Tag Archive for: Solar Grazing

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.”

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

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.

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.

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.

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.

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.

Grasslands and croplands located in temperate agro-ecologies are ranked to be the best places to install solar panels for maximum energy production. Therefore, agrivoltaic systems (agricultural production under solar panels) are designed to mutually benefit solar energy and agricultural production in the same location for dual-use of land. However, both livestock farmers and energy companies require information for the application of efficient livestock management practices under solar panels. Therefore, this study was conducted to compare lamb growth and pasture production under solar panels and in open pastures in Corvallis, Oregon in spring 2019 and 2020. Averaged across the grazing periods, weaned Polypay lambs grew at 120 and 119 g/head/d under solar panels and open pastures, respectively in spring 2019 (P=0.90). Although a higher stocking density (36.6 lambs/ha) at the pastures under solar panels was maintained than open pastures (30 lambs/ha) in the late spring period, the liveweight production between grazing under solar panels (1.5 kg ha/d) and open pastures (1.3 kg ha/d) were comparable (P=0.67). Similarly, lambs liveweight gains and liveweight productions were comparable in both pasture types (all P>0.05). The daily water consumption of the lambs in spring 2019 were similar during early spring, but lambs in open pastures consumed 0.72 l/head/d more water than those grazed under solar panels in the late spring period (P<0.01). However, no difference was observed in water intake of the lambs in spring 2020 (P=0.42) The preliminary results from our grazing study indicated that grazing under solar panels can maintain higher carrying capacity of pasture toward summer, and land productivity could be increased up to 200% through combining sheep grazing and solar energy production on the same land. More importantly, solar panels may provide a more animal welfare friendly environment for the grazing livestock as they provide shelter from sun and wind.

Despite the mature and promising potential for solar photovoltaic (PV) technology to retrench global reliance on fossil fuels, large-scale PV development is experiencing complex challenges, including land use conflict and — as the scale of solar has increased — social resistance, which has previously been more commonly associated with large-scale wind farms. Growth in large-scale PV development can create land use disputes, especially in instances of competition between land for agriculture versus energy production. This history and growing concern over land use highlights the challenge of meeting the soaring demands for solar power while conserving rural and agricultural lands. It is posited that the impact of solar development on land will be diminished by siting PV in a manner that is compatible with multiple uses, suggesting changes in conventional practices will be necessary. The specific intent of this study was to draw insight about solar development from participant experience, and responses indicate that the most considerable opportunities and barriers center on social acceptance and public perception issues. Perspectives about the opportunities and barriers to agrivoltaic development were captured via interviews with solar industry professionals, and inductive analysis revealed that interviewees were most focused on opportunities and barriers that correspond with Wüstenhagen et al.’s three dimensions of social acceptance: market, community, and socio-political factors. The social acceptance of renewable energy is shaped by a complex interplay among market, community, and socio-political factors. While this framework is constructive for understanding the varying dimensions of social acceptance, Devine-Wright et al. assert that it is weak in terms of the relationships between dimensions, suggesting that further research should apply a holistic approach for discerning the interdependence among factors shaping social acceptance of renewable energy. The purpose of this study is therefore to explore the perceptions of industry professionals in the U.S. and consider the implications of the identified opportunities and barriers from a social science perspective. To address global demands for both food and energy, the relationship between critical land uses must become complementary rather than competitive. Because social acceptance of renewable energy technology is pivotal to energy transitions, this study reflects a proactive attempt to understand agrivoltaics from a solar industry professional’s perspective to better understand the significant opportunities and barriers to development. This research suggests that agrivoltaics are potentially accretive to the long-term growth of the solar industry, possessing the capacity to increase social acceptance of local solar developments. While the agrivoltaic concept is widely supported by the participants in this study, popularity of an emerging technology among industry experts may not indicate local level acceptance of a specific development. As new energy technologies such as agrivoltaics transcend niche applications to become more prevalent, localized resistance is to be anticipated and the dimensions of social acceptance, including the opportunities and barriers associated with each dimension, can help inform decision making to enhance the growth of agrivoltaic development.

The Morris Ridge Solar Project is a proposed solar farm on approximately 1,060 acres in the Town of Mount Morris, southern Livingston County, New York. The project site is within an area farmed primarily in a cash cropping rotation. The Morris Ridge Solar project is being designed to integrate agricultural uses, including a managed grazing system that utilizes sheep grazing to control vegetation growth under and around the solar panels. Sheep grazing is a method of vegetation control used on solar facilities around the world and is increasingly being used in the Northeastern United States to provide a solution that can promote and incorporate an agricultural use within a solar photovoltaic facility. The Morris Ridge Solar project is also being planned to accommodate honeybees and honey production. Through the incorporation of pollinator-friendly vegetation into the project design, solar farms can create suitable habitat for honeybees. Co-locating honeybee apiaries and solar farms has been proven to be a successful method of integrating agricultural use at solar farms throughout North America. The Morris Ridge Solar project will seek to contract the grazing through local farmers who either currently own sheep or wish to expand sheep enterprises as part of their farm business. To engage with these farmers and determine which candidates are best fit for the contracted grazing, MRSEC and AVS have worked to conduct outreach locally and assess interest from the farm community. Initial interest has been solid, with several area farmers expressing interest in contract grazing either parts of the site or the entire site. The solar site will be seeded with a seed mix designed for the special circumstances of the site: grazing, honey production, low-growing, shade and sun tolerant. The seed mix will be selected based on soil testing results, which is scheduled for fall 2020. The seed mix will be something akin to Ernst Conservation Seed’s Fuzz & Buzz Mix. A mix of pasture grasses, legumes (all flowering plants), and forbs (more flowers), it is a diverse and robust blend designed to balance the needs of agrivoltaic production. The seed mix is integral to the vegetation management plan. The vegetation management is planned to support perennial pastures that nearly always have flowering plants. This perennial rotation of the sheep keeps vegetation in sequence of rest and grazing. This sequence is cyclical, and the structure allows the legumes and forbs time to flower from May to October. With the planned rotation of the sheep, the availability of nectar from flowering plants across a large area that are stimulated to bloom consistently throughout the season should allow the bees to thrive. EDF-Renewables has taken care to strategically plan for a high level of agricultural integration at the Morris Ridge Solar Facility. The solar facility is proposed to create a new opportunity for a livestock grazier and a commercial honey producer in the region. Over the rest of 2020, AVS and EDF-Renewables will work to find the right farm partners to facilitate the plans identified above. The construction plans will be fine-tuned with a grazing operation in mind. The future site graziers will have several years to bring their livestock operations up to speed in harmony with the construction schedule. Our team looks forward to project success that incorporates and strengthens the regional agricultural community in the Morris Ridge Solar Project.