Tag Archive for: AgriSolar

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. 

Case Study: Caleb Scott, United Agrivoltaics

In 2012, Caleb Scott was working with solar developers to help seed and build sites. As he got more involved in the industry, his job expanded to help properly maintain these sites. Scott began mowing the solar sites but quickly realized it was a challenging task. Every site was different, with varying degrees of ground levelness, infrastructure spacing, and site vegetation-management requirements. Additionally, he had to be careful around the panels to avoid any damage from his equipment.  

When not working on-site, Scott, a seventh-generation farmer, took care of his flock of sheep. He realized that sheep would do a much better job at vegetation management than mowers and would get around easier. However, despite his experience in managing sheep and solar vegetation, it was difficult to convince the industry that sheep could be a valuable form of vegetation management. Scott began to work with Cornell University to collaborate with solar developers and use the University’s property to perform a demonstration site for solar grazing. This work gave him proof of concept, and he began grazing on solar sites in 2013.  

Photo of Caleb Scott

Caleb Scott of United Agrivoltaics at a solar site. Photo: Caleb Scott

After Scott received his first solar grazing contract, he was able to grow and strengthen his practice. In addition to being a founding board member of the American Solar Grazing Association, he also created United Agrivoltaics, one of the first and oldest agrivoltaic sheep-grazing firms in the U.S. United Agrivoltaics functions as a co-operative to promote expansion of the solar grazing industry and now has 103 sites in nine states. The organization uses Scott’s unique background to provide vegetation management with solar grazing, as well as consulting to implement agrivoltaics on solar projects.  

Scott and the other 80+ graziers involved with United Agrivoltaics pride themselves on creating a healthy, shared-use system. While their specialty is in solar grazing with sheep, they have also used chickens, turkeys, rabbits, and pigs to help maintain the site vegetation and increase the overall productivity of the site. Scott uses three different styles of grazing: mob, rotational, and low-impact sustained grazing. These management methods provide financial benefits in some cases and health benefits in others. Scott’s main priority when deciding which style to use depends on what is going to work best for the on-site forage content, as well as for his farm and animals.  

United Agrivoltaics recognizes the variability between sites and offers different tiers of service to help overcome this. This is a major benefit for asset owners as it allows them to form a contract and relationship with one party for all their site-management needs. Scott’s full management package includes services such as exterior perimeter mows, spraying herbicide as needed to control noxious or invasive species, and a clean-up mow to manage the vegetation the sheep did not eat.  

The flexibility of United Agrivoltaics’ services has helped the organization grow over time. They are currently grazing 15,000 sheep on more than 5,100 acres of solar sites, with a goal to double the number of sheep in the upcoming year. Scott himself is grazing 650 sheep on 200 acres, and this growth allowed solar grazing to become his full-time job. He and United Agrivoltaics have purchased and acquired other companies along the way to help them grow.  

As United Agrivoltaics continues to expand, they ensure that their services remain competitive with the costs of mechanical mowing. The grazing costs will vary depending on location and which rating scale the site owner chooses for their site. In an area with farm readiness considerations being met, fees can range from $380/acre for the full management package to more than $1,500/acre. Despite the large range in pricing, Scott recognizes that generalizing pricing would have a negative impact on the solar grazing industry due to the number of variables that determine contract pricing, such as site management requirements and feasibility for the grazier. 

Photo of three sheep on a solar site.

A trio of sheep on a solar site. Photo: American Solar Grazing Association

In addition to difficulties associated with selecting the correct pricing for a site, insurance can be an added challenge when solar grazing, as extra costs typically do not outweigh the value of the contract. One of Scott’s biggest initial challenges in the solar grazing industry was learning to manage the site as dictated by the contract. In some cases, he has had to change his vision of what he thinks the site should look like in order to meet the site owner’s needs. Farming motives can differ from solar operation motives and requires calculating the correct stocking densities. 

To help overcome these challenges, Scott’s advice is to reach out and talk to someone who has done it before to ask a lot of questions and educate yourself.  

“This industry requires a lot of teamwork, especially since the solar grazing industry is so young and we have so few sheep in the country. We need to help and support one another.” — Caleb Scott. 

Teaming up with individuals who have prior experience could allow for sharing things like insurance (costs), equipment, and other resources, which could mean saving additional money. It is also beneficial to discuss contracts with those who have experience. Scott recommends finding an organization, like ASGA, that helps farmers and joining them to learn and share ideas. 

This teamwork represents Scott’s overall goal for the solar grazing industry and United Agrivoltaics, which is to have as many sheep in the organization as are currently in the U.S. right now–over 3 million. He wants to accomplish this by expanding his company and farming group nationwide. By doing so, he hopes to see the sheep industry increase tenfold in the next 20 years, and he wants to be a part of that change. If this were to be accomplished, it would undoubtedly afford tremendous benefits for the solar-grazing industry. 

Case Study: Julie Bishop, Solar Sheep LLC

American Solar Grazing Association

Julie Bishop’s involvement in the solar grazing industry began with a snowball effect after receiving a herding dog. Once she acquired a herding dog for her grazing operation, she trained it in herding at her home, which progressed to owning ewes and lambs and operating a hobby sheep farm. Then, in 2013, Bishop discovered that there was a solar field just five miles from her New Jersey home. She soon realized that sheep could manage the vegetation just as well as the traditional gas-powered mowers that were used on the site. She then got to work to make her idea a reality.  

Bishop began the lengthy process of getting her sheep on that solar site. The land had originally been used as agricultural land but had been forfeited for the sole use of solar. Bishop and the solar company had to go to the municipality to ask for agriculture to be reinstated at that site. Additionally, they had to appear in front of the zoning and planning departments, send a letter to the community, and hold an open comment period in order to receive a variance. Finally, after nearly a year, Bishop was approved to move forward and was able to bring her sheep on-site for grazing.  

A sheep under solar panels. Photo: American Solar Grazing Association

Despite being one of the first solar graziers and not having connections to consult, Bishop was able to successfully manage her first site. News of this success spread, and additional companies reached out to Bishop to form new contracts. Since then, she has grazed in three states.  

Bishop says that solar grazing changed her life. Once a teacher, she is now a successful farmer who is only able to have her sheep operating at a larger capacity than she initially anticipated because of solar grazing. Her home farm is six acres, but the solar sites she grazes provide her the space she needs to expand her operation. She is now at the point of maximum capacity unless she changes her management style. 

Currently, Bishop puts dry ewes on the solar site in the spring, then adds and removes rams, and brings the ewes home at the end of the grazing season to lamb around November and December. The lambs are then weaned, and the dry ewes return to the solar site. To expand her operation, Bishop would instead start lambing on the solar site around April and May. While the lambing process requires a lot of initial work, it would lead to a less labor-intensive and lower input management for Bishop. Along with changing the way she grazes, Bishop is waiting for more solar sites that are in close proximity to her home farm.  

In addition to the challenges with expanding, Bishop identified some aspects of solar sites that can prove difficult when compared to traditional sheep management, such as site layout, trucking in water, and exterior perimeter fences that lack proper predator-proofing. After years of experience, Bishop has the knowledge and practice to overcome these challenges. For example, she worked with the solar developer at a site to build a bracket to prevent sheep from rubbing up against an emergency switch. The bracket keeps the equipment safe from the sheep but still provides easy access for a person as needed.  

Sheep moving through a solar site. Photo: AgriSolar Clearinghouse

The sites that Bishop grazes were not created with the intention of solar grazing, and this can lead to difficulties such as a poor line of sight when moving sheep. Bishop has been able to overcome this issue with the assistance of a well-trained herding dog. It is only fitting that the reason she became involved in the solar grazing industry is now one of her greatest assets.  

In her solar grazing work, Bishop has seen a shift in community perception. During the initial stages of solar development, there was pushback from communities that did not want agricultural land being used for solar development. Once Bishop brought the idea of solar grazing to the community, there was still some hesitation toward the new concept, and no one knew what to expect. Her success has allowed the community to view dual-use solar in a different way, and there is now a positive perception of solar grazing in her area.  

As one of the first solar graziers, Bishop is well equipped to provide advice to those looking to join the industry. She suggests teaming up with someone who has experience in solar grazing to learn the ins and outs of the practice. Additionally, patience is necessary. It is difficult to plan, and there are often periods of waiting for approvals and construction. Finally, she recommends carefully selecting sheep that will be a good fit for the management system. 

Bishop is a true example of the beneficial opportunities that solar grazing can provide. The additional land access granted to her through her contracts allowed her to not only expand her operation, but also to become an innovator in the expanding industry.  

AgriSolar News Roundup: Oregon Agrisolar, Illinois Agrisolar Testing, Solar Grazing Productivity 

5,000 Sheep to Graze Two Solar Sites in Oregon 

“Avangrid, member of the Iberdrola Group, has partnered with a fifth-generation Oregon rancher to graze sheep at two solar farms in Oregon and Washington and launched likely the largest ‘solar grazing’ operation in the region. Solar grazing is a vegetation management method used at solar energy facilities that uses grazing livestock, like sheep, instead of machinery. Sheep are effective at limiting the growth of weeds and vegetation, cutting down on wildfire risks while replacing the use of gas-powered machines.” – Solarpowerworldonline 

Alliant Energy Develops Agrivoltaic Research Project in Iowa 

“Researchers (in Illinois) are piloting how crops such as grains and soybeans used primarily to feed livestock grow with solar panels obstructing their full view of the sun. The counterintuitive practice is called agrivoltaics, a nascent industry that partners solar developers looking for large plots of land and farmers looking to make additional income. 

In just two years and despite physical constraints, initial findings suggest that the sorghum grain could be a promising crop to grow alongside solar panels. Branham said that so far it appears that combining sorghum with solar panels has resulted in a 59% increase in efficiency. And wildlife, including birds and bees, are flocking to the improved habitat.”- wbez 

Solar Grazers Say Grazing Sheep Under Solar Panels Improves Productivity 

“As a flock of about 2,000 sheep graze between rows of solar panels, grazier Tony Inder wonders what all the fuss is about. ‘I’m not going to suggest it’s everyone’s cup of tea,’ he says. ‘But as far as sheep grazing goes, solar is really good.’ 

On Inder’s New South Wales property, a solar farm has increased wool production. It is a symbiotic relationship that the director of the National Renewables in Agriculture Conference, Karin Stark, wants to see replicated across as many solar farms as possible as Australia’s energy grid transitions away from fossil fuels.” – The Guardian 

Expanding Agrivoltaics in Massachusetts

For several years, NCAT has been highlighting the benefits of agrivoltaics through the AgriSolar Clearinghouse project. And just as there are significant benefits to agrivoltaics, there are also barriers that keep more sites from being developed across the country, such as extra costs for site design, reduced energy production per acre, regulatory issues, and community pushback. In the current environment, it can take a passionate, mission-driven company to lead the way in changing how solar is integrated into agricultural systems. BlueWave is one such company.

BlueWave, a Boston-based solar development company, focuses on agrivoltaic solar projects, helping farmers design and integrate solar energy production on their farmland. One of the most prolific agrivoltaic developers in the country, BlueWave has recently added five more of these sites to their project portfolio, which totals over 91 acres and produces over 19 megawatts (MW) of electricity—enough to power more than 2,500 homes.

BlueWave’s latest series of installations began in 2023 and will be completed this year in four separate towns across Massachusetts. These systems were designed for adaptive dual-use purposes, meaning that a variety of agricultural enterprises can take place under the panels. Collectively, these solar installations represent many major agrivoltaic practices, including vegetable production, hay making, and grazing of sheep and cattle. Also, the forage blends used on the grazing sites include plants that are beneficial for pollinators.

(Caption: The increased height of the panels at this Dighton location allows the farmer to access the land with agricultural equipment. Photo: BlueWave)

One project in Dighton, Massachusetts, encompasses 21 fenced acres with 3.6 MW of installed solar panels that will produce an estimated 5,660 megawatt-hours of energy annually. Battery storage will contribute to the resilience of the electric grid by allowing the installation to provide clean energy to the grid when the sun isn’t shining. The panels here are raised 10 feet off the ground with 25 feet of space between the rows of panel post supports. This spacing will allow for agriculture equipment operation under the panels. BlueWave will be managing this site for the 2024 season, planting cover crops to improve soil health and fertility in preparation for vegetable production on the site. A small section of the land will be used to grow vegetables this year, though the final agricultural use will be determined by the farmer and will be adaptable over the years.

An hour away in the town of Douglas, a very similar solar installation will soon be completed and will be managed by a local farmer. Just over 20 acres was fenced to house 3.4 MW of power production. These panels are also raised and spaced to allow the farmer to maintain and harvest the hay fields below the panels.

A third, slightly smaller BlueWave agrivoltaic site was completed in Haverhill, a town in the far northeastern part of the state. Almost 15 acres were fenced in here with just over 2 MW of solar installed. Again, the panels were raised high enough to allow for grazing or tractor work on the fields

below the panels. A combination of vegetable production and livestock grazing by local farmers is the most likely use for this location.

(Caption: This site in Haverhill, Massachusetts, stands ready for grazing and vegetable production by local farmers. Photo: BlueWave)

On the other side of the state, a 2.4-MW system covering almost 12 acres was developed near the town of Palmer. This system, like the others, is designed for tractor work and large livestock grazing. The site will continue to be used by the landowner, Burgundy Brook Farm, for making hay and to graze cattle. As with the other sites that will see the use of farming equipment under the panels, the solar arrays are elevated, and the support posts are spaced to accommodate equipment and to allow enough sunlight to grow crops and forages under the panels.

A fifth BlueWave installation, also in Palmer, has a more conventional design with the panels closer to the ground and the panel rows closer together. But even here, the plan is for sheep grazing to manage the vegetation under the panels. Solar grazing like this can benefit farmers looking for land to graze their sheep. It can be less costly for the solar site management than hiring a land-management company or landscaper to do the job. And the generous amount of shade provided by the panels has multiple benefits for the sheep herd and the forage being grown. (See the recent ATTRA blog post “Throw Some Shade: Protecting Livestock from Heat Stress.”)

(Caption: Burgundy Brook Farm owns the land at this site in Palmer and will continue to graze cattle and make hay here. Photo: BlueWave)

In a further commitment to support agricultural production, BlueWave provided specialized farm equipment for use at several of these sites. For the site in Dighton, BlueWave has purchased a Carraro 80-hp tractor, a 3-shank chisel plow, a rotary harrow and seeder, a flail mower, and a 3-point to skid-steer adapter plus buckets. They anticipate purchasing an additional cultivating tractor, plastic mulch layer and water wheel transplanter for use on this site. Additionally, BlueWave purchased a John Deere 5425 and a Kuhn baler for Burgundy Brook Farm to use in their hay and grazing operation at the site in Palmer.

Agrivoltaics can help mitigate many of the challenging issues associated with the intense expansion of utility- scale solar development happening across the country. It can keep land in agricultural production while simultaneously producing valuable solar energy for the grid. The shade provided by the solar arrays can help retain soil moisture and improve the growth of many types of crops and forages with reduced irrigation. The shade also reduces heat stress and improves herd health when the land is used for grazing. The financial benefits for the farmer can help keep high-value land as farmland and facilitate the transfer of that land to the next generation. BlueWave understands these possibilities and is creating a space for them with on-the-ground agrivoltaic installations in Massachusetts.

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Energizing the Monarch Butterfly Migration

By Dan Salas, University of Illinois Chicago, Energy Resources Center – Sustainable Landscapes Program

The iconic monarch butterfly faces numerous threats in its migration across North America. Habitat loss, invasive species, pesticide use effects, disease, drought, and changing temperatures have collectively squeezed a vice of stressors on monarch butterfly populations. At the same time, the U.S. is undergoing a great energy transition towards renewable energy. Development of large utility-scale solar and other renewable energy projects is transforming landscapes in some parts of the country.

What will this energy transformation mean for pollinators like the monarch butterfly? That largely depends on the landscape change it brings. Fortunately, this changing landscape has given birth to a new form of land use: agrivoltaics. Agrivoltaics is the coupling of energy generation and agricultural production and can be represented by a mix of land uses that produce on-farm income, like grazing, crop production, or honeybee hive management. Agrivoltaics may also include ecovoltaics which often refers to establishing pollinator habitat. Such pollinator habitat can also benefit on-farm yields in surrounding croplands[1].

Can Solar Energize the Monarch Migration?

The Solar Futures Study[2] published in 2021 by the U.S. Department of Energy estimates that as much as 10.2 million acres may be required for solar development to achieve the 2050 renewable energy targets. Incorporating agrivoltaics into these changing lands can help diversify agricultural economies, reduce pesticide use, and increase pollinator habitat. But can these lands also help fuel the monarch migration?

The monarch butterfly population has undergone severe declines since the 1980s. This past winter (2023-2024) reported the second lowest populations for eastern monarch butterflies since they have been measured[3]. As noted, these declines are the result of a combination of factors, chief among them habitat loss and degradation. Loss of habitat reduces the butterflies’ resilience to other stressors, such as pesticide use, severe weather, and drought.

Pollinator Habitat Can be Risky Business

While greatly needed, creating pollinator habitat can be risky business for solar operators. But it’s not the potential for stinging insects that draws concern; statistically speaking, people have a better chance of dying from catastrophic storms than from a bee sting[6].

Rather, providing habitat to species at risk of extinction, while noble and beneficial, may unintentionally result in increased regulatory restrictions and operational limitations on a site operator. A species listed under the U.S. Endangered Species Act (or comparable tribal or state regulations) can add time, cost, and complexity to managing land and maintaining facilities over the life of a project.

Rewarding a Helping Hand

For this reason, the Rights-of-Way as Habitat Working Group, facilitated by the University of Illinois Chicago’s (UIC) Sustainable Landscapes Program, created a conservation agreement known as the Monarch CCAA (Candidate Conservation Agreement with Assurances). This agreement promotes upfront commitments to sustain or create habitat for the monarch butterfly. In exchange, companies receive regulatory assurances that no additional endangered species regulations will be required in recognition of their proactive conservation commitments.

This prospect has motivated solar developers and owners to consider enrolling in the program. Since its authorization in 2020, the program has resulted in over one million acres of monarch habitat commitments across the U.S. While being the largest voluntary conservation agreement in the U.S., it still requires more enrollment to achieve the levels of conservation needed for the butterfly. Previous studies have suggested that millions of acres of monarch habitat are required to achieve levels of conservation needed to avoid the threat of the migratory butterfly population’s extinction[7].

Biodiversity and wildlife habitat have been marginalized (literally) along field edges, fencerows, roadsides, and utility corridors. The Monarch CCAA offers energy and transportation land managers a chance to demonstrate commitments for monarch conservation, biodiversity net gain, and support for recovering other at-risk species.

Solar companies considering enrollment are encouraged to review resources available on the Monarch CCAA Toolkit[8], including enrollment guidance, webinars, and the application form. Contact UIC’s Sustainable Landscapes team with additional questions at dsalas4@uic.edu.

Learn More About the Monarch CCAA

The Rights-of-Way as Habitat Working Group at the University of Illinois-Chicago led a national collaborative effort to develop a voluntary conservation agreement to provide habitat for the monarch butterfly. The effort is unprecedented in terms of its cross-sector participation and geographic extent. The agreement spans the entire contiguous 48 states and is helping agencies and companies transform their vegetation management to benefit wildlife in need. Learn more at rightofway.erc.uic.edu/national-monarch-ccaa/.

About the University of Illinois Chicago Sustainable Landscapes Program

The University of Illinois Chicago (UIC) Energy Resources Center is home to the Sustainable Landscapes Program and the Rights-of-Way as Habitat Working Group, which convenes people at the intersection of biodiversity and infrastructure.

[1] Pollinator habitat near soybean fields was found to have a positive effect on insect visitation and soybean yield. See Levenson et al. 2022, doi.org/10.1016/j.agee.2022.107901, and Garibaldi et al. 2021, doi.org/10.1016/j.tree.2021.03.013.

[2] Read more at energy.gov/sites/default/files/2021-09/Solar%20Futures%20Study.pdf.

[3] Read more at worldwildlife.org/stories/eastern-migratory-monarch-butterfly-populations-decrease-by-59-in-2024.

[4] Check out our online map of native seed vendors and specialists at: rightofway.erc.uic.edu/resources/seed-expert-map/.

[5] See Walston et al. 2024, iopscience.iop.org/article/10.1088/1748-9326/ad0f72; Levenson et al. 2022, doi.org/10.1016/j.agee.2022.107901; and Garibaldi et al. 2021, doi.org/10.1016/j.tree.2021.03.013.

[6] From injuryfacts.nsc.org/all-injuries/preventable-death-overview/odds-of-dying/.

[7] See Thogmartin et al. 2017, https://iopscience.iop.org/article/10.1088/1748-9326/aa7637

[8] See rightofway.erc.uic.edu/working-group-access/monarchccaatoolkit.

Energizing the Monarch Migration 82024Download
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Harvesting the Sun, the Agrisolar Short Film, is Available Now!

Across the country, farmers, landowners, researchers, and solar companies are working together to harvest the sun twice: once with crops, honey, pollinators, and forage for grazing animals, and again with solar panels. This co-location of solar and agriculture is known as agrisolar or agrivoltaics. In Harvesting the Sun, the leading voices of the agrivoltaic movement come together to share their stories and shine a light on a climate solution that can increase farm profitability, save valuable water, improve the soil, provide shade for farm workers, develop valuable ecosystem services, and increase the resiliency of rural communities. 

If you would like to contribute to NCAT’s development of an Agrisolar Center to continue this work, contact us at agrisolar@ncat.org.

Case Study: Alaska Agrivoltaics

By Savannah Crichton, University of Alaska Fairbanks 

Southcentral Alaska is home to the state’s first agrivoltaics project, a study that aims to uncover the best practices for harvesting from both land and sun. The research team will monitor both farmed crops and native berry plants that grow between the rows of panels at an operational solar PV array.  The solar array is situated in the Matanuska-Susitna Valley, where the majority of Alaska’s farmland is located.  

The project, Agrivoltaics: Unlocking Mid-Market Solar in Rural Northern Climates, is a three-year project funded by the U.S. Department of Energy (DOE) Solar Energy Technologies Office (SETO).  

In 2023, solar developer and project partner Renewable IPP (RIPP) built an 8.5-megawatt solar array in Houston, Alaska, which was financed by diversified clean energy company, CleanCapital. This array is classified as mid-market solar–the middle ground between commercial solar projects and large-scale (>100MW+) utility solar. RIPP sells the electricity produced at this site to Matanuska Electric Association, the regional utility.  

Ribbon cutting at the solar array in Houston, Alaska. 

At northern latitudes, the sun hits the earth at a lower angle, causing solar panels to shade each other during sunrises and sunsets. To maximize energy production and avoid shading, solar developers may increase row spacing. With intentional design and wider rows, there’s ample land open between these rows for foraging or farming. 

The new Houston array is situated on a berry stand well known to local berry pickers. Drawing from their previous solar farm development experience, RIPP intentionally found a way to minimize the environmental impact of solar construction and increase community acceptance by maintaining as much of the native vegetation as possible. Some of the boreal species growing onsite include willow, alder, birch, moss, fireweed, labrador tea, bog blueberry, and lingonberry. The latter two are edible berry species that carry meaningful value to Alaska Native cultures and are prized by many in Alaska’s summer months.  

Instead of aggressive clearing methods that level land and remove certain ecological services, a low-mulching protocol was used to preserve topsoil and low-growing woody shrubs. Native low-growing species, like berries, can continue to grow and sequester carbon. If nutrient-rich soil is left intact, solar developers leave options open for the development of agrivoltaic applications to co-locate their array with food production.  

Blueberry bushes growing on the solar site. 

That’s exactly what a team of researchers at UAF from the Alaska Center for Energy and Power (ACEP) and the Institute of Agriculture, Natural Resources and Extension (IANRE) intend to study. UAF is one of six projects funded under the Foundational Agrivoltaic Research for Megawatt Scale (FARMS) program to conduct research on agrivoltaic opportunity for their communities.  

Principal Investigator Christopher Pike from ACEP and co-investigators Glenna Gannon and Jessie Young-Robertson pulled together an interdisciplinary team of engineers, farmers, and solar experts. The research team is joined by Alaska Pacific University (APU) Spring Creek Farm Manager and project co-investigator Benjamin Swimm,and RIPP founders Jenn Miller and Chris Colbert.  

Under the mission to bolster food and energy security, the team will measure both solar PV production and physiological health of crops over two growing seasons, develop a techno-economic analysis to guide future mid-market solar PV and agriculture projects, and connect with the community through educational programming.  

CEO and Manager of Renewable IPP Jenn Miller speaks to crowd at the solar farm. 

In the first few months of the project, the team compiled a diverse stakeholder pool of northern and Alaska-based landowners, farmers, utilities, solar developers, tribal organizations, academic researchers, and environmental agencies. Through individual outreach, team networks, and local events, over 200 people signed up to participate in a stakeholder needs assessment survey.  

The survey was distributed to evaluate stakeholder perspectives towards agrivoltaics in rural northern contexts. In addition to this data, the team will conduct a techno-economic analysis to understand the economic conditions in Alaska that may create hurdles or opportunities for those interested in developing agrivoltaic systems.  

The contributions from the stakeholder survey and follow-up interviews will inform the project’s agricultural research plans and economic analysis. Broadly, this input helps the team understand community acceptance and potential adoption of multi-use solar farms while also adding color to the picture of food and energy security in rural, northern regions.  

Preparation of the agricultural research plots at the Houston array will begin in summer 2024. The acidic silt loam soil will be amended with lime and compost in plot locations to make them more amenable to agricultural growth.  

With the soils tilled, planting will begin in summer 2025. A combination of popular commercial vegetables and animal forage crops will be planted and monitored throughout the growing season for their productivity both inside and outside the solar array.  

Crops at northern latitudes undergo unique challenges, like cool growing seasons and high solar radiation loads. Because of these unique conditions, some crops grown under solar PV arrays may experience improved productivity, while other crops that are usually productive in the rural north may not perform as well.  

Gannon, Young-Robertson, and ACEP research professional Savannah Crichton will coordinate the collection of plant physiology data of the agricultural crops, as well as the existing blueberry and lingonberry plants. Leaf-level physiological measurements of photosynthesis, transpiration, water use, and stress help define the dimensions of health in plants. These measurements will allow the team to understand the impact that fixed solar modules and increased shade have on the plants’ overall health, crop yield, and produce quality.

Close-up of the blueberries growing on-site.

Likewise, Pike and ACEP research engineer Henry Toal will monitor the solar power production and gauge the impact of farming activities on the array’s operation and maintenance costs. Weaving together qualitative, economic, physiological, and electrical data will allow the team to evaluate the feasibility of agrivoltaic systems in the north.  

Rural households in Alaska spend nearly 27% of their annual income on energy expenses, and around 95% of Alaska’s non-subsistence food supply is imported. If an agrivoltaic model works in Alaska, it could be a major breakthrough for increasing food and energy security in the state. The impacts of this research have significant potential value, not just for solar developers and farmers, but for entire communities.  

If you’d like to learn more about the project, visit our website or email Savannah at sgcrichton@alaska.edu.  

The research is based upon work supported by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) under the Solar Energy Technologies Office (SETO) Award # DE-EE0010442. 

AgriSolar News Roundup: Stable Returns in Agrisolar, Agrisolar Market Forecast, Agrisolar Increase in US 

Farmers Across America Chase Stable Returns 

“Farmers are increasingly embracing solar as a buffer against volatile crop prices and rising expenses. Their incomes are heading for a 26% slide this year, the biggest drop since 2006, as cash receipts for corn, soy and sugar cane are expected to drop by double-digit percentages.  

The shift is a big part of the renewables push in the US: The American Farmland Trust estimates that 83% of expected future solar development will take place on agricultural soil.” – bloomberg.com 

Agrisolar Market Forecast to be Worth $10.64 Billion by 2033 

“The Brainy Insights estimates that the USD 2.98 billion Agrivoltaics market will reach USD 10.64 billion by 2033. Increased government initiatives to boost R&D in agrivoltaics is one major factor that may create lucrative opportunities for agrivoltaics devices in the market. Governments across the globe have undergone tremendous initiatives to boost investments and increase subsidies in the market. To achieve net-zero carbon emissions the government across the globe is undergoing a renewable fuel-based economy.” – finance.yahoo.com 

US Farms with Solar Have Tripled Since 2013 

“Solar panels are gaining popularity across U.S. fields. In fact, there are now three times as many farms with solar installations compared to 2012. 

In 2012, a little more than 36,000 U.S. farms had them installed. By 2017, that number had jumped to more than 90,000. In 2022, it shot up to nearly 120,000. 

Successful Farming found some producers were being offered as much as $1,000 per acre to lease land for solar. While crops can net that much, the panels do not require any input costs like seed and fertilizer.” – rfdtv.com