Tag Archive for: AgriSolar

Case Study: Winston Cone Optics and Dairy Processing 

Winston Cone Optics’ installed pilot system on the roof of a dairy barn in California.

By Anna Richmond-Mueller, NCAT Energy Analyst

Thanks to the increase of solar photovoltaic sites in recent years, agrivoltaics has started to work its way into the public eye as a means of bridging the gap between land use for agricultural and energy production. By co-locating energy production with sustainable agriculture, the land that solar arrays occupy can continue to produce crops, provide forage for grazing animals, or even serve as a pollinator habitat for bees. Beyond photovoltaics, the broader umbrella of “agrisolar” also encompasses concentrated solar-thermal power (CSP), which can help decarbonize the agricultural processing space. Winston Cone Optics (WCO) in Merced, California, is at the forefront of this effort, helping dairy farmers reduce their propane consumption by using CSP to heat water for equipment sterilization.  

WCO’s CSP system was developed at University of California, Merced under the guidance of Dr. Roland Winston. The technology utilizes nonimaging optics, which allows the system to function in a stationary position. Compared to photovoltaic tracking systems – which adjust the solar panel’s angle throughout the day to follow the path of the sun – WCO’s system requires less upkeep and fewer parts, while simultaneously achieving 50 to 60% efficiency. The solar collectors pair nonimaging reflectors with evacuated tube receivers. These receiver tubes house a selectively coated fin that absorbs the concentrated thermal energy. As the fin increases in temperature, pressurized water is circulated through the tube and into a heat exchanger where the hot water can be passed into the hot water system. 

Schematic drawing of the dairy’s system. 

When WCO was looking for a pilot site, they learned of a local dairy building a fully automated freestall barn just down the road from their headquarters. They reached out to the farmer and offered to install their system in an effort to cut down the farm’s propane costs. Funding from California Energy Commission helped finance the project, which totaled around $50,000 not including labor. In October 2022, a 91-square-meter array mounted on the roof of the barn began pre-heating water for milking equipment sterilization. The system preheats 1,000 gallons of well water from 70 to 180 degrees Fahrenheit each day and collects it for use at any time in a hot water storage tank. It integrates seamlessly into the existing propane-fueled heating system, which now acts as a backup system to heat the water on cloudy days when the solar system can’t fully handle the demand. The system’s cost per kilowatt is almost half of what the farmer currently pays for propane, and it has reduced on-farm consumption for water heating by 70%. 

Close-up of the concentrated solar system on the barn roof. 

As farmers continue to search for ways to lower their operating costs and decrease their reliance on fossil fuels, WCO’s robust and uncomplicated system is an attractive solution showing great promise. The team emphasizes the adaptability of the system, as the modular collectors can easily be scaled up or down to meet the needs of a wide variety of processes. The modules are able to be installed on both flat and angled surfaces, making them easy to place on almost any rooftop and avoid taking up valuable ground space. The installation time is also impressively quick. The team first recommends conducting a thermal energy audit to ensure the building is properly insulated, followed by a period of time tracking the energy needs of the building’s current system. Once an understanding of the energy load has been established, the team knows how to size the CSP system properly for the process’s demands. Then, it may take as little as a few weeks to install the new system. Looking forward, the WCO team is excited to continue their work in the dairy space and hopes to expand their portfolio of sites across a variety of farms both big and small.  

Photos courtesy of: Winston Cone Optics 

AgriSolar News Roundup: Solar Lease Considerations, Pennsylvania Agrisolar Development, Agrisolar in Australia, California Agrisolar Politics

Things to Consider Before Signing a Solar Lease

“Part one of a three-part series on solar leases and considerations for lawyers and landowners. This is based on a presentation by Rusty Rumley, senior staff attorney, National Agricultural Law Center at the University of Arkansas System Division of Agriculture. The presentation was delivered at the tenth annual Mid-South Agricultural and Environmental Law Conference in Memphis, Tenn.” – Farmprogress.com 

Pennsylvania Group Pitches Farms on Solar Models

“Solar development on farmland is happening across central Pennsylvania — in some cases generating opposition from people who don’t like the look of solar panels and object to the loss of open land.

Pasa Sustainable Agriculture is working to introduce farmers to a different way of building solar farms that allows farming to continue and creates a smaller footprint. They hope it’s a way to address concerns in communities that have objected to large-scale solar. The model is called agrivoltaics, and it uses raised panels to generate solar energy while farming or livestock grazing continues beneath.” – stateimpact.npr.org

Australian Agrivoltaic Project Development Set to Move Forward

“A “farmer-led” utility-scale solar PV and battery storage agrivoltaics project in New South Wales, Australia, has been granted development consent.

The state’s government has decided to grant consent to the development application for Blind Creek Solar Farm. The project was originated by a group of farmers and is now being developed by Octopus Australia and the national Clean Energy Finance Corporation (CEFC) together with its founders.” – energystorage.com

A Second Amendment Amendment

“California may be a national leader in both solar energy and agriculture, but it’s lagging behind other states in combining the two. Putting solar panels directly on active farmland is supported by the Biden administration, which provided $8 million for projects last year. The Midwest and Southeast lead the country in the number of what are also known as agrisolar projects.

Early research suggests agrivoltaics can not only help produce renewable electricity, but also improve crop yields. “Sounds almost too good to be true,” California Food and Agriculture Secretary Karen Ross quipped today during a panel on the practice held by the California Council on Science and Technology. In California, growers are more used to fighting utility-scale solar developers eyeing their land.

Ross highlighted a proposal by state Sen. Steve Padilla (D-San Diego), SB 688, that would set up a grant program at the State Energy Resources Conservation and Development Commission for agrivoltaics research projects. The bill does not appropriate any funding.” – Politico.com

Solar Parks: A Review on Impacts, Mitigation Mechanism Through Agrivoltaics and Techno-economic Analysis

The current work has a reviewed agrivoltaic projects in India and identified the management practices, constraints, cost econmoics and policy framework. A review of works done on solar park impact assessment and mitigation mechanism by agrivoltaics are done in detail. The work has considered agrivoltaics from a social aspect and focused on impacts due to loss of livelihoods and associated externalities under social impact classification. The social impact assessment concludes that, livelihood impacts can lead to extinction of cultures, urban migrations, growth of uncontrolled peri‑urban regions, the long-term impacts are beyond economics.

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Shading Analysis of Agrivoltaic Systems

This study aims to discover how lettuce and potato crops are impacted by the shade of photovoltaic (PV) panels. Four scenarios are considered, with varying parameters such as latitude, azimuth, slope, and row distance between PV modules. The results reveal a significant potential for growing potatoes under PV modules. However, lettuce faces difficulties due to its high requirement for solar intensity (PAR), making it less adaptable to shade. The findings of this study indicate that crops like potatoes, which have a lower requirement for PAR, can be successfully cultivated in conjunction with PV systems.

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Grassland Carbon-Water Cycling is Minimally Impacted by a Photovoltaic Array

In this study, researchers used field measurements and a plant hydraulic model to quantify carbon-water cycling in a semi-arid C3 perennial grassland growing beneath a single-axis tracking solar array in Colorado, USA. Although the agrivoltaic array reduced light availability by 38%, net photosynthesis and aboveground net primary productivity were reduced by only 6–7% while evapotranspiration decreased by 1.3%. The minimal changes in carbon-water cycling occurred largely because plant photosynthetic traits underneath the panels changed to take advantage of the dynamic shading environment. The results indicate that agrivoltaic systems can serve as a scalable way to expand solar energy production while maintaining ecosystem function in managed grasslands, especially in climates where water is more limiting than light.

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Community Centered Solar Development (CCSD)Case Study Interviews

As part of Berkeley Lab’s Community-Centered Solar Development (CCSD) project, this research set out to explore deep insights and perceptions from large-scale solar (LSS) stakeholders that only qualitative data can provide to identify key factors driving project success or threatened failure. Case studies, such as those utilized in this research, are uniquely adept at capturing the subjective experience of individuals and at identifying variables, structures, and interactions between stakeholders. Our case studies included 54 semi-structured interviews across 7 different LSS sites, representing a diversity of geographies, project sizes (MW), site types (i.e., greenfield, agrivoltaic, and brownfield / contaminated sites), zoning jurisdiction types, and more. In addition to local residents living in close proximity to these LSS sites, we interviewed other key stakeholders involved in the projects such as developers, decision-makers, utility representatives, landowners, and individuals from community-based organizations. The overarching aim of this case study research was two-fold: (1) to inform subsequent tasks in the CCSD research project (including an upcoming national survey of LSS neighbors), and (2) to provide insights into the following set of research questions: -What are the key positive and negative drivers leading to support and opposition to LSS projects? -To what extent do LSS projects exacerbate or mitigate perceived inequities and marginalization within hosting communities and how can those inequities be mitigated going forward? -What strategies can communities employ to align LSS development with local land-use plans and community needs and values? 

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Visual Perception and Acceptance of Agrivoltaic in an Eye-Tracking Experiment in Germany

In this study, researchers tested hypotheses on the extent to which varying image content representing different types of grassland use affects the visual perception and acceptance of agrivoltaics. In the before-and-after comparison, the acceptance of agrivoltaics increased significantly only for grasslands and special crops. The results suggest that attitudes towards agrivoltaics are rather stable and cannot be easily modulated by additional information.

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Solar Shepherd in Massachusetts: Solar Grazing 

By Allen Puckett, NCAT Technical Writer 

July 2023 

The Solar Shepherd provides grazing services in Brookfield, Massachusetts, with 75 sheep that graze a solar array site owned by SWEB Development, a European clean energy firm. This beneficial partnership was born when SWEB reached out to Solar Shepherd for grazing services after seeing their solar-grazing sites on social media. Learn more about the partnership in the AgriSolar Clearinghouse’s video How a Shepherd and Solar Developer are Joining Forces to Grow Sheep, Clean Energy. 

Solar Shepherd’s founder and owner Dan Finnegan is a third- generation sheep farmer in eastern Massachusetts. His history working in a corporate environment led him to think more about what was important to him—the land, local farming, and clean energy. While he likes raising sheep, there wasn’t enough acreage for it to be profitable without agrisolar sites. 

“It wouldn’t be enough to produce a living for a family,” he said. “This is more than a hobby-farming operation. With solar grazing, we dramatically expand our flock. We work hard to be competitive with landscapers on these sites. The grazing fees mitigate the costs and pay down the investment to take the show on the road (transporting sheep to solar sites). We’re used to farming out the back door, and now we have sites spread hundreds of miles apart. The grazing fees make that cost affordable.”  

“I saw a solar array built on a lambing pasture, and a landscaper showed up with a tractor and started mowing up the solar arrays. He was going about 30 mph with a batwing sprayer and was mowing the rows and hosing down the panels around the arrays. I was thinking, they should just put the sheep down there and let them graze,” Dan recalled. 

Solar Grazing Site Specifications and Management  

The site is in a 15-acre array that produces 5 MW of DC and 3.375 MW of AC, enough to power approximately 1,100 homes. A landowner leases the land to SWEB, and SWEB hires Dan to graze the solar arrays with the sheep. The pricing is relatively the same as traditional mowing and gas-powered landscapers, but grazing sheep comes with many environmental benefits, such as enhanced landscape stabilization that directly benefits the solar companies. This stabilization includes deeper root systems on previously rocky terrain, improved turf health, and significant runoff reduction. 

Solar Shepherd practices rotational grazing on their sites, which allows more carbon in the soil and retains more moisture. “We see that impact very rapidly. There are some sites we had that, in just one year, the customer came to us and said, ‘I can’t believe the impact the sheep had on the vegetation sustainability. It was rocky before, and now there are deeper root systems, stabilized soil.’ Erosion is a big concern at the base of the panels. A direct benefit to the solar companies is stabilizing that ground,” Dan added. 

There’s also the “Fuzz and Buzz” – a solar seed blend used at the Brookfield site that benefits pollinators and sheep. It’s not as robust of a floral bloom, but the bees and sheep benefit greatly from this blend. A gas-powered mower removes all the vegetation on an array in a single day. The sheep take around a month to “mow” the same array. This allows valuable pollinator habitat to be left for the bees and birds. There’s good seed-to-solar contact, and the imprints from the sheep hooves allow the seeds to be captured in the soil. The sheep help the effectiveness of reseeding a site and some graziers will run the sheep back over the seeds to help stomp them down into the earth. 

Solar grazing includes running three main operations: a sheep farm, a trucking company (as you move the animals), and a commercial landscaping business. “It’s more than just opening the gate, throwing the sheep in there, and driving away. There are always some sites that require things outside the lines,” said Dan.  

Dan’s partner, border collie Reggie, has been vitally important in effectively managing the sheep on solar sites. In the trucking operation, sheep are loaded in and out of trucks over and over, and that requires collecting them from one site to another to be loaded into the trucks.  

Reggie is immensely valuable in this process. She rounds up the sheep quickly, whereas it would take multiple human workers significantly more time. She is vital to effective time management (and cost, if you consider paying multiple workers to round up sheep all the time). Reggie moves the sheep around the array in accordance with rotational grazing practices. 

Grant Incentives in Massachusetts 

Massachusetts does have a grant program for dual use of solar (Massachusetts SMART Initiative), but it is “written in such a fashion that it can be difficult to be profitable,” said Dan. The grant does not apply to sites that already exist, and it requires panels to be built 10 feet off the ground. Solar Shepherd has not received this grant and has also not yet grazed an array that fits the 10-foot grant requirement.  

Livestock production is diminishing in Massachusetts and what’s left is small-scale vegetable farming. Dan speculates that the state is writing laws for solar development incentives with this in mind instead of grazing sheep under solar panels. 

Community Response 

“The community loves what we’re up to,” said Dan. “We had about 500 comments (on the recent video featured on CBS) and all of them were loving what we are doing. There are a few political comments. So, grazing sheep on solar might bring some unification from a political perspective.”  

He also added that, “At least half the time I show up, there is a family there outside the gate at the fence watching the sheep. People are wanting to bring kids out to the sites to see the sheep. I’d like to do a program where people can come see them. We would love to host a solar event. We’re going to bring some sheep to town off the hill in Brookfield so people can see them and interact with them. I have a dream of bringing a bus load of kids out here to see how bees, sheep, and everything all come together.” 

Since the Brookfield location is an ancient hay site where indigenous peoples managed the land when colonists first arrived, not damaging the vegetation or compacting the soil during the solar array installation was very important. This priority to minimize damage to the land could have a positive impact on community support for a solar site, particularly on ancient farmland or similarly valued sites. Communities like to see that a (solar) development company cares about the land and the process of development. 

Considerations for New Sheep Graziers 

New sheep graziers or those thinking about getting into sheep grazing on solar sites should consider a couple of things throughout the process. Educating themselves on what’s happening on the solar array is very important. “They don’t have to be engineers,” says Dan, “but they should understand what’s happening and what the potential dangers are and keep themselves and animals away from those areas. Stay out of areas where you might think ‘I should have an electrician in there.’ These are areas that contain things like cable trays and equipment pads.”  

Don’t move forward with grazing a solar site if you haven’t walked the location and examined it for suitable conditions for your sheep. If construction techniques did not leave a space where you would feel comfortable leaving the sheep, such as poor wire management or dangerous or sharp edges on array components, it may be a good decision to decline grazing in that location.  Dan says the sites he turns down are for animal welfare reasons. There might not be enough nutrition on the site, but it is usually wiring management. A good perimeter fence can also make a site more ideal for sheep.  

Operating a grazing operation on your own property requires having a plan for food and water delivery, as well as for avoiding predation. A plan should be in place for responding to issues that may arise on the site and with little notice. Solar Shepherd has a 24-7 hotline for such issues. 

For fencing, Dan prefers to use electric netting, which provides effective  protection from predators. Coyotes prefer to go under the fence rather than over it, and considering such nuances in predator-prevention strategies can help design a fencing system that is most effective for your area and your circumstances. Hiring people who think from the sheep’s perspective is important, says Dan. Fortunately, he has not had any issues with predation to his sheep.  

The Future of Solar Shepherd and Solar Grazing 

The future of Solar Shepherd is looking bright. It originally took the company approximately one year to get hooves on the ground at a solar site. Now it only takes about a week or two. “I feel great about the solar grazing future and Solar Shepherd. The sales pitches are getting shorter and shorter. The world is becoming aware of this subject. Five years ago, it was, ‘You’re doing what?!’ The last pitch I gave was an hour-long presentation. I got 15 minutes into the meeting, and people said, ‘It’s great; we are ready to sign.’” 

Growing Green Brings Agrivoltaics to Community Gardens in Arizona 

Written for the AgriSolar Clearinghouse by Sarah Bendok, Growing Green 

I am a rising sophomore at Phoenix Country Day School. Since I was young, I have always loved gardening. Every summer, I visit my grandma’s village and work in her garden leisurely while observing other farmers in the community tirelessly performing back-breaking labor just to put food on the table. This love for gardening continued while the images of these farmers more vividly resonated in my memory. As I grew older, I started volunteering at community gardens in Arizona, such as Spaces of Opportunity, a 19-acre urban farm that promotes healthy food choices while allowing low-income individuals to grow and sell their produce. I also have volunteered with Tiger Mountain Foundation, an organization dedicated to giving jobs and empowering people in low-income communities through community gardens in South Phoenix. While volunteering, I saw how much effort and hard work these farmers put in just to take home meager earnings. At the same time, these farmers struggle with worsening environmental conditions and decreasing crop yields. Volunteering at community gardens made me realize there is a whole story behind where our food comes from, involving people making sacrifices to feed our population. I will never forget the smile on a farmer’s face when he harvested 10 pounds of pepper. What if I could improve his working conditions? What if I could decrease the number of resources he uses for agriculture so he can earn more profit? What if I could plant the seeds of a more equitable, sustainable agricultural system in South Phoenix? 

Workers rely only on their crops for food and income at the community gardens where I have volunteered. Since they do not have the money for the same technologies that large-scale farms have, they depend on their natural resources to help them grow their crops through agroforestry and other natural practices. Instead of destroying the biodiversity to expand their farms, they integrate different trees, shrubs, and other plants to improve soil quality, reduce water use, and use them as natural pesticides to drive insects and other pests away. By integrating these natural tools, they could increase their crop yield. Working at these gardens and learning how they grow their crops, I became interested in how we can apply these concepts to all farms and expand the use of widespread and futuristic, sustainable technologies.  

University of Arizona graduate student Nesrine Rouini (left) and Sarah Bendok at Biosphere 2’s agrivoltaic solar array. Photo: NCAT 

This interest made me want to contribute to making agriculture more sustainable, especially at the community gardens where I have volunteered. So, I created a 501(c)(3) nonprofit called Growing Green to help fund and implement eco-friendly technologies at these farms. Our primary goal at Growing Green is to promote technologies at the intersection of agriculture and sustainability. One of the projects I have been working on through Growing Green is creating an agrivoltaics system at Spaces of Opportunity. I reached out to AgriSolar Clearinghouse, which allowed me to be in their peer-to-peer mentoring program by connecting me with Professor Greg Barron-Gafford and his team from the University of Arizona, Nesrine Rouini, and Alyssa Salazar. They have provided me with mentorship on the design of the agrivoltaics system and phenology data collection. In addition, they invited me to an agrivoltaics farm-to-table event at Biosphere 2, where I presented my project to the attendees and could sample dishes prepared with the vegetables grown under solar panels. The food was amazing, and the vegetables did not taste any different from the ones that are not grown with agrivoltaics. Separately, I have worked with Fundusol LLC, which has also helped me design the agrivoltaics system by entering the location of the system and crops to be planted into their proprietary algorithm to determine the optimal angle and spacing of the solar panels. Because of these mentorships, I have been able to teach everything I learned to farmers, solar developers, and others in my community about the benefits agrivoltaics and the significant and positive changes it could bring if implemented.  

To build this 5-KW agrivoltaic system, I connected with FOREnergy and Titan Solar for the installation of the solar array. In June, we had the site surveyed and are in the process of submitting permits to the City of Phoenix. The anticipated cost of this project is $20,000, and I am working on getting donations to be able to finance this project through community events, presentations, grants, and my website.   

Site survey with members of Spaces of Opportunity, Titan Solar, and Sarah Bendok to map out the system. Photo: Growing Green 

Separately, I was able to build a smaller agrivoltaics system over a raised garden bed at Spaces of Opportunity with donations from different local organizations to educate the community on the benefits of agrivoltaics while doing small-scale research. I have planted two types of cherry tomatoes and chiltepin peppers in this bed, but I plan to test crops native to Arizona in this location later on. I am also in the process of building another agrivoltaics raised garden bed at Garden of Tomorrow. There, I hope to plant a variety of crops that have not yet been tested with agrivoltaics to be able to continue to learn about which crops benefit from this technology. Although these beds are small-scale, I have started collecting data and educating the community on agrivoltaics by involving adult volunteers from the Desert Botanical Garden and employees from Tiger Mountain Foundation. I have connected with teachers from a low-income school near Spaces of Opportunity to engage students on these projects to help them learn more about sustainability within farming and renewable energy. 

Dan Mullaney from FOREnergy and Sarah Bendok installing the garden bed solar panel at Spaces of Opportunity. Photo: Growing Green

Without the guidance and support of Stacie Peterson and Anna Adair from AgriSolar Clearinghouse, I would not have been able to come this far with my projects. I am very grateful for the opportunities and connections they have provided me with and hope to continue to promote agrivoltaics alongside them. 

If you would like to support, partner with, or collaborate on this initiative, please email me at contactus@growing-green.org or visit our website.

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Fact Sheet: The Economics of Solar Grazing

Solar grazing is on the rise in the United States with dozens of new operations springing up across the country. However, with all of this growth in mind, an important question remains: if a grazier wants to enter the solar grazing market, how much will it cost, and how much revenue can they generate? Budget templates exist that can provide a grazier with guidelines, but hard data on grazier costs and revenues is more difficult to come by.

Researchers at the University of Illinois Urbana-Champaign’s Bock Agricultural Law & Policy Program set out to answer this question as a project through the National Renewable Energy Laboratory’s ASTRO InSPIRE Seed Grant Program. Undergraduate students Tyler Swanson and Quin Karhoff, supported by Post-Doctoral Researcher Jessica Guarino and Professor A. Bryan Endres, conducted a survey of American solar grazing practitioners to gather data on common capital and labor investments, as well as operation sizes and revenue streams. The researchers hope that the findings of the survey will help graziers interested in entering the solar grazing market better understand what costs and revenues they can expect and contribute to more accurate budget tools for potential solar graziers. The results of the survey are included in their fact sheet The Economics of Solar Grazing.

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