Tag Archive for: AgriSolar

AgriSolar News Roundup: Agrisolar in Nova Scotia, Albania Agrisolar Law, World Soil Day 

Experts Say Agrisolar Could Benefit Nova Scotia 

“Solar energy advocates believe agrivoltaics could have many benefits in Nova Scotia. There are now more than 10,000 solar installations in Nova Scotia, according to the non-profit group that’s trying to build up solar infrastructure in the province. That’s up from 8,000 this time last year and just 200 in 2018. ‘Farmers in Nova Scotia have been real leaders on the uptake of solar,’ said David Brushett, board chair of Solar Nova Scotia. ’There’s a real strong interest among the agricultural sector in solar.’” – cbc.com 

New Albania Law Recognizes Agrisolar Development 

“The Kuvendi – the Parliament of Albania – changed the Law on the Pasture Fund. Lawmaker Edona Bilali from the ruling Socialist Party of Albania submitted the bill, citing numerous requests for photovoltaic and wind installations. In the solar power segment, PV panels now need to be mounted at least five meters above the surface to allow cattle grazing.” – balkangreenenergynews.com 

Agrisolar Recognized on World Soil Day 

“Solar energy and agriculture are proving their relationship is a mutually beneficial one. As technology improves and more farmers adopt solar solutions, we can expect to see even more innovative applications emerge. Solar energy is ushering in a new era of sustainable agriculture. 

As we mark World Soil Day (Dec. 5), it’s also worth celebrating that it is also a transformative force to be reckoned with in farming!  Here are 5 key ways that solar energy is revolutionizing farming practices around the world.” – earthday.org 

Case Study: Fiddlehead Farms

By Anna Richmond-Mueller, NCAT Energy Analyst 

Known as the “Sunshine State,” it’s easy to see why solar energy production should be right at home in Florida. The state is also one of the country’s top agricultural producers, raising billions of dollars worth of specialty crops and livestock each year. Agrivoltaics seems like a natural fit and a potential option for farmers and ranchers looking to diversify their revenue and support the growth of renewable energy in the state. At Fiddlehead Farms, owners Walter and Sharon Liebrich are embracing that potential, working hard to bring an agrisolar pilot project and educational space to life in Tallahassee.   

Walter’s interest in agrivoltaics is deeply rooted in his passion for renewable energy. In 1998, Walter was the High School Florida State Champion in Policy Debate when the yearlong topic debated the pros and cons of increasing the use of renewable energy in the U.S. Then in 2004, he earned a Master’s degree in Public Administration from the Askew School of Public Administration at Florida State University. At the time he was in graduate school, connecting a solar project to the grid was an opportunity largely limited to big businesses and utilities. His thesis advocated for solar net metering and interconnection policies for individuals and small businesses in the state, something that wouldn’t be in the Florida statutes until 2008. After earning his degree, Walter went on to work as a Senior Policy and Budget Analyst in the Governor’s Office for 15 years before transitioning into the solar industry. He is also on the Board of Directors for ReThink Energy, a local nonprofit dedicated to community outreach and education for Floridians as the city moves towards its clean energy goals. Through his work with ReThink Energy, Walter joined the Tally 100% Together Coalition and helped to pass a unanimous city commission resolution in 2023, committing Tallahassee to 100% renewable energy by 2050.  

The Liebrich Family.

Walter and Sharon both share a passion for farming and gardening, as well. After meeting in 2009, they started pursuing those passions together by cultivating an edible landscape at their home, with the goal of having their child pick the vegetables for that night’s dinner right in their own backyard.  The 0.3-acre primary residence in midtown Tallahassee is home to many varieties of citrus, blueberries, blackberries, fig, pears, mangos, kiwi, avocado, pineapple, peaches and more. They also have a year-round seasonal garden comprised of anything from broccoli, kale, and arugula to tomatoes, peppers, and squash. They began their apiary work in 2019, successfully cultivating bees to help support the worldwide food shortage. By 2023, their impressive dedication to renewable energy and specialty crop production led them to set their sights on a new goal: creating an agrivoltaic community solar project.  

Around the same time, the Tallahassee City Commission unanimously adopted the 100% renewable energy resolution, and Walter and Sharon poured their entire life savings into the purchase of a 5-acre piece of property adjacent to a new public park and cypress preserve in Tallahassee. Their vision for the newly purchased land includes a 1-megawatt agrivoltaic array that would provide locally grown produce for the community, while also helping bring the city closer to its 100% renewable energy goals. However, before that vision can come to life, they must overcome some regulatory barriers for solar in the City of Tallahassee. “Anything from 100 kilowatts to 75 megawatts is all basically regulated under the same umbrella, which is extremely cost-prohibitive,” Walter explains. Projects in this size range are required to undergo thousands of dollars of grid and impact studies before an array can be built. Fortunately, thanks to all his volunteer work with ReThink Energy and Tally 100%, Walter has cultivated a network of professionals in the city and utility, who all want to see his vision become a reality. He understands the importance of building bridges further from home, as well. From the National Renewable Energy Laboratory to the Florida State Director of the Office of Energy, Walter continues to make connections that will be vital in the project’s success. He continues to work with city officials towards a positive change in the regulations for mid-size projects, as well.  

The solar aspect of the pilot project might still be in the early stages, but there’s already a lot happening at the site on the agricultural front. The unkept land was mostly filled with invasive species and heavily vining plants when Walter and Sharon bought it. Clearing invasive species, wild vines, and other biomass on-site is necessary for the project’s implementation. That doesn’t mean that the site will be clear cut and bulldozed, though. Instead, selected areas will be cleaned up while others will remain largely as they are. Any brush and invasive trees that do need to be removed are being used to create biochar, which Walter then uses to construct the raised beds for the row crops. Kale, broccoli, peppers, tomatoes, squash, pineapple, banana, and kiwi will all make an appearance throughout the year. The site is also home to wild sparkleberries and persimmon bushes. These plants will be incorporated into the site’s agricultural production by grafting their close, more familiar cousins onto the existing bushes. Japanese Fuyu persimmons will be grafted onto the wild persimmon bushes, and blueberries will be grafted onto the sparkleberries. Once the plans for solar panels are solidified, they will be built around and above the raised beds and bushes already in place. 

Biochar raised beds.

Looking ahead, Fiddlehead Farms hopes to make a positive impact on both local communities and the agrisolar research community. Most of the food grown at the site will be donated to Second Harvest of the Big Bend, a nonprofit fighting food insecurity in the region. When it comes to research, Walter understands the importance of having test sites and welcomes collaborations with universities, research institutions, and solar companies. He hopes to install a variety of racking types, tracking abilities, and panel heights across the site. Fiddlehead Farms is also a nonprofit organization, and anyone interested in becoming involved in the project is encouraged to reach out to Walter and his team at fiddleheadfarmstlh@gmail.com.  

It’s easy to see the decades of passion and vision behind Fiddlehead Farms. Pilot projects play an important role in showcasing the potential for agrivoltaics to truly make a difference in local communities. Whether it’s providing locally grown food to those in need or working with public officials to make positive changes in renewable energy policy, Fiddlehead Farms is poised to do it all for the Tallahassee area. “From the beginning, I’ve understood the importance of building all kinds of bridges. National, state, and local – even the friends that we’ve made here with the neighbors at the site,” Walter explains. Fiddlehead Farms is the next step in bringing those people together and strengthening the resiliency of the local community.  

All photos courtesy of Walter Liebrich. 

SCAPES Agrivoltaics Survey 

As agrivoltaics gain traction across the United States, research on barriers and opportunities for co-locating agriculture with solar is expanding. The SCAPES solar research project, led by the University of Illinois Urbana-Champaign, has received funding from the U.S. Department of Agriculture to study how to efficiently co-locate photovoltaic and agricultural systems in various biogeographical regions. As part of this research, the project team created a survey to better understand the strengths, weaknesses, opportunities, and threats of such co-location. 

Your voice matters! Please take 15 minutes to complete this survey. Your participation is greatly appreciated and will contribute to the success of our research. Your insights can impact future agrivoltaic considerations. We encourage all industry representatives to participate. 

Access the survey here: redcap.healthinstitute.illinois.edu/surveys/?s=4YFMYDLELE47C4EH   

Or use the QR code below: 

Solar Panel Shade and Potential Health Impacts

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AgriSolar News Roundup: Agrisolar Development, Aquavoltaics in Taiwan, Illinois Solar Grazing 

Agricultural Land Usually Remains in Agriculture After Solar and Wind Development  

“As [agrisolar] development has expanded, some communities have raised concerns about the local effects of solar and wind projects. USDA, Economic Research Service researchers recently studied how solar and wind development affects land cover near wind turbines and solar farms.  

Researchers examined the land cover in the three years prior to and following installation and found that cropland or pasture-rangeland usually stayed in the same land cover even after the addition of solar or wind development.” – ers.usda.govhttps://www.solarpowerworldonline.com/2024/07/avangrid-hires-5000-sheep-for-grazing-on-two-solar-projects-in-the-pacific-northwest/ 

WINAICO Develops New Solar Aquaculture Module 

“This year, the company will launch the AQUA salt-resistant double-glass module series, featuring double-layer coated glass with excellent density and light transmittance, POE encapsulation technology, highly waterproof seal performance of junction box, and apply a thicker oxidized film coating to shield the aluminum frame from corrosion.  

After more than 15 years of operation in Taiwan and the worldwide renewable energy market, WIN WIN Precision Technology has demonstrated expertise in customizing solar modules for island climates, its solar brand WINAICO holds exclusive patents for the wind-resistant and water drain valve designs.” – prnewswire.com 

Illinois Farmer Successfully Adapts to Solar Grazing 

“[Trent] Gerlach’s family had been raising corn, soybeans, and livestock since 1968, and like many farmers, they leased farmland in addition to working their own land. And when the owner of one of those leased parcels decided to work with Acciona Energia to help site its High Point wind and solar farm, Gerlach initially was not enthusiastic. 

‘The thought of taking productive farm ground out of production with solar panels was not, in my personal opinion, ideal,’ he said.  

But Gerlach was determined to make the best of the situation. 

Ultimately, that meant a win-win arrangement, where Acciona pays him to manage vegetation around the 100 MW array of solar panels that went online in early 2024. Gerlach does that with a herd of 500 sheep. 

‘It’s incredibly cost-effective — sheep don’t break down like a tractor; if a tractor blows a belt, you’ve lost a whole day of cutting,’ he said. ​‘These grasses grow wickedly fast, it’s that constant presence of the sheep that’s been super effective. It aligns with our sustainability goals.’” – canarymedia.com 

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Stakeholder Engagement in Agrisolar: Co-producing Optimal Outcomes

This publication intends to inspire critical thinking about the importance of social aspects in agrisolar projects. We highlight considerations related to cultural landscapes, social acceptance, and participatory planning and offer lessons learned from case studies and a Stakeholder Engagement Plan to empower project planners and stakeholders. The intended audience for this chapter includes project planners, community developers, solar developers, researchers, landowners, and community members. While broad, the intent is to provide background, context, and considerations for these different audiences and an approach to meaningful engagement.

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Crops Uniquely Suited to Growth in Agrivoltaic Settings  

Gary Paul Nabhan, PhD., Agroecologist, Borderlands Restoration Network 

When most Americans think of crop production, they tend to imagine crops growing in full sunlight to achieve their full potential for productivity. But over decades,there has always been crop production in shade habitats or constructed environments, as well. Indeed, much of the coffee and chocolate (cocoa) consumed as beverages has been grown under shade-bearing, nitrogen-fixing legume trees such as madrecacao  (Glyericidia sepia), a tropical tree with a dense and expansive canopy that protects understory crops from excessive heat and damaging radiation.  

Virtually all the food crops, forages, and medicinal herbs grown in North American agroforestry and alley-cropping systems are to some extent shade-tolerant. Many—like chile peppers—can comfortably tolerate a 35% to 50% reduction in photosynthetically active radiation (PAR) compared to open sunlight all day. They seldom suffer a yield reduction due to less sunlight in this range, especially from noon to 4 p.m. Iin fact, yields in some varieties are augmented, perhaps because a significant percentage of all arid, temperate, and tropical wild plants evolved to begin their lives under the shade of “nurse plants” and have evolved shade tolerance to varying degrees over millennia. More than 30,000 farmers in the U.S. were engaging in one or more types of agroforestry practices by 2017, when agrivoltaic practices first hit the American scene.  

Agrivoltaic pepper plants in Arizona. Photo: NCAT 

Benefits and Challenges of Solar and Crop Co-Location 

So, what kind of benefits do shade-grown crops receive, and what are the challenges of growing crops under any kind of shade, for both the trees and the solar panels? 

Benefits 

Let’s first look at the benefits. Shade reduces the amount of sunburn or sun scald that understory plants receive but particularly reduces the effects of damaging ultraviolet radiation. It also serves as a temperature buffer, reducing high summer temperatures by as much as 4°F to 6°F and keeping winter temperatures in crop canopies 2°F to 4°F warmer—in some cases, enough to avert premature freezes or to extend the frost-free growing season by as much as three weeks. With less direct sun, evaporation of water from the soil and transpiration from the leaves are reduced, and soil moisture stress may not be as severe.  

The flowers of crops abort less in cooler temperatures, and they also attract more pollinators. Plant desiccation is not only reduced, but the nitrogen content of the foliage also does not spike enough to trigger feeding frenzies by leaf-sucking or browsing insects. At the same time, the Brix levels—an indicator of how sweet and nutritious vegetables and herbs might be—is sustained at higher levels, adding to the value of the crop. 

Perhaps the ultimate advantage is that it buffers farmworkers managing or harvesting from severe heat stress and dehydration in hot summers, improving their harvesting efficiency and reducing their vulnerability to hazards and illness. In 2023 alone, 30,000 more outdoor workers in the U.S. succumbed to heat stress than in any other year in recorded history. Since hand-harvested crops are time-consuming, their harvesters are especially vulnerable. 

Thermal image showing farm worker under a solar panel with a body temperature of 80°F and an outdoor temperature over 100°F. Photo: NCAT 

Challenges   

The disadvantages of co-location are more obvious for some sun-loving plants than for others. If the canopy tree or solar panel “competes” for too much light, it will result in reductions in photosynthesis and yields, thereby impeding the growth of the underling. However, there may be more humidity retained in the under-panel microclimate that fosters fungal diseases and possibly leads to more plant damage from insects that thrive on the fungal environment. 

Crop height may be impeded, requiring more pruning or difficulty in harvesting. And of course, most mechanical harvesters of high stature are eliminated from use if panel are 5 meters (16.4 feet) or less in height. 

Lastly, the space under photovoltaic panels is economically and ecologically costly per square meter; the metal, copper wiring and glass or plastic fiber glazing in photovoltaic panels is burdened with considerable “embedded energy” within it, so each panel provides small but very expensive growing space (except when compared to high-tech, computerized greenhouses with air conditioning and movable benches.)  It is unlikely that growing grains or dry beans under photovoltaic arrays will ever be cost-effective. 

So, what is different and distinctive about the shaded growing spaces under photovoltaic panels? For one thing, these areas have solid or slotted covers, rather than being diffused and porous like most leafy canopies. Secondly, all constructed spaces in a photovoltaic array are of similar height and size, whereas the height and size(s) are highly variable in natural or semi-managed forests.  

In natural settings, “nurse trees” also offer much more than shade and temperature buffering to understory plants; they also offer mycorrhizal connections and soil fertility renewal. Some deep-rooted legume trees also pump and leak water and nutrients to other plants in their nurse plant guild that are too young to do this on their own 

The crops discussed here that are most suitable for agrivoltaics conditions are high-value cash crops or nutritionally dense fruits and vegetables for home or community consumption. These crops are more suitable for agrivoltaics conditions compared to grain or bean crops, for example. Medicinals and pharmafood crops would likely be a better fit for growing conditions that are produced from dual-use land environments. 

Agrivoltaic pepper plants in Arizona. Photo: AgriSolar Clearinghouse 

Considerations for Crop Selection 

It is important to consider what shape, size, and habit of crop plants might be most appropriate for agrivoltaics production over an extended period of time. When considering crops that will be well-suited for the conditions of an agrivoltaics site, it is important to consider the following points. 

Crop Characteristics: 

  • Vining or “bush” growth forms 
  • Sun-loving or shade-loving  
  • Height and width of fully grown plant 
  • Multiple harvests or single harvests required? 
  • Root depth 

If we were to design an “ideotype” best suited to the photovoltaic micro-environment, it would need to meet at least five of the following plant characteristics: 

  • Vertically-vining or “indeterminate” growth forms that make maximum use of the space under solar panels by being trellised or “stiffer” scandent plants that lean upon a trellis (such as dragon fruit and capers). Vining plants that spread out beyond the perimeters of the panels may have a cooling effect that increases photovoltaic energy production efficiency (his strategy assumes that the interspaces between panels are not being utilized in another way). 
  • Tolerate moderate (especially mid-day) shade, with interception or screening of photosynthetically active radiation (PAR) in the range from 35 to 50% of total daylight,  
  • Growth habit that will allow for harvesting of seed, fruit, flowers, floral buds, or leaves from waist high (1 meter or 3.28 feet) to shoulder-high (1.4 to 1.8 meters or 4.59 to 5.9 feet) above the ground to allow work by hand or mechanical harvesters. 
  • Can be harvested or “cut” multiple times per season, pruning them to stimulate subsequent regrowth and recutting within three to four weeks of the previous harvest. 
  • Be either deep-rooted or shallow-rhizomatous perennials with runners, or longer-lived seasonal annuals that can be uprooted after the last harvest to allow new transplants to go into the same space. 

Now that we’ve established the ideal architectural and behavioral criteria for selecting crop plants, here is a list of crops that meet three or more of these criteria. These lists emphasize high-value crop plants that have other adaptations to hot, dry conditions but may require partial shade or frequent cutting and harvesting. 

Berry vines and bushes with long, arching shoots that can be both vertically and horizontally trellised: currants, dewberries, gooseberries (Ribes spp.); brambleberries, blackberries, dewberries, and loganberries (Ribes spp.), grapes, including muscadines, musquats, scuppernongs, etc. (Vitis spp.) 

Arborescent and scandent cacti with high-value fruit: cochineal nopal (Opuntia cochiillifera) dragonfruit cacti, including  white-fleshed pitahaya (Selinicereus undulatus), red-fleshed pitahaya (Selenicereus costaricensis), and  yellow pitahaya (Selenicereus megalanthus); pitahaya agrias (Stenocereus gummosus, S. quereteroensis, and S. griseus), longer-lived seasonal annuals that can be pulled up after the last harvest to allow new transplants to go into the same space.      

Short-stature shrubs with copious production of fruits, buds, or berries over a long season: capers (Capparis spinosa); capulín sand cherries (Prunus salicifolia); chiltepín, chile del arbol, shishito, etc. (Capsicum annuum); Mexican hawthorn or tejocote (Crataegus mexicana); elderberry (Sambucus nigra); goji or wolfberry (Lycium barbarum, L. chinense, L. fremontii, and L. pallidum); Persian lime (Citrus x latifolia); key lime (Citrus aurantifolia); kumquat (Fortunella margarita and hybrids); jujube (Zizyphus jujba); guava (Psidium guajava); hibiscus or Jamaican sorrel (Hibiscus sabdardiff); or maypops and passion fruit (Passiflora spp.). 

Perennial culinary herbs that can tolerate (or increase production with) frequent, severe cuttings: Mexican oregano (Lippia berlandieri, L. graveolens), saffron (Crocus sativus), Mexican tarragon (Tagetes lucida), papaloquelite (Porophyllum ruderale) Sierra Madre oregano (Poliomentha madrensis), lavandin (Lavendula intermedia), Greek oregano (Origanum vulgare),  thyme (Thymus vulgaris), and lemongrass  (Cymbopogon citratus). 

Dwarf or drastically pruned trees with high-value fruit: dwarf varieties of figs (Ficus spp.), pomegranates (Punica granatum), cherries, including the Mahaleb cherry (Prunus mahaleb), olive (Olea europea), Sechuan peppers (Zanthoxylum armatum, Z. bungeanum, and Z. simulans), and Mediterranean sumac (Rhus coriaria). 

Long-season annual herbs or perennial pharmafoods (nutriceuticals) that can tolerate frequent cuttings: sweetleaf stevia (Stevia rebaudiana), holy basil or tulsi (Ocimum tenuiflorum), damiana (Turnera diffusa), saffron (Crocus sativus), wild Lebanese cucumber-melon (Cucumis melo, a parent of the popular beit-alpha greenhouse cucumber); and chia (Salvia hispanica). 

It is important to consider what horticultural design and density qualifies as having the optimal features required to grow in agrivoltaics conditions, for none of these proposed crops need to be grown in evenly spaced monoculture. For instance, the least sun-sensitive crop varieties can go on the periphery of the solar panels, preserving the core area for the most shade-tolerant varieties or species. 

A Speaker Discusses Agrivoltaics in Arizona. Photo: AgriSolar Clearinghouse 

Alternatively, taller woody perennials can be placed under the highest levels of the panels, with the shorter varieties or species reserved for the shortest area toward the “front” of the angled panel. However, new designs of photovoltaics have computerized solar trackers for mobile or reclinable units, so that may become an irrelevant consideration in the future. Another option is to grow indeterminate vine crops such as cucumbers or grapes on the periphery of the solar panel shadow. This might allow those crops to “crawl out,” and provide greenery that reduces ambient temperatures on the panel surface. This may increase daily energy production efficiency and extend the lifetime of the panel(s). 

A final consideration is that for extremely high-value crops like pharmafoods and pharmaceuticals, screening the sides of the growing space may reduce or halt predation by insects or vertebrate herbivores. The overall cost of construction and production in an agrivoltaic system would remain far less than that for most commercial greenhouses, but the agrivoltaic micro-climate and growing space would then be considered a “controlled environment.” 

When selecting crops that are uniquely suited to be grown in agrivoltaic settings, consider the guidance provided above. Ask questions related to the features of the solar panel design, including height, width, and other design features, as well as measurements. Then, consider the plant characteristics that are being considered for that site: height, width, water consumption, root depth, harvesting schedule, etc. Next, form a strategy from the characteristics you have identified for both the panels and the plants and make an informed decision about what will work best for that specific agrivoltaic site, as agrivoltaics conditions can vary from one site to another.

Case Study: Existing Solar as Farmland Access for Emerging Farmers 

By Rob Davis, Connexus Energy 

“Growing Farmers, Growing Foods” is the mission at Minnesota-based Big River Farms, a program of 501(c)3 nonprofit The Food Group. They recently won the North American Agrivoltaics Award for Best Solar Farm in 2024. Big River Farms teaches farmers to farm organically, sustainably, and regeneratively while also enhancing the level of understanding of the environmental impact that can result from properly implementing these types of farming practices. Specialty crop farmers are the backbone of our food system and are major contributors to local economies. However, land access is a major barrier for many emerging farmers, including farmers of color, in both rural and urban communities.  

Big River Farms Program Manager KaZoua Berry. Photo: AgriSolar Clearinghouse 

In 2022, the Minnesota Department of Agriculture established the nation’s first Emerging Farmers Office, with the intention of helping to remove barriers that emerging farmers face when getting started in farming. This includes new Americans and first-generation farmers who lack access to land or capital. Farmland access has been identified by the Emerging Farmers Office as the most common challenge for these farmers. 

Big River Farms works with farmers who are in constant need of land to farm on. Last year in Big River Farms’ incubator program, several farmers stated that they are ready to leave the incubator farm if they can buy land or access land elsewhere so that they can scale up independently. Expanding their program to solar sites will enable Big River Farms to build leadership and capacity in the immigrant community, diversify and enhance local food production, improve access for low-income households to healthy food, and build cultural bridges between emerging farmers and the larger community.   

Big River Farms, the Food Group, USDA Emerging Farmers Office, and Connexus Energy. Photo: AgriSolar Clearinghouse 

“With thoughtful planning and procurement, the community benefits of multi-acre solar projects can be numerous,” said Brian Ross, vice president of Renewable Energy for Great Plains Institute. “It’s important that we are stacking solutions to local food production and access into the clean energy transition.” 

With this project, the visibility of the dual-use solar will create new connections to the host communities for the solar arrays and build Big River Farms’ success and enhance its mission.  Association of the solar facilities with the Big River Farms’ equity goals will help resolve concerns about loss of agricultural capacity in communities hosting solar development and can contribute to accelerated deployment of solar sites on arable soils.  

“A quarter of an acre between rows can become an incredibly productive plot of land that right now isn’t necessarily in use,” said Sophia Lenarz-Coy, executive director of The Food Group. 

Abundant Crops Grown by Big River Farms Between Rows of Solar Panels. Photo: AgriSolar Clearinghouse 

The Solar Farmland Access for Emerging Farmers project seeks to increase land access to BIPOC and immigrant farmers through the utilization of spaces around solar farms, while concurrently documenting the safe and scalable practices that solar asset owners and insurers can implement as prerequisites of site utilization. Big River Farms, Great Plains Institute, US Solar, and Connexus have worked together to implement best practices from the National Renewable Energy Lab that have created replicable guidance for others seeking to collaborate and enable solar facility access for farming activities. 

Winners of the North American Agrivoltaics Award for Best Solar Farm in 2024: The Food Group, Big River Farms, US Solar, NREL, Great Plains Institute, and Connexus Energy. Photo: AgriSolar Clearinghouse 

Community opposition to multi-acre solar development is driven in part by communities misunderstanding the local benefits of agrivoltaics and thinking that farmland is being taken out of production. Developing solar does not mean farmland is being destroyed or taken out of production. LBNL’s recent research and NREL’s latest publications from the InSPIRE study show that utilities and solar developers need to maintain and improve what is known as “solar’s social license” in communities nationwide. To avoid the worst effects of climate change, more than 3 million additional acres of solar arrays need to be built by 2030.  

While incorporating agriculture into solar designs has been shown to increase public acceptance of solar, some approaches are looking at elevating solar panels 10 feet to grow commodity corn and continue status-quo farming approaches. However, hand-harvested crops commonly sold in farmers markets nationwide can readily be grown in abundance with existing solar facility designs, such as one or two panels on single-axis trackers and torque-tube height of six feet.  

Big River Farms Tomato Crop at US Solar Big Lake Array. Photo: AgriSolar Clearinghouse 

Through the Big River Farms program, farmers learn to scale up their food production while implementing sustainable and regenerative farming practices that improve water quality and usage. Having land access to get started as a specialty crop farmer fills a critical niche in helping address the larger challenges related to land ownership and sustainable, specialty farm operations. Building skills, network, and resources, especially in the agrivoltaics community, helps prepare specialty crop farmers for the next stages of their success. 

Moving Forward: Growing Farmers, Growing Crops 

Moving forward, Big River Farms and Great Plains Institute have been identifying barriers, challenges, and successes of utilizing solar spaces and gathering feedback from farmers, utilities, solar facility owners, and host communities. This project will build capacity and enhance the possibility of success for emerging farmers among immigrant and BIPOC farmers. It will also diversify local agricultural and food-production markets. Most importantly, it will help enhance the communities’ understanding of agrivoltaics systems and diminish the misunderstood concept that solar is taking over valuable agricultural lands.  

With these concepts and practices in place, it will help the organization achieve and sustain the mission of “Growing Farmers, Growing Foods.” Through education, the emerging farmers will succeed and prosper, and through sustainable and regenerative agrivoltaics farming practices, the foods will grow as well. 

Ecosystem Services of Habitat-Friendly Solar Energy 

Leroy J. Walston, Heidi Hartmann, Laura Fox, Michael Ricketts, Ben Campbell, and Indraneel Bhandari, Argonne National Laboratory  

This section highlights several types of agrivoltaic options related to ecosystem services that include siting considerations, ecological impacts of dual-use sites, construction methods and habitat restoration strategies. One type focuses on ecologically focused siting, construction, and vegetation management principles in an effort to make photovoltaic (PV) solar energy more ecologically compatible. This includes minimizing ecological impacts associated with siting and construction and improving the ecological value of the site through habitat enhancement. Given its ecological focus, this form of agrivoltaics design is often referred to as ecovoltaics (Sturchio and Knapp, 2023; Tölgyesi et al., 2023).  

The co-location of solar energy and habitat restoration (i.e., habitat-friendly solar‘ or solar-pollinator habitat) has become the most popular ecovoltaics strategy to safeguard biodiversity and improve the site’s ecosystem services output. Habitat-friendly solar designs typically focus on the planting and establishment of deep-rooted and regionally appropriate native grasses, wildflowers, and other non-invasive naturalized flowering plant species. The habitat created at these sites could support insect pollinators and other wildlife and improve other ecosystem services of the site (Figure 1).  

But what ecosystem service benefits might be realized at solar facilities managed for habitat? Agrivoltaics can broadly improve the output of all classes of ecosystem services (Figure 2). Conceptually, solar-pollinator habitat has the potential to improve the outputs of all classes of ecosystem services (Table 1).  

The pairing of solar energy and habitat enhancement sounds like a logical win-win for clean energy and biodiversity.  However, several factors can influence the feasibility and ecological effectiveness of solar-pollinator habitat, such as geography, seed availability and cost, previous land use, soil type, and solar size and design (e.g., PV panel height and spacing). Several scientific studies have been conducted in recent years to examine different solar-pollinator habitat configurations and management options. Two studies in particular are the Innovative Solar Practices Integrated with Rural Economies and Ecosystems (InSPIRE; openei.org/wiki/InSPIREopenei.org/wiki/InSPIRE) and Pollinator Habitat Aligned with Solar Energy (PHASE; rightofway.erc.uic.edu/phase). Both projects are funded by the U.S. Department of Energy (DOE) Solar Energy Technologies Office (SETO) and include a focus on the ecological and economic implications of solar-pollinator habitat. Results from these studies have shed light on which vegetation establishes at solar sites based on their unique management needs and the amount of time required for vegetation to establish and for biodiversity responses to be measured. These studies incorporate the research findings intoguidelines and toolkits to assist the site-specific selection of seed mixes and management strategies to optimize the performance of solar-pollinator habitat based on ecological and economic (budget) objectives.   

Figure 1. A) Illustration of the theoretical ecosystem services of solar-pollinator habitat. Compared to conventional groundcover, such as turfgrass, solar-pollinator habitat can provide higher-quality habitat for biodiversity. B) Example image of solar-pollinator habitat at a solar site in Minnesota. Images: Argonne National Laboratory 

Table 1. Potential Ecosystem Services of Solar-Pollinator Habitat. 

Ecosystem Service Benefit 
Biodiversity conservation (broadly linked to all ecosystem service classes) Solar-pollinator habitat can safeguard biodiversity by supporting a larger diversity of organisms and communities. This could benefit several ecosystem services, such as food production (provisioning), recreation (cultural), water conservation (regulating), and nutrient cycling (supporting) (Walston et al., 2021, 2022, 2024; Blaydes et al., 2024).  
Energy production  (provisioning service) Solar-pollinator vegetation can create favorable microclimates to improve PV panel performance (Choi et al., 2023).  
Food production (provisioning service) Solar-pollinator habitat can improve populations of insect pollinators and predators, which can benefit nearby agricultural production (Walston et al., 2024). 
Carbon sequestration and soil health (regulating services) The establishment of solar-pollinator habitat typically involves soil and vegetation management practices that allow for greater soil carbon sequestration over time, compared to other land uses (Walston et al., 2021).   
Stormwater and erosion control (regulating service) Deep-rooted solar-pollinator habitat can help stabilize soil and minimize runoff (Walston et al., 2021).  
Nutrient cycling and air quality (supporting services) Solar-pollinator habitat can improve nutrient cycling and air quality (Wratten et al. 2012; Agostini et al., 2021).  
Aesthetics and recreation (cultural services) Solar-pollinator habitat can improve human perception public acceptance of the solar site (Moore et al., 2021). 

What are best practices for establishing solar-pollinator habitat?  

There is growing science-based evidence on the ecological effectiveness of solar-pollinator habitat. Most of this research focuses on two main aspects: 1) vegetation establishment and management; and 2) biodiversity responses (Figure 2). One critical need for the solar industry has been assistance in selecting the seed mix design and vegetation management tools that would optimize the establishment of solar-pollinator habitat for a site’s specific physical characteristics (e.g., geographic region, soil type), PV site design (e.g., plant height restrictions), and budget. To help guide these decisions, the DOE PHASE project has produced a series of tools to inform solar-pollinator habitat planting implementation, seed selection, cost comparisons, and habitat assessment (Figure 3). 

Figure 3. Solar-pollinator habitat decision support toolkits developed through the DOE PHASE project. Source: rightofway.erc.uic.edu/phase-toolkits/rightofway.erc.uic.edu/phase-toolkits/.  

What do we know about the effectiveness of solar-pollinator habitat? 

This section highlights objectives and outcomes from field research projects funded by DOE to understand the ecosystem services of solar-pollinator habitat. Two case studies are presented: 1) potential biodiversity benefits of solar-pollinator habitat; and 2) potential benefits of solar-pollinator habitat for soil health. 

Case Study 1:  If You Build It, They Will Come 

A recent study from the DOE InSPIRE project examined the biodiversity responses for five years following the establishment of solar-pollinator habitat (Walston et al., 2024). The research was conducted at two Minnesota PV solar facilities owned and operated by Enel Green Power. The research team from Argonne National Laboratory, National Renewable Energy Laboratory, and Minnesota Native Landscapes conducted a longitudinal field study over five years (2018 to 2022) to understand how insect communities responded to newly established habitat on solar energy facilities in agricultural landscapes. Specifically, they investigated: 1) temporal changes in flowering plant abundance and diversity; 2) temporal changes in insect abundance and diversity; and 3)  pollination services of solar-pollinator habitat to nearby agricultural fields. The team found increases over time for all habitat and biodiversity metrics. For example, by 2022, the researchers observed a sevenfold increase in flowering plant species richness, and native abundance increased by over 20 times the numbers initially observed in 2018 (Figure 4). The research team also found positive effects of proximity to solar-pollinator habitat on bee visitation to nearby soybean (Glycine max) fields. Bee visitation to soybean flowers adjacent to solar-pollinator habitat were greater than bee visitation to soybean field interior and roadside soybean flowers (Figure 5). These observations highlight the relatively rapid (less than four years) insect community responses to solar-pollinator habitat. This study also demonstrates that, if properly sited and managed, solar-pollinator habitat can be a feasible way to safeguard biodiversity and increase food security in agricultural landscapes. Photos of solar-pollinator habitat insects visiting the on-site vegetation at these sites are shown in Figure 6. 

Figure 4. Observed and predicted measures of (A) flowering plant species richness and (B) native bee abundance recorded over time at two PV solar facilities planted with pollinator-friendly habitat in Minnesota. (Walston et al., 2024).  

Figure 5. Observed bee visitation to soybean flowers at different field locations in Minnesota. Different letters indicate statistically different groups at the p = 0.05 level (Walston et al., 2024).  

Figure 6. Solar-pollinator habitat and insects observed at solar facilities in Minnesota. Top: solar-pollinator habitat dominated by purple prairie clover and black-eyed Susan flowers, with a honeybee visiting a flower (inset). Bottom: solar-pollinator habitat dominated by yellow coneflower. Photos: Argonne National Laboratory 

Case Study 2:  Soil Health Benefits of Solar-Pollinator Habitat 

As PV solar energy sites become increasingly common, there is growing interest in identifying potential co-benefits, in addition to energy production, that could be provided using the same land area (Choi et al., 2023). These co-benefits include a variety of both economic and ecosystem services, many of which rely greatly on preserving, restoring, and/or maintaining a healthy soil environment, which is itself a valuable ecosystem service. Healthy soils are key to supporting and nurturing plant growth, and solar facilities offer a unique opportunity to improve soils that are either naturally low-quality or have been degraded from decades of agriculture. This can be accomplished through a variety of strategic planning initiatives and land management practices that focus on minimizing soil and vegetation disturbances and encouraging the establishment of ecologically friendly and sustainable ecosystems. By understanding the relationships and interactions that exist between plants and the soil environment, we can gain valuable insights into how to maximize land-use efficiency and increase sustainable land management practices over the large areas of land that will be required for utility-scale solar facility development needed to achieve the renewable energy goals of the United States by 2050.  

Just as healthy soil is necessary to support plant growth, plants can help improve soil health through various mechanisms (Figure 7). Soil health is characterized by a combination of physical, chemical, and biological properties, including bulk soil density, water infiltration and holding capacity, soil organic carbon and available nutrient contents, soil pH and cation exchange capacity, and microbial activity and diversity. Plant roots, especially those from deep-rooting perennial species (such as are found in many pollinator seed mixes), help reduce soil erosion and improve soil structure by providing a supportive network of course and fine roots that stabilize soil particles and aggregates while simultaneously improving water infiltration. Plants also supply organic matter, carbon, and other nutrients to the soil environment viasurface leaf litter, root exudates, and root litter. These organic matter inputs serve as nutrient pools for micro- and macro-organisms in the soil, and to increase soil water-holding capacity. Additionally, a portion of the carbon from plant organic matter inputs and microbial necromass will end up becoming associated with soil minerals to form mineral-associated organic matter (MAOM), which can have very long residence times in soil and serve as a carbon sink for atmospheric CO2 (Bai and Cotrufo, 2022). 

There are many ways that vegetation can be used at solar facility sites to provide additional benefits beyond increasing soil health. While there is much research that has shown the positive effects of vegetation on soil health, research that specifically addresses how soil health indicators are affected by land management practices at solar facilities is lacking. Given what is known, it is reasonable to expect that sustainable vegetation management at solar facilities will result in improved soil health over time. However, this is likely dependent on the degree of disturbance sustained during site construction, and possibly any number of other controlling factors, such as local climate, native vegetation, and/or soil type. For example, Choi et al. (2020) found that even after seven years of revegetation at a solar facility site in Colorado, carbon and nitrogen concentrations had not recovered to comparable levels of adjacent reference grasslands. The authors attributed this to the significant amount of topsoil removal and grading that occurred during site construction, which significantly disturbed and mixed the soil profile, resulting in severely reduced surface carbon and nitrogen levels. However, this study did not compare vegetated areas to non-vegetated areas within the site. Another study by Choi et al. (2023) did make this comparison at a site in Minnesota where topsoil removal and grading were avoided. The researchers found that revegetated areas had significantly more carbon, nitrogen, and other nutrients levels relative to the areas that were left bare and were ultimately similar to adjacent control plots (Figure 8). This disparity in results and lack of clear data presents a challenge to understanding soil health dynamics as it relates to land management practices at solar facilities.  

Fortunately, DOE SETO has sponsored a project whose sole focus is to gather soil data from solar facilities across a wide range of environments in the United States that can hopefully address this question. This project,  Ground-mounted Solar and Soil Ecosystem Services, is being led by Argonne National Laboratory and will provide standardized guidance on measuring and analyzing soil parameters central to soil health at solar facilities, and establish a national database of solar facility soil data that will hopefully shed light on how vegetation and land management at solar facilities can impact soil health over time.  

REFERENCES 

Agostini, A., M. Colauzzi, and S. Amaducci. 2021. Innovative agrivoltaic systems to produce sustainable energy: an economic and environmental assessment. Applied Energy. 281: 116102. 

Bai, Y. and M.F. Cotrufo. 2022. Grassland soil carbon sequestration: Current understanding, challenges, and solutions. Science. 377: 603–608.  

Blaydes, H., S.G. Potts, J.D. Whyatt, and A. Armstrong. 2024. On-site floral resources and surrounding landscape characteristics impact pollinator biodiversity at solar parks. Ecological Solutions and Evidence. 5: e12307. 

Choi, C.S., A.E. Cagle, J. Macknick, D.E. Bloom, J.S. Caplan, and S. Ravi. 2020. Effects of Revegetation on Soil Physical and Chemical Properties in Solar Photovoltaic Infrastructure. Frontiers in Environmental Science. 8: 140.  

Choi, C.S., J. Macknick, Y. Li, D. Bloom, J. McCall, and S. Ravi. 2023. Environmental Co‐Benefits of Maintaining Native Vegetation with Solar Photovoltaic Infrastructure. Earth’s Future. 11: e2023EF003542.  

Millenium Ecosystem Assessment (MEA). 2005. Ecosystems and Human Well-Being: Synthesis. Island Press, Washington, DC. 

Moore, S., H. Graff, C. Ouellet, S. Leslie, D. Olweean, and A. Wycoff. 2021. Developing Utility-Scale Solar Power in Michigan at the Agriculture-Energy Nexus. Stakeholder Perspectives, Pollinator Habitat, and Trade-offs. Report for the Institute for Public Policy and Social Research, Michigan State University. Available at ippsr.msu.edu/mappr/developing-utility-scale-solar-power-michigan-agriculture-energy-nexus. Accessed March 29, 2024. 

Sturchio, M.A. and A.K. Knapp. 2023. Ecovoltaic principles for a more sustainable, ecologically informed solar energy future. Nature Ecology & Evolution. 7: 1746-1749.  

Tölgyesi, C., Z. Bátori, J. Pascarella, et al. 2023. Ecovoltaics: framework and future research directions to reconcile land-based solar power development with ecosystem conservation. Biological Conservation. 285: 110242. 

Walston, L.J., Y. Li, H.M. Hartmann, J. Macknick, A. Hanson, C. Nootenboom, E. Lonsdorf, and J. Hellmann. 2021. Modeling the ecosystem services of native vegetation management practices at solar energy facilities in the Midwestern United States. Ecosystem Services. 47: 101227.  

Walston, L.J., T. Barley, I. Bhandari, B. Campbell, J. McCall, H.M. Hartmann, and A.G. Dolezal. 2022. Opportunities for agrivoltaic systems to achieve synergistic food-energy-environmental needs and address sustainability goals. Frontiers in Sustainable Food Systems. 16: 932018. 

Walston, L.J., H.M. Hartmann, L. Fox, J. Macknick, J. McCall, J. Janski, and L. Jenkins. 2024. If you build it, will they come? Insect community responses to habitat establishment at solar energy facilities in Minnesota, USA. Environmental Research Letters. 19: 014053.  

Wratten, S.D., M. Gillespie, A. Decourtye, E. Mader, and N. Desneux. 2012. Pollinator habitat enhancement: benefits to other ecosystem services. Agriculture, Ecosystems & Environment. 159: 112-122.  

Case Study: MNL Pollinator Friendly Conservation Grazing

MNL is an organization with a mission to “Heal the Earth,” through ecological restoration and native species landscaping. As the organization progressed, they established projects on solar sites, including conservation grazing and prioritizing native seeds and plants that provide pollinator benefits. Jake Janski, who’s been with MNL for over 20 years, is one of the leading players for MNL’s conservation grazing projects.  

Janski, Senior Ecologist and the Director of Strategic Planning with MNL, contributes to the organization’s pollinator-friendly solar projects. As he continued his work, he began to see more need for prairie management on solar sites than what mowers could successfully provide. In typical situations, prescribed burns are often used to create a disturbance event, further promoting the health of the prairie. However, prescribed burns could not be used at the solar sites, requiring an alternative method.  

Pollinator plants with solar. Photo: Jake Janski

After meeting a sheep farmer in 2017 who lived near one of MNL’s pollinator-friendly solar sites, MNL decided to try sheep grazing to reinvigorate vegetation and remove dead thatch. With the timing falling at the beginning of the solar grazing industry’s development, and with Minnesota not having a large sheep industry, Janski focused on using sheep solely to help with the pollinator habitat. In other words, they used sheep as another tool for vegetation management and chose not to place the larger focus on sheep production. Janski started seeing surprisingly good results from this method and has built up from there, expanding MNL’s solar grazing projects.  

MNL currently has about 60 Minnesota sites that incorporate solar grazing, with the average site being 20- to 00 acres and 2 to 10 kW. To date, they use 2,500 sheep, and they hope to expand their collaboration with other graziers to increase that number.  

Sheep grazing amongst flowers at a solar site
Sheep grazing amongst flowers at a solar site. Photo: AgriSolar Clearinghouse

The sheep graze the sites for two to four weeks to maintain the vegetation and account for stocking density. Since the sheep are used as a tool to promote pollinator habitat, there is some variability in animal management. There is an ideal time each year to graze the sites, but grazing at the same time each year would negatively interfere with the botanical species composition. To avoid this interference, MNL rotates the timing of grazing between years. 

Occasionally, the site will be grazed at a prime time for pollinators; however, Janski identified benefits for pollinators resulting from carefully managed solar grazing. For example, grazing allows for more gradual blooming periods. Staggering or delaying blooming extends the flowering season and will provide different food sources at different times. Grazing is also less aggressive, with plants rebounding faster than they would following a mowing event. This method promotes wildlife such as songbirds, rodents, and reptiles.  

Broadly speaking, Janski believes that grazing is far easier on all habitats. MNL has secured research funding to continue an on-going study investigating the grazing impacts on vegetation and plant communities at solar sites. The results from this study should further support the benefits of solar grazing.  

Monarch caterpillar and solar. Photo: Jake Janski

Despite the benefits that Janski has observed over time, there are some challenges associated with promoting a healthy trifecta of solar energy production, pollinator habitat, and animal welfare and production. One of his greatest challenges is getting the price points that are needed to build a robust program. He is competing with some low-cost mowing companies, while also dealing with overwintering costs and expenses of hauling water to sites. Janski and the team at MNL had to learn new information at a quick pace about animal health, especially on a landscape with variable conditions. Over time, they’ve been able to create better systems and know what to plan for.  

Bringing sheep on-site has made some aspects of site management easier. They are dealing with less equipment damage and healthier soil. The sheep have helped with weed control, and while they have not completely eliminated the need for spot spraying, they are creating healthier plants with more competition that should make weed infestations less likely over time.  

Janski shared that there was a time when an electric short started a fire on a site; however, the sheep removed the majority of the fire fuel load, resulting in a low-intensity fire that did not get hot enough to cause any damage to the panels. This is in direct contrast to mowing, which leaves a lot of material on the ground, creating a thick dense layer of fuel for fires. 

With such clear advantages, it is no wonder that solar grazing has helped ease the majority of public discomfort regarding solar. Janski recognizes that agrivoltaics (solar grazing and solar pollinator habitat) can be an important, multi-purpose system that benefits communities. He reports that every group that interacts with MNL wants to hear about solar grazing and that they enjoy seeing livestock on the land. This positive support is also helping to get policymakers on board. MNL is in discussions with the state of Minnesota about pollinator scorecards and updated policy-level incentives. Furthermore, the Minnesota Department of Agriculture is beginning to push solar grazing from an agricultural perspective, giving others the confidence to get behind it.  

With an increase in community support, Janski recommends creating and maintaining good partnerships with solar companies. The solar industry is a much faster moving market than agriculture in general, so forming these relationships can provide valuable updates on developments within the solar industry.  

This ties in with what Janski identified as MNL’s future goal: to get as far ahead of development as possible. They want to build sites that serve as a solar site and as a farm, with structures and paddocks pre-built. The sites will also promote pollinator habitat. To accomplish this, more market analysis is needed to show the importance of investing in agrivoltaic modifications at the start of site planning. Janski and MNL want to expand their reach to other states that are not yet as solar-heavy. This can be accomplished by serving as consultants to provide and share evidence and examples of sites that have seen beneficial progress during the development and operation of an agrivoltaic site to large audiences through marketing.