind of system and up to a 50 percent reduction in irrigation requirements” because the panels provide shade, he said. Additionally, the plants under the panels release water into the air, which cools the modules, creating what Mr. Nilsen described as a “symbiotic relationship between the plants and the panels.”

BlueWave’s first project to go live is a 10-acre farm in Rockport, Maine — now owned and operated by Navisun, a solar power producer. Wild blueberry cultivars have been planted below solar panels, which will produce 4.2 megawatts of power; the project is estimated to produce 5,468 megawatt-hours annually — equivalent to the amount of power needed for roughly 500 U.S. households.

Unlike Massachusetts, Maine does not offer significant incentives for the use of solar power, so there was a 10 to 15 percent premium on costs when compared with similar projects, which BlueWave absorbed, Mr. DeVillars said. (That 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 are clearly seeing the potential of agrivoltaics: On May 12, Axium Infrastructure, an investment management firm, announced its acquisition of BlueWave. Trevor Hardy will remain as chief executive and Eric Graber-Lopez will continue as president, while Mr. DeVillars will become chairman emeritus.

Mr. Hardy said that the sale would allow BlueWave to expand so that it will own and operate, not just develop, solar installations and battery storage. Ultimately, he said, the sale “puts us in a stronger place for dual-use.”

From left, Trevor Hardy, John DeVillars, and Eric Graber-Lopez of BlueWave Solar, on Mr. Knowlton’s farm. Credit…Tony Cenicola/The New York Times

“Farmers work on a long-term basis,” he continued. “It’s more compelling to drive up farm roads and sit with the owners at their kitchen tables and say that we develop, own, and operate the installation.” And the technology’s potential goes well beyond blueberries; agricultural uses have included vineyards and shrimp farming.

BlueWave is not the only agrivoltaics developer. According to the Fraunhofer Institute for Solar Energy Systems ISE, based in Germany, five megawatts of power were produced through these systems in 2012; by 2021, 14 gigawatts of power were generated in dual-use systems — roughly equivalent to the electricity necessary for approximately two million U.S. households annually, according to a spokeswoman from the Department of Energy’s technologies office. And the technology is evolving rapidly; in the few years since the installation at Mr. Knowlton’s farm, adjustable panels that can move to maximize the capture of sunlight, for example, have been developed.

“It doesn’t always pay to be a pioneer and it’s very challenging at times,” said Mr. Hardy, who grew up in a South African farming family. Finding suitable sites — where there is sufficient sun and proximity to a substation or other electrical infrastructure — can be difficult. Opposition from neighbors, especially where panels are visible from other homes or even the road, is not uncommon.

Indeed, BlueWave was one of several defendants named in a suit over a proposed plan for agrivoltaics in Northfield, Mass. A state court recently ruled that the neighbor had the standing to challenge the proposed development. One of the plaintiffs, Christopher Kalinowski, said that among his concerns were that his views would be obstructed and that “the area will lose farmland.” (Mr. Hardy declined to comment on the litigation.)

Panels are spaced apart to allow the planting of crops. The background parcel is reserved for only solar panels. Credit…Tony Cenicola/The New York Times

In addition, some chapters of the Audubon nonprofit environmental organization have been vocal about the technology’s potential effect on wildlife. Michelle Manion, the vice president of policy and advocacy for Mass Audubon, said that while her organization supported renewable energy, including solar within farming operations, “we want to maximize the placement of ground-mounted solar on some of our lands that are the least ecologically sensitive first.”

And there are general concerns that even with dual-use solar panels, arable land may be lost, though BlueWave says that the land can be reverted to pure agriculture uses once the solar leases — typically 20 to 30 years — expire.

But one of the most significant obstacles is cost. The skyrocketing cost of steel has a direct effect on agrivoltaics’ emphasis on raising the panels 10 to 14 feet. “For every foot, you go up you need to go two feet into the foundation,” Mr. Hardy explained. “It’s a challenging industry when you think of what we need to do to reach climate goals. But we’re staying the course.”

Ultimately, though, everything depends on how the crops taste: If flavor or even appearance strays too far from that of traditional produce, the technology will be a hard sell. But in an early study, researchers at the Biosphere 2 Agrivoltaics Learning Lab at the University of Arizona found that tasters preferred the potatoes, basil, and squash grown with agrivoltaics. Beans, however, may take some time: The small sample of tasters preferred the traditionally grown version.

Article by: Ellen Rosen

Via: https://www.nytimes.com/2022/06/28/business/dual-use-solar-panels-agrivoltaics-blue-wave-power.html

platio solar

Platio Solar Introduces Improved Solar Modules For Solar Pavement

At a recent industry event in Germany, Hungarian company Platio Solar revealed a very useful new solar module that can be used for flooring or outdoor spaces. Given some bad experiences solar ground installations have faced, especially solar roadways, it makes sense that people would be skeptical, but this new design is not only improved but not aimed at getting pounded by automobiles.

“They rely on a new frame structure that provides better protection for the glass surface,” Marketing Manager Helga Ruscsák told pv magazine. “They can be used for pavement, terraces, driveways, sidewalks, parks, bicycle roads, marinas, and low traffic roads, as well as for other industrial and off-grid applications.”

Here’s a video with an older version of the panels:

While these panels in the video look like they’d be a great way to provide more solar power in places where there’s not a lot of space to put them on rooftops, the company has been working to improve them to make them more durable and protected. This means that people will be able to more confidently install them in places where people walk, bike, and maybe even do some limited driving.

The innovative thing about these panels isn’t as much the solar cells as much as what they’re housed inside of, but that doesn’t mean you don’t have some great options for the parts inside. Variants come with a variety of commercial solar cells built-in, including both polycrystalline and monocrystalline. The size is always the same, though at 359 mm x 359 mm x 41 mm, weighing about 6.5 kilos.

Are you a PV nerd or professional and want the gritty details? Platio gave the press those, so we’ll pass them along! Polycrystalline variants come with 156 mm x 156 mm cells with 18.6% efficiency, and (under ideal conditions) produce 18.2 W. Open-circuit voltage is 2.56 volts with a short-circuit current of 8.9 amps. Monocrystalline variants of the panel are 22.3% efficient, and have an open-circuit voltage of 2.72 volts, with a short-circuit current of 8.89 amps. The size of the mono cells is 158.7 mm x 158.7 mm.

The housings are made from tough stuff, too. Thick, tempered glass covers the solar panels, measuring a whole centimeter thick. Decorative patterns, presumably with some traction-improving texture to them, are etched into the glass itself so you don’t have to worry about bike tires and the treads of shoes peeling or grinding an anti-slip coating away.

platio solar

PV Magazine says the frames are made of a “polymer composite based on low-density polyethylene (LDPE) and high-density polyethylene (HDPE) with matrix-forming material.” I’m no materials specialist, but that sounds like some durable stuff that won’t be bothered by being tread under foot. Perhaps more importantly, it’s made of 100% recycled material, which is great for lowering the environmental impact of producing these things!

You’re probably wondering how much weight something made from glass and plastic can handle, and fortunately, that information is available. Each cell can handle two tons of weight on a single wheel of a vehicle, and the whole vehicle can weigh up to 8 tons. If they’re so tough, some readers may wonder why we don’t take another crack at making solar roads again, but that’s not the plan.

“We do not intend to build solar highways or solar roads with our products,” Ruscsák told PV Magazine.

And, they’re probably right to not plan on that. Even though they’re so tough, let’s keep in mind that semi-trucks can weigh as much as 40 tons, and produce even more severe forces when it comes to hitting bumps, going down hills, etc. But, having plenty of spare strength for sidewalks, bike paths, and maybe something like a driveway or minor street is definitely a good thing.

Article by: Jennifer Sensiba

Via: https://cleantechnica.com/2022/06/21/hungarian-company-introduces-improved-solar-modules-for-solar-pavement/

Featured image and other image by Platio Solar.

quantum well solar cells

New Quantum Well Solar Cell Just Set A World Record For Efficiency

Scientists keep on pushing the efficiency of solar panels higher and higher, and there’s a new record to report: a new solar cell has hit 39.5 percent efficiency under the standard 1-sun global illumination conditions.

That 1-sun marker is simply a standardized way of measuring a fixed amount of sunlight, and almost 40 percent of that radiation can now be converted into electricity. The previous record for this type of solar panel material was 39.2 percent efficiency.

There are more types of solar cells around than you might have realized. The type used here, triple-junction III-V tandem solar cells, are often deployed in satellites and space vehicles, though they have plenty of potential here on solid ground as well.

“The new cell is more efficient and has a simpler design that may be useful for a variety of new applications, such as highly area-constrained applications or low-radiation space applications,” says physicist Myles Steiner, from the National Renewable Energy Laboratory (NREL) in Colorado.

The ‘triple-junction’ part of the equation is important in terms of the efficiency of the solar cell. Each junction concentrates on a particular part of the solar spectrum range, meaning that less light is lost and left unused.

Further efficiency gains were made through the use of so-called ‘quantum well’ technologies. The physics behind them is quite complex, but the general idea is that the materials are carefully chosen and optimized, and made as thin as possible. This affects the bandgap, the minimum amount of energy required to excite electrons and get the current flowing.

In this case, the three junctions are made up of gallium indium phosphide (GaInP), gallium arsenide (GaAs) with some extra quantum well efficiencies added, and gallium indium arsenide (GaInAs).

“A key element is that while GaAs is an excellent material and generally used in III-V multijunction cells, it does not have quite the correct bandgap for a three-junction cell, meaning that the balance of photocurrents between the three cells is not optimal,” says physicist Ryan France from the NREL.

“Here, we have modified the bandgap while maintaining excellent material quality by using quantum wells, which enables this device and potentially other applications.”

Some of the improvements added in this latest cell include an increase in the amount of light absorbed without any corresponding voltage loss. Several other technical tweaks were also made to minimize limitations.

It’s the highest 1-sun efficiency of any solar panel cell ever recorded, though we’ve seen higher from more intense solar radiation. While it takes time for technologies to make their way from the lab into actual products, the potential improvements are exciting.

The cells also recorded an impressive 34.2 percent space efficiency, which is what they should achieve when put to use in orbit. Their weight and resistance to high-energy particles make them particularly suited for this task.

“As these are the highest efficiency 1-sun solar cells as of this writing, these cells also set a new standard for achievable efficiency across all photovoltaic technologies,” write the researchers in their published paper.

The research has been published in Joule.

Article by: David Nield

Via: https://www.sciencealert.com/scientists-just-set-a-new-record-for-solar-cell-efficiency