Once upon a time, a common argument by solar energy skeptics was that expansive solar farms would overtake large swaths of American farmland, to the eventual detriment of American farmers seeking to grow crops or raise livestock. The industry has grown and matured in such a way that not only rebuffs this concern but shows how solar energy systems can actually be very beneficial to the agricultural industry.
What is Agrivoltaics?
Agrivoltaics is a term used to describe the marriage between solar power generation and agricultural production. The U.S. Department of Energy defines it as “agricultural production, such as crop production, livestock grazing, and pollinator habitat that exist underneath solar panels and/or in between rows of solar panels.”
The concept underscores the multi-faceted life-giving qualities of the Sun. Plants and livestock not only benefit from sunlight in the traditional way, but sunlight absorbed by solar panels is used in part to support on-site agricultural production, such as powering irrigation systems and agricultural equipment.
Unlike typical utility-scale solar farms, agrivoltaics involves the solar panels being much higher off the ground and strategically “clustered” in ways that optimize sun/shade exposure for optimal crop production. Contrary to popular belief, few crops thrive on all-day sun exposure. Solar panels on the other hand thrive with lengthy sun exposure. Agrivoltaics allows for the best of both worlds.
Photo Source: N-Sci Technologies
The temperature moderating effects of the elevated solar panels also have crop production benefits. Air and land underneath the panels is cooler in the summer, which helps insulate crops from drought impacts as moisture is more easily retained in the soil. The elevated panels also benefit from the cooling effects of having ample air flow above and below them, since solar panels lose efficiency when their surface temperatures get too hot.
A 2019 study by the U.S. Department of Energy’s National Renewable Energy Laboratory’s (NREL) documented numerous food production, water savings, and energy production benefits of agrivoltaics. The study found that solar panels were kept 16°F cooler by evaporation from the crops below, which was enough to increase energy production by 2%. The crops below the solar panels that were tested were found to be 100%-300% more productive, depending on the species, while solar panel shade cover reduced irrigation-water use by 15% and overall water consumption by over 150%. Pretty impressive numbers all around.
The wide-ranging benefits of agrivoltaics ultimately mean more cash in the pocket of farmers. Not only do crop yields increase and maintenance costs decrease, but they are often able to benefit from dual income streams from a solar land lease arrangement and improved crop production.
Solar grazing is a phenomenon that few could have conceived of once upon a time, but now, the practice is routinely employed to the collective benefit of animal, farmer, and solar operator. According to the aptly named American Solar Grazing Association (ASGA), the U.S. has over 15,000 acres of sheep-maintained solar sites.
Once you can get past the odd visual, relying on sheep to graze on the land where massive solar arrays sit is a no-brainer. Grazing sheep munch on grasses and weeds, which helps to optimize solar panel efficiency by removing shade threats and keeping the panels otherwise unobstructed. This reduces the need for traditional mowing and landscaping, which can help to prevent unwanted structural damage to the solar arrays and helps to keep stray grass clippings and dirt from soiling the surface of the panels. We also implicitly associate solar energy systems with carbon reduction and environmental benefits, so ditching gas-powered lawnmowers and chemical herbicides for grazing sheep is a meaningful shift that can amplify the broader benefits of solar energy production.
For their troubles, the sheep get a comfortable supply of food to munch on and ample protection from the sun and weather elements underneath the solar panels.
Photo Source: American Solar Grazing Association
The cost-savings for all parties involved is another reason to like the solar-sheep arrangement. The solar operator no longer has to worry about maintenance fees associated with traditional landscaping and potential damages from mowing mishaps or overgrown vegetation. Meanwhile, the sheep farmer receives a steady income stream for the use of their sheep without sacrificing meat, dairy, or wool production capabilities. According to the ASGA, solar operators typically pay farmers $250-$750 per year for an acre of land to be grazed.
Incorporating pollinator-friendly habitats into solar farm sites is another aspect of the agrivoltaics movement that has far-ranging benefits.
The decline in pollinator populations – especially among bees – is well-documented. Habitat loss, climate change impacts, and insecticide use are some of the main challenges that pollinators continually face these days.
By incorporating native plant habitats on solar sites, great progress can be made to support critical pollinator populations. Other associated benefits like reducing erosion and runoff issues, and promoting overall biodiversity are an added bonus. When accompanied with pollinator-friendly vegetation management practices, like eliminating insecticide use, solar sites can help to foster pollinator activity on-site and in the surrounding area. The participating farmer and neighboring agricultural sites stand to benefit from all of the increased pollinator activity given the obvious role that pollination plays in crop production.
Photo Source: Fresh-Energy
The Environmental Protection Agency (EPA) has general guidelines to protect pollinators from harmful insecticides, and there are no shortage of pollinator-friendly organizations out there that promote best practices in supporting pollinators in your home garden, school, business, etc. Many states are now implementing their own pollinator-friendly solar farm standards to incentivize pollinator habitats specifically on solar farm developments. Minnesota was the first state to do just that back in 2016, when then Governor Mark Dayton signed the Pollinator Friendly Solar Act into law. This first-of-its-kind legislation outlined voluntary standards and benchmarks that participating solar sites can meet in order to achieve recognition as a “pollinator-friendly” solar location. Several other states have followed Minnesota’s lead and developed their own voluntary standards to certify solar sites as pollinator-friendly.
Photo Source: Fresh-Energy
We’ve seen consumers’ pro-renewable preferences influence all sorts of industries and the honey industry is no different. Not only are pollinator-friendly solar sites becoming more common as a way to benefit farmers and vulnerable pollinator populations, but honey producers are also realizing the appeal of marketing honey harvested on solar farms. Companies like Minnesota-based Bare Honey are embracing this promising market opportunity and showcasing the multiple layers of economic and environmental benefits of solar-based honey production.
The cross-cutting benefits of solar energy never cease to amaze us. The emerging prominence of agrivoltaics is but the latest manifestation of the broad benefits associated with solar energy. Not only can solar energy lead the way to powering the world in a more sustainable way, but it can totally transform the way that we produce food. Imagine a future where acres of farmland is covered with solar panels and high yielding crops; grazing sheep and abundant honey producers. Global de-carbonization goals will require wholesale changes across many industries. The ongoing innovations in the agriculture industry and the emergence of agrivoltaics are a great example of how solar energy will continue to shape (and improve) the future.
Cover Photo Source: Enel Green Power