The effort to make renewable energy generation, specifically solar panels, and agricultural production compatible on the same plot of land, has become known as Agrivoltaics. Such research was launched in 1981 by two German scientists, Adolph Goetzberger and Armin Zastrow, who determined that constructing solar panels so they are elevated about six feet above the ground rather than being placed directly on the ground can allow for crops to be cultivated below the solar panel array.
As part of the federal plan to ‘decarbonize’ the U.S. economy by 2035, the U.S. Department of Energy envisions that solar energy could provide as much as 40 percent of U.S. electricity by that year. The land area projected that would be needed to support a solar sector of that size would require 5.7 million acres of land. While that amount is a tiny fraction of U.S. land (0.3 percent) in the lower 48 states, it would need to be located near power transmission facilities and could add to recent encroachment on agricultural lands from other sources, such as spreading suburbs, expansion of low-density residential housing (so-called ‘ranchlets”), and the building of new roads and other public infrastructure. A 2020 report by American Farmland Trust found that between 2001 and 2016, 11 million acres of U.S. farmland and ranchland were converted to urban and highly developed land use (4.1 million acres) or low-density residential land use (nearly 7 million acres).
Over the last decade or so, U.S. scientists armed with funding from both the Department of Agriculture (through the National Institute for Food and Agriculture (NIFA) and the Climate Hubs) and Energy have undertaken research o determine the most compatible agricultural activities to pair with solar panel arrays, so as to reduce the pressure to fully convert agricultural lands to other uses. This effort represents a paradigm that allows for continued agricultural production while generating renewable energy, defying the current notion that installation of solar panels on farmland requires removing that land from agriculture entirely.
In general, the operation of the solar panels benefit from the transpiration of water vapor from plants growing underneath them, reducing cooling costs for the panels, while the plants or livestock raised underneath the structure benefit from the shade provided by the panels, which helps conserve moisture in arid climates. One of the impacts of this combination leads to reduced stress on plants and animals and higher production than would likely otherwise prevail absent that shade. For some crops, solar radiation is too intense during the summer in some regions to thrive, so the shade provided reduces the intensity and improves prospects for those crops. For example, leafy green vegetable crops, such as spinach, lettuce, and kale fall into this category. The value of this shade will only increase as average summer temperatures increase due to climate change.
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Expanded use of agrivoltaics can preserve working farmland while increasing solar power generation. Recent estimates published by the National Renewable Energy Laboratory (NREL), a DOE lab headquartered in Golden, CO, indicate that there are currently more than 340 agrivoltaics sites in the U.S., mainly pairing solar with pollinator habitat or small ruminant grazing (like sheep), across more than 33,000 acres and producing a total of 4. 8 gigawatts of solar energy. DOE has devoted more than $15 million to supporting these efforts in recent years, and USDA’s National Institute of Food and Agriculture (NIFA) has a Sustainably Co-Locating Agricultural and Photovoltaic Electricity Systems (SCAPES) project underway, led by the University of Illinois (Champagne-Urbana), partnering with the University of Arizona, Colorado State University, Auburn University, University of Illinois-Chicago, and NREL. Scientists working in USDA’s Northwest Climate Hub are also looking at ways to grow specialty crops under agrivoltaics.
Expansion of solar energy in rural areas not only helps replace fossil fuels such as coal in generating electricity, it also gives residents in those areas the benefit of decentralized power generation, reducing their dependence on a regional or national power grid, which are often unreliable, especially in developing countries. According to 2021 data collected by the United Nations Conference on Trade and Development (UNCTAD), only one-third of rural residents in least developed countries had access to any electricity. Even for those areas that have access to electricity, reliability of that access remains a critical concern. One estimate from 2020 from the nonprofit Energy for Growth Hub found that 3.5 billion people fall into the category of having unreliable access to electricity, defined as experiencing more than one outage per month consistently. Regions that face unreliable access to electricity are often deemed undesirable for manufacturing facilities, which are wary of facing production stoppages when outages occur unless they install some sort of backup system such as generators.
Several agrivoltaic pilot programs, in partnership with mainly European research centers and agencies, are underway on the African continent. Early results from 2022 were reported for the research phase of one such project in Algeria, (Watermed4.0), according to German research organization Fraunhofer ISE, one of eight organizations involved.
“We only had the first harvest of potatoes so far. Early data had some promising results: under the agrivoltaic installation there was an increase in yield compared with an uncovered reference field — about 16% more,” Brendon Bingwa, project manager of Agrivoltaics Africa at Fraunhofer, told DW. Additional work will provide more data and evidence, he added.
Earlier this year, the government of the Dominican Republic provided approval for construction of a 50 megawatt (MW) agrivoltaics project in the northern (Cerro Gordo) region of that island nation. The project will be built by a German solar energy company SUNfarming. Information on what agricultural activities will be co-located with this new facility is not yet publicly available.
