Tag Archive for: Solar Grazing

Lego Solar Farm Prize for Best Photo Taken During the Follow the Sun Tour

AgriSolar Clearinghouse partner Rob Davis has generously offered a full Solar Farm Lego set as a prize for the winner of the competition for best photo taken at one of the Follow the Sun tour field trips.

This set is priceless and can not be purchased.  If you support the idea of a real-life Lego set being commercially available, vote here: LEGO IDEAS – Solar Farm.  For a great background on the kit, see this NREL blog.

Please post your Follow the Sun photos to our forum here, or tag us on social media by using the hashtag #AgriSolar.

Solar Farm Lego Set. Photo: Rob Davis

The Follow the Sun Tour launched in Arizona, at Biosphere 2 and the Manzo Elementary agrivoltaic research site, and it was a great educational, inspirational, and networking event.  Next up, we will travel to Minnesota on August 4 to tour Enel North America’s Lake Pulaski agrisolar site, US Solar’s Big Lake agrisolar site, and Connexus Energy’s agrisolar site in Ramsey. We’ll end the day on a sweet note with an Enel-sponsored Solar Farm to Table™ event featuring foods grown or pollinated at agrisolar sites.  Get your free tickets here: Events – AgriSolar Clearinghouse.

The next week, we’ll travel to Massachusetts for a tour of the University of Massachusetts South Deerfield agrisolar research site and then  the Million Little Sunbeams solar and hay farm, capping off the day at Knowlton Farms. Get your free tickets here: Events – AgriSolar Clearinghouse

In September, we will join forces with Jack’s Solar Garden, Sprout City Farms, and our partners at NREL and University of Arizona to tour Jack’s Solar Garden during its annual Night on the Farm.  Stay tuned for details.

Over the next year, we’re planning more field trips to central California, Texas, Oregon, Virginia, Idaho, New York, and many more sites.  If you have a site you’d like to highlight with an AgriSolar Clearinghouse fieldtrip, we’d love to hear from you.  We’re looking forward to seeing you on the road!

Solar Sheep – an example of multifunctional land use

By Emma Kampherbeek

Land is limited. Agriculture, electricity production, housing, nature, etc. all compete for the same plot of land. In some areas more than in others, but the competition is everywhere. On top of that, greenhouse gas emissions keep increasing and the global temperature keeps rising, leading to more frequent natural disasters and parts of the earth becoming uninhabitable. We shouldn’t only focus on stopping the global temperature from rising, but also on climate change adaptation and multifunctional land use now that ‘good’ land is getting scarcer.

It makes sense to have at least dual land use, but preferably use land for three, four or even more purposes. Agriculture and electricity production are a really good fit that can create win-win situations. That’s why I researched what I like to call ‘Solar Sheep’ – sheep that perform vegetation management on solar farms.

A lot of research is currently being done on the impacts of solar farms on soil health and biodiversity of flora and fauna. But what about sheep? Sheep are very effective grazers, which means that they are perfect for vegetation management on solar farms. Unlike goats, sheep don’t jump on the panels and don’t chew the wires. Unlike cattle, they are not heavy and large, which means that they can easily graze under the panels. They are also great with different types of terrain, like steep, rocky hills, which are hard to navigate for (robotic) mowers. These are a few of the advantages of sheep for solar farm owners.

Gold Tree Solar Farm Sheep Grazing. Photo: Emma Kampherbeek

How about advantages for the sheep? Is it also a positive experience for them to graze under solar panels? As many farmers who use their sheep for vegetation management on solar farms can tell you, sheep really don’t seem to mind grazing under and between the solar panels. This is also what my research showed, which was conducted on Gold Tree Solar Farm in San Luis Obispo, CA, in January 2021. Sheep on the solar farm grazed more than sheep in the natural rangeland without solar panels (see Figure 1). The solar panels provide shade and protection to the sheep. This prevents them from experiencing heat stress and protects them from harsh weather conditions, which will happen more frequently in the face of climate change. I live in the Netherlands, so heat stress didn’t use to be a big issue here, but in the last decade cases and mortality of heat stress have increased significantly.

Figure 1 Bar graphs showing the mean (± SEM) of the total percentage of time spent grazing during the Main study over the total period of sixteen days of both treatment groups (NR & S) and both management types (R & IR).
* P < 0.0001, ** P = 0.0015, *** P = 0.031. (S = Solar; NR = Native Rangeland; R = Rotational; IR = Intensive Rotational).

The article is now under peer review but will hopefully be published later this year in the Journal of Applied Animal Behaviour Science as an open-access article.

Case Study: Solar Grazing at Susquehanna University

Some institutions of higher learning are reducing fossil fuel use by investing in solar panel installations on campus. However, most of them don’t use grazing sheep to manage the grassland under their panels. In 2019, Susquehanna University (SU) in Selinsgrove, Pennsylvania put into service a 14-acre, 3-megawatt solar system, located on its Center for Environmental Education and Research property. The school leases a flock of sheep from Owens Farm, located near the University in Sunbury, Pennsylvania, to act as natural lawn mowers for the fenced solar array.

This solar project is a partnership between the university and WGL Energy Systems. WGL owns and operates the facility under a 25-year power purchase agreement (PPA), and Susquehanna purchases electricity back from WGL. Commercial PPAs such as this allow organizations like SU to buy power directly from the generating company and not an electric utility. This arrangement gives the generation company an incentive to invest in renewable generation installations, which is a key part of financing projects like this. A second company, SCG Power, provided design and construction services to the project.

Katahdin sheep grazing the grass aisles between solar panels. Photo: Susquehanna University

Caroline Owens of Owens Farm said that she dedicates 40 of her farm’s Katahdin sheep to fulfill the solar grazing contract with the university. Owens raises more than 100 sheep and works with the university to provide managed grazing under the panels throughout the pasture season each year. Owens is a member of the American Solar Grazing Association (ASGA), an organization promoting best practices for grazing livestock under solar panels. According to ASGA, solar grazing is one of the most common and effective ways to combine solar and agriculture, and sheep are among the best livestock choices for the task.

Sheep grazing in solar fields utilize the shade provided by the panels. Photo: Susquehanna University

Though Owens Farm is paid by Susquehanna University for the grazing services provided, the arrangement is mutually beneficial: Owens Farm gets extra income and access to more grazing land, and the university gets well managed vegetation, which is essential for optimal performance of the solar array. Both Owens Farm and the university are happy for the opportunity to show a working example of their shared commitment to reducing fossil fuel use. The partnership has another benefit, too, in the form of a learning opportunity each year for a Susquehanna University student who gets to be a shepherd for a season and help manage the flock.

Case Study: EDF Renewables Amprior Site Agrisolar

Arnprior Solar site in fall and winter
All photos courtesy of EDF Renewables

EDF Renewables (EDFR) has dedicated its efforts for over 35 years to create a sustainable energy economy.  They have developed nearly 24 GW and continue to manage nearly 13 GW of wind and solar energy generating projects in North America.  Among these renewable energy sites is the Arnprior solar project located in Ottawa, Ontario, Canada. Arnprior is a 23.4MW array that sits on nearly 180 acres and provides enough power to meet the peak energy demands of around 7000 homes. When completed in 2009 the array doubled the solar PV energy generating capacity of the entire country of Canada. Six years after construction was completed, one of the landowners, Diane Egan, expressed an interest to EDFR on how the site would be returned to agricultural land after decommissioning.

Beehives at Arnprior

In 2015, the asset management team at EDFR started by curtailing the use of herbicides and pesticides, but they didn’t stop there on biodiverse and environmental projects at the site. By 2016, with all of the news coverage of decreasing bee populations, the team reached out to Marianne and Matt Gee of Gees Bees Honey Company to install hives at Arnprior. They started by installing two hives at the site that produced nearly 100 jars of honey per year. In 2022, there are now five hives that produce over 300 jars of honey annually.

Monarch larvae at Arnprior

In July of 2017, EDFR was awarded by the Government of Canada to provide a complete habitat for the monarch butterfly. The Arnprior site was the first of any solar project in Canada to be awarded by the Habitat Stewardship Program for Species at Risk (HSP SAR). EDFR formed a partnership with Victoria Wojcik and Kathleen Law of Pollinator Partnership, the worlds largest pollinator focused non-profit organization, to begin planting native wild flowers and milkweed. After a targeted seeding plan and professional training program, milkweed began to grow and thrive. Milkweed is the exclusive host plant that monarch larvae feed on. Within only one month of the award the larvae and iconic butterflies began to appear.

Chris Moore, Lyndsey Smith, and Bunny of Shady Creek Lamb Company

Furthermore in 2017, the Arnprior site launched a pilot program to use sheep grazing for vegetation management. Chris Moore and partner Lyndsey Smith of Shady Creek Lamb Company brought 50 ewes to manage the growth of the vegetation around the panels. EDFR found that not only did sheep grazing the vegetation under the solar panels align with vegetation management needs, but it also provided a mutually beneficial and effective solution for local sheep farmers interested in expanding their flock without having to buy or rent additional land.  Shady Creek Lamb Co. now had an opportunity to be paid for grazing.  Now in 2022, after lambing on-site, 500 sheep can be seen roaming around from spring to fall.  Shady Creek Lamb Co. has benefitted from dual-use by having access to additional land allowing them to expand their flock, grow their business and produce grass fed free range lamb and fiber for local markets.

Overall, the implementation of apiaries, monarch habitats and sheep grazing at the Arnprior site help to conserve farmland and promote healthy ecosystem biodiversity.  The site continues to maintain and expand the biodiversity projects exemplifying dual-use/agrivoltaics as a win-win solution for EDFR, the solar and agricultural communities and businesses being supplied by the honey, lamb, wool and electricity.

An ewe enjoys the shade of the solar array.
The flock is unaffected by the solar array

Case Study: Cannon Valley Graziers

Cannon Valley Graziers is a vegetation-management company based in Southeastern Minnesota. Since 2018, Arlo Hark and Josephine Trople have been using their flock of sheep to manage vegetation in a variety of environments, working closely with customers to meet their management goals. Cannon Valley Graziers provides vegetation-management services for solar developers throughout southern Minnesota. The vegetation on community and utility solar sites is traditionally mowed multiple times per year, incurring high operations/maintenance costs. By applying adaptive-grazing strategies on these solar sites, Cannon Valley Graziers can reduce the annual maintenance costs for developers, while also having a positive impact on the soil health and water quality of southern Minnesota. 

Photo Courtesy of Cannon Valley Graziers

The principles of adaptive grazing are well-suited for vegetation management. By mob grazing—introducing a large number of sheep into a small area for a short amount of time—Hark is able to deploy his flock with surgical precision to meet the needs of each site. After the desired objectives are met, he moves the flock to the next site. Meanwhile, the vegetation is allowed to recover, strengthen its root systems, and grow more resilient. Hark says these root systems are key for soil regeneration and water quality. Deeper roots build organic matter and allow for the transfer of minerals deeper into the soil. Strong root systems also improve the soil’s ability to store and maintain water, which reduces soil erosion and chemical runoff into nearby waterways. 

Photo Courtesy of Cannon Valley Graziers

Growing a sheep-powered vegetation-management company is not without challenges. Large flocks require large trucks and trailers to move from site to site. In addition, most sites do not have water, so water must be supplied by the grazier. But to Hark, the effort is worth it. “It makes sense to stack benefits on these sites,” he explains. “We are providing a top-notch service to our customers, improving soil and water quality, and providing meat and fiber to our community. It just makes sense.”

Characterizing the Ecological Implications of Utility-Scale Solar Energy on Fallowed Farmlands

Written By: Amanda Gersoff (M.Sc. student), Dr. Seeta Sistla

Natural Resources Management and Environmental Sciences Department, Cal Poly, San Luis Obispo

Our team is studying the ecological aspects of utility-scale solar arrays set on former agricultural land whose understory is maintained by sheep grazing. By gaining a better understanding of the ecological implications associated with panel shading coupled with grazing by sheep, we hope to develop insights into agrivoltaic development that can maximize positive environmental effects while reducing negative externalities. We are currently focusing on two utility-scale solar energy sites located in San Luis Obispo County, California. At these sites, we conduct weekly monitoring to measure surface microclimatic features, soil nutrient cycling processes, and plant community composition.

Collecting soil cores at Topaz Solar Farm. Photo: Amanda Gersoff
Collecting aboveground biomass samples at Topaz Solar Farm. Photo: Amanda Gersoff

We hypothesized that the novel shading caused by the arrays will affect plant and soil dynamics, including decomposition, biomass production, plant moisture content, the timing of plant community events (like flowering duration and time to senescence) and plant nutrient content. Our work has suggested that placing arrays in arid grazing landscapes that are emblematic of the western U.S. can confer synergistic benefits for the plant community and their grazers. For example, our work has found that the plant mass beneath the array rows has high water content, greater nitrogen content (correlated with higher soil plant-available nitrogen), and lower non-digestible fiber content than areas that are grazed but outside the arrays’ direct shading influence. We are currently tracking phenological patterns of greenness and flowering time/duration in the array, to better understand if the traits we are observing correlate with an extension of the growing season for the community with the array’s shading area.

Over the next year, we will continue monitoring to gain a more comprehensive understanding of how exactly spatial heterogeneity created by panel shading influences ecological systems. At both sites, the practice of solar grazing, in which sheep are used to maintain vegetation under solar panels, has been implemented. By combining agricultural and renewable energy production, also known as agrivoltaics, multiple benefits can be realized. Utilizing rotational grazing by sheep is beneficial because it can reduce the costs of mowing and maintenance, support local shepherds, cultivate biodiversity, cycle nutrients into the soil, and decrease the risk of sparks igniting dried grasses. As utility-scale solar energy grows, it is important to look to dual-use solar for increasing efficiency and maximizing environmental benefits.

Rotational grazing by sheep at Goldtree Solar Farm. Photo: Amanda Gersoff
Patterns of phenological differences  vegetation due to shading at Topaz Solar Farm.  Photo: Amanda Gersoff
Owl’s clover (Castilleja exserta): An annual native wildflower common in the rows adjacent to panels at Topaz solar Farm. Photo: Amanda Gersoff

American Solar Grazing Association, AgriSolar Clearinghouse Partner on Webinar Teatime Series

The AgriSolar Clearinghouse is partnering with the American Solar Grazing Association to run a series of joint educational agrivoltaic webinar presentations, known as Teatimes. These events are free and open to the public, and recordings will be broadcast on the AgriSolar Media hub if you can’t make the live event. 

The series will start April 21, with the presentation Leasing for Community and Grid-Scale Solar – Key Considerations While Negotiating, by Tom Murphy, the Director of Penn State’s Marcellus Center for Outreach and Research (MCOR). To join the webinar, use this link, meeting ID, and passcode:

Zoom link: https://us02web.zoom.us/j/81562414717?pwd=b2xnQ3hCQk1nMkh3aGM5dzRHS2JIZz09
Meeting ID: 815 6241 4717
Passcode: 414544

ASGA is  founded by farmers for farmers and solar professionals. They swap stories, best practices, and good ideas about solar grazing. We are excited to bring their valuable experience and expertise to the AgriSolar Clearinghouse network and hope this partnership will help foster connections, promote best practices, and provide support for solar graziers around the country.

Check out our events page for future dates, topics, and sign-up information.

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MN Research Shows Solar Grazing Improves Soil Quality

Solar energy is the fastest growing renewable energy source. It is predicted that 20-29% of global power will be sourced by solar by 2100. Solar energy requires larger land footprints and long-term commitments. Vegetation left under solar panels reduces soil degradation and opens up the potential for solar grazing as a dual income for farmers and vegetation management for solar utilities. Research conducted on multiple solar sites in Minnesota reveal there can be meaningful forage in 45% shade and 80% shade from solar panels. Furthermore, grazing sheep under solar panels produces both a higher content of carbon and nitrogen in the soil. Managed episodic grazing can be used as a strategy for carbon sequestration and vegetation management. Soil properties show an overall improvement and benefits depending on soil properties. Future work must be done to measure the long term soil carbon and hydrological properties.

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Nutrient Cycling in Pastures

This publication looks at the pathways and drivers that move nutrients into, out of, and within pasture systems. It attempts to provide a clear, holistic understanding of how nutrients cycle through pastures and what the producer can do to enhance the processes to create productive, regenerative, and resilient farm and ranch systems.

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Agrisolar Best Practices Guidelines

Agrisolar is a rapidly expanding sector with incredible potential. It brings together two major sectors of our society and economy: agriculture and energy. The goal of this guide is to draw on past experiences, to take stock of “what works” and “what doesn’t,” in order to advise local and international actors on successfully developing Agrisolar. This first edition of the SolarPower Europe Agrisolar Best Practices Guidelines takes a step in joining forces with agricultural stakeholders to better understand how the solar and agricultural sector can work more closely together, enhancing synergies to advance the energy and climate transition. Every Agrisolar project is unique as it must be adapted to the local agronomical, environmental, and socioeconomic conditions of the project site, and adapted to the needs of farmers and other relevant stakeholders. The most important element to ensure that Agrisolar projects perform effectively as agricultural and photovoltaic projects is to begin by clearly defining a Sustainable Agriculture Concept. Defining a Sustainable Agriculture Concept means assessing how to improve the sustainability of the agricultural practices carried out on site, assessing whether the project can provide local ecosystem services, assessing how it can be best integrated within the local social and economic setting, all while generating clean electricity. Following best practices throughout all 19 areas identified in these guidelines will ensure Agrisolar projects deliver tangible benefits, as planned in the Sustainable Agriculture Concept.

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