Originally published on collegian.csufresno.edu.
The National Renewable Energy Lab projects that traditional solar farms could cover almost two million acres by 2030. However, to improve land-use efficiency, farmers and scientists have developed methods for combining land use for both solar energy production and agricultural purposes, a system known as agrivoltaics. According to a recent study by Oregon State University, converting just 1% of U.S. farmland to agrivoltaics would generate 20% of the electricity needed to power the entire country and produce $35.7 billion in annual revenue. In this article, Green Development LLC, a leading developer of utility-scale solar power in Rhode Island, provides an overview of agrivoltaics and solar grazing and how the synergy of agriculture and energy can improve the lives of farmers and farmworkers, increase crop yield, and saves water.
Protects Plants from Harsh Midday Heat and Saves Water
As any gardener will attest to, plants can be very particular about the amount of sunshine they require. Too much sun causes the molecules responsible for photosynthesis to absorb more energy than they can handle and generate reactive oxygen species, ultimately killing the plant. This is one reason crop rotations are seasonally dependent, and many cannot tolerate the constant, direct sunlight that summer brings. Plants that are more heat tolerant will make up for surpassing their “point of light saturation” by increasing their water intake.
In addition, to make the most efficient use of the land for both energy generation and agriculture, solar panels can block shade-loving crops from the harsh midday heat. By installing solar panels four to five meters above ground, spaced out at seven to nine meters apart, tractors and other farm equipment can be accessed more efficiently than standard ground-mounted solar installations. The solar panels in agrivoltaics systems can either be positioned statically in the most optimum way for the plants or be governed by intelligent software that rotates the panel positions based on real-time conditions of the sun. These algorithms model how much sunlight the plants are receiving under fluctuating shade, monitor the flow of rain from the solar panels to the ground, and anticipate temperature and humidity requirements based on weather forecasts and other factors.
Controlling the amount of direct sunlight the crops receive allows for irrigation events in agrivoltaics systems to support crop growth for days instead of just hours. It also helps extend the growing seasons by reducing heat and drought stress in the summer and keeping more heat in during the fall. This overall process improves food production, particularly for plants that tolerate partial shade well.
Agrivoltaics Can Work with a Wide Variety of Crops
Leafy greens, tomatoes, broccoli, and barley are excellent candidates for agrivoltaics, though some varieties may perform better than others. Our Kids’ Farm in Richmond, Rhode Island, has been able to extend its growing season for shade-loving plants, such as lettuces, arugula, and mixed kale, by planting them under a standard-height solar array. French company Sun’Agri has been able to reduce vineyard water usage with its agrivoltaics installations. The University of Arizona has successfully grown tomatoes, chard, kale, cabbage, and onions under solar panels in the Sonoran Desert. They are optimistic about adding other shade-loving crops, like alfalfa, yam, taro, cassava, sweet potato, and lettuce.
Steady Income for Farmers
Farmers can benefit from the added income by selling the solar power they generate to power companies or leasing their land to solar developers to build the solar arrays. Unlike the prices for farm products, which fluctuate with commodity prices, the income generated from building solar farms on agricultural farms is steady revenue for farmers. In North Carolina, solar companies are paying annual rents that are more than triple the average rent for crop and pasture land.
Better Conditions for Farmworkers and Free-Range Animals
Solar panels provide much-appreciated shade for grazing animals and help promote the growth of pasture grass — a concept called solar grazing. As existing solar arrays are mounted low to the ground, sheep and other small-to-medium sized livestock are the best-suited animals for solar grazing. Farmworkers appreciate the shade, too: data shows that agrivoltaics can keep skin temperature about 18 degrees cooler for farmworkers. This is particularly important in hotter regions, where farmworkers suffer from dehydration, heat strokes, and death. Farmworkers die from heat-related illnesses at 20 times the rate of the rest of U.S. laborers.
The Future of Solar and Agriculture Fusion
Agrivoltaics presents a unique opportunity to synergize our need for renewable energy with many beneficial factors for farmers, farmworkers, free-range farm animals, and crop yield. More research is needed to understand the benefits of agrivoltaics truly, but the initial results are promising. By pursuing innovative ways to integrate renewable energy into other seemingly unrelated facets of our economy, we take a few steps closer to a more prosperous future.
About Green Development LLC
Green Development LLC is the leading developer of large-scale renewable energy projects in Rhode Island, specializing in wind, solar, and battery storage. In addition, the company delivers significant energy savings to municipalities, quasi-public entities, nonprofits, and other qualified entities through the virtual net metering program while providing long-term lease payments to landowners and farmers.
Since 2009, Green Development has been instrumental in transforming the energy mix in Rhode Island to clean, reliable energy. The company has developed more than 70 MW in solar and wind capacity, with plans to add 75 MW in 2021. Green Development is devoted to preserving farmland, reducing water and air pollution, increasing energy security, and creating local jobs. Current wind and solar sites reduce carbon emissions equivalent to using 8,557,790 gallons of gas each year.