By Stephanie Hince, AES

Although Grafton, Massachusetts, is just an hour west of Boston, life there is very different. Grafton is a friendly country town with a lovely historical feel. It has been a farming community for centuries, where thriving cotton, grist, and paper mills once dotted the landscape.

Whereas the Quinsigamond River once powered numerous mills, a newly constructed solar farm owned by AES is incorporating two Grafton traditions: clean energy and agricultural production. Let’s explore how our solar project brings together key stakeholders to help protect farmland in Grafton and beyond.

Grafton Solar’s On-site Agricultural Production

This solar installation is located on Knowlton Farm, a family farm operating for over 150 years. Instead of merely leasing fallow farmland for the project, the solar farm was designed with on-site agricultural production and research in mind from the start.

Grafton Solar is a 2-megawatt community solar farm with a 1.4-megawatt battery energy storage system. Many stakeholders have come together with a shared vision of clean energy, food production, and learning, which is making this endeavor a success.

Our current and prospective project partners include the U.S. Department of Energy, Massachusetts Department of Energy Resources, Massachusetts Department of Agricultural Resources, UMass Amherst, American Farmland Trust, and Cornell University. In December 2020, AES acquired the Grafton Solar project from BlueWave.

What Made This Solar Farm Unique from Day 1

An agricultural plan was created early in the design phase as a collaboration between Paul Knowlton, a fifth-generation farmer and current operator of Knowlton Farms, Iain Ward of Solar Agricultural Services, and BlueWave Solar. Today, that plan has come to fruition. With a keen eye, passersby will notice something very different at our project site.

Borrego, the construction contractor, elevated the solar modules to a height of 8 to 14 feet and created large inter-row spacing to allow cattle grazing and access for farm equipment. The agricultural integration component of the project began last May with the planting of squash and lettuce, as well as cattle grazing.

There is still much to be learned. Solar developers and farmers need a greater understanding of how to make widespread use of agrivoltaics cost-effective and practical. Thus, Grafton Solar provides opportunities to advance its application on other project sites and by other solar developers across the U.S.

All photos courtesy of the AgriSolar Clearinghouse

Grafton Solar is Now a Living Laboratory

We intentionally reserved a section of the project area for new and existing research partnerships – Grafton Solar is an official hub of activity for learning about agrivoltaics. Research partners, UMass Amherst and the American Farmland Trust, are working to establish site trials to assess crop productivity, soil health, and micro-climatic conditions, thanks to a grant from the U.S. Department of Energy Solar Energy Technology Office (SETO). Once available, research information will be made publicly available so that others in the solar and agricultural industries can learn and benefit from their findings.

Solar Incentives Helped Make This Innovative Project Possible

In Massachusetts, revenue for solar projects is provided through the SMART program, which starts with a fixed compensation rate for projects. A project can obtain different adders based on project attributes, which increases the rate and therefore the benefits to the project developer and landowner. Some of these adders include making a project a community solar farm, adding battery storage, or having a dual-use agricultural component. Grafton Solar does all three.

Community solar projects expand access to renewable energy and allow subscribers like households, businesses, educational institutions, municipalities, and others to experience the same benefits of solar power without having to install a solar array on their own property. Battery storage helps to mitigate the intermittent nature of solar energy by storing solar energy when production is high and electricity demand is low and promotes reliable, carbon-free power by making solar energy available when utility companies need it most. Thus, it reduces the need to use more polluting power plants when power demand is high.

Grafton Solar is built around the community solar model, incorporates battery storage, and is supporting a legacy of agricultural production at Knowlton Farm – a win-win-win. By leveraging Massachusetts’ innovative state-level solar incentives (which includes the only rate-adder for agrivoltaics in the U.S.), Grafton Solar is delivering multiple co-benefits to the community and showcasing that solar projects can do much more than produce power on site.

Protecting Farmland When Developing Solar Energy Projects

Grafton Solar is AES’ first agrivoltaic site in the Northeast and is consistent with our vision to provide the smarter, greener energy solutions the world needs. According to a report by the American Farmland Trust, the U.S. lost or compromised 2,000 acres of farmland and ranchland every day from 2001 to 2016.

If this trend continues, an area nearly the size of South Carolina will be lost between 2016 and 2040, which could be detrimental to food security. Many farmers across the U.S., like Paul Knowlton, are looking for new revenue streams and ways to keep family farms operating for future generations. In addition to producing food, family farms are also about preserving a way of life.

At AES, we understand the importance of protecting farmland when integrating renewable energy projects into the landscape. Solar energy development and farm viability can go hand-in-hand when taking a thoughtful, dual-use approach.

Using Partnerships to Maximize Opportunities

We understand the importance of land and are actively working to create synergies between renewable energy development and agricultural land use. In addition to successfully co-locating crop growth and grazing at Grafton Solar, we have implemented active sheep grazing on thousands of acres of land at utility-scale solar sites, and we are participating in research partnerships in various regions across the U.S. to better understand how we can harvest clean energy and food from the same land.

We know that the success of our company is only as strong as the partnerships within the communities where we operate, so we develop, build, and manage projects that maximize value to a variety of stakeholders. Ultimately, we need both clean energy and productive farmland, not just one or the other.

Grafton Solar provides an excellent opportunity to collaborate with the research community and the Knowlton family to further our understanding of how to make agrivoltaics practical and more widespread. The project symbolizes preserving a way of life that spans many generations while embracing innovative clean energy technologies that promote food security, reliable energy, and a cleaner environment.

The U.S. Department of Energy and the Solar Energy Technologies Office (SETO) have developed new resources to help Americans navigate changes in the solar Investment Tax Credit (ITC) that occurred after the passing of the Inflation Reduction Act (IRA) in 2022. The resources, intended for business owners, homeowners, and manufacturers, provide in-depth overviews of the ITC, Production Tax Credit (PTC), and Advanced Manufacturing Production Tax Credit (MPTC).  

The resources explain the process of claiming tax credits, answer frequently asked questions, and explain the tax code through examples. Titles include Homeowner’s Guide to the Federal Tax Credit for Solar Photovoltaics, Federal Tax Credits for Businesses, Federal Solar Tax Credits for Manufacturers, Get Answers to the Future of Solar Energy Development, and More Questions about IRA’s Tax Incentives. 

Homeowner’s Guide to the Federal Tax Credit for Solar Photovoltaics 

This resource will help homeowners understand how the IRA can help them save money on solar energy. It explains that the federal residential solar energy tax credit can be claimed on federal income taxes for a percentage of the taxpayer’s cost to install a photovoltaic system. 

The guide includes an explanation of the federal solar tax credit and answers questions about eligibility to claim the credit. A list of expenses that can be included in the tax credit is provided, along with descriptions of how other incentives might affect the tax credit, such as payments for renewable energy certificates, state tax credits, and state rebates.  

Federal Tax Credits for Businesses 

This resource provides an overview of the tax credits available for businesses, including for purchase of solar energy systems. It includes a summary of the ITC and the PTC values from 2006 to 2033. The chart includes base rates and full rates for both credits. 

The guide also explains which credit is right for you, what expenses are eligible for the ITC, and labor requirements for projects, as well as providing details on bonus credits, including a low-income bonus. You’ll also find descriptions of how tax-exempt organizations can benefit from the federal tax credit for businesses. You can also learn what happens to unused tax credits, including tax equity financing details and carryback and carryforward rules.  

Federal Solar Tax Credits for Manufacturers 

This resource  explains the Advanced Manufacturing Production Tax Credit (45X MPTC) and the Advanced Energy Project Investment Tax Credit (48C ITC) and helps manufacturers decide which tax credit is best for them, as they cannot claim both.  

The guide summarizes eligibility guidelines for advanced manufacturing production tax credits, including PV module and subcomponents, PV inverters, PV tracking systems, batteries, and critical minerals. It includes a useful chart that shows when tax credits phase out and the tax credit for eligible U.S.-produced components in various years. 

You’ll also find information of 48 ITC, including availability of credits, criteria for application, and details about the direct-pay option and transfer of credit for manufacturers. 

Webinar: Reaching for the Solar Future: How the Inflation Reduction Act Impacts Solar Deployment and Expands Manufacturing 

This webinar discusses the broader implications of SETO’s Solar Futures Study analysis. It answers questions such as: Are there any incentives for nonprofit organizations to install clean energy devices—solar or heat pumps? Is there a sense of what the application process for the ITC for nontaxable entities will look like, and timing for when we might know? Do school districts qualify for the 30% ITC, and can non-tax entities pass the savings along to the installer or designer like E-Pact? 

With these resources available, Americans can now confidently navigate the changes in the ITC resulting from the IRA. Homeowners, businesses, and manufacturers will benefit from the examples and explanations provided in these resources surrounding solar tax credits and incentives.  

Rebecca A. Efroymson, Environmental Scientist, Oak Ridge National Laboratory); and Jonathan M. O. Scurlock, Chief Adviser for Renewable Energy & Climate Change, National Farmers’ Union of England and Wales

Solar photovoltaic (PV) power, the most popular form of renewable energy on farms, is being adopted all over the world. Growers and processors of food worldwide have a long history of using the sun’s energy to produce and dry their crops, and solar PV is adding a modern twist to our relationship with the sun. It is no surprise that some of the best locations on Earth for harnessing solar energy are often ideal places for agriculture and horticulture. However, intelligent design for multi-purpose land use can alleviate real or perceived conflicts between energy and food production. Solar modules can shade crops where light intensity is in excess of crop requirements, reducing water evaporation; they can be mounted on agricultural buildings to power farm business energy needs; and they can export low-carbon electricity to meet wider demands for “green” power and the transition to a “net zero” global economy.

We use the term agrivoltaics broadly to describe any combination of agricultural activity and solar electricity production, but outside the USA, the term usually refers more specifically to the intimate juxtaposition of solar modules and agricultural land use. Examples include PV modules mounted at a height of several meters to allow access to land below by farm machinery or large livestock, where they provide shelter from storms or excessive solar radiation, and the integration of solar PV into greenhouses for crop protection.

We caught up with a range of projects across three continents to report upon their objectives and their future prospects.

Around 30% of British farmers have either rooftop or ground-mounted solar energy. The National Farmers Union (NFU) aspires to the goal that every farmer and grower have the opportunity to become a net exporter of low-carbon energy. The falling capital cost of both solar and battery electricity storage has resulted in a growing pipeline of solar installations across a range of sizes, including large 100-hectare (ha) and 1,000-ha solar farm projects, largely independent of government policy support. The NFU advises farmers that solar PV can be deployed across entire fields, as small, ground-mounted installations around field margins or adjacent to farmyards, on farm buildings, and on domestic rooftops. Developers of solar farms are encouraged by the NFU to follow best practice guidelines for multi-purpose land use, combining energy production, continued agricultural management such as grazing, and creation of wildlife habitat. NFU’s strong preference is for large-scale solar farm development to be located on lower-quality agricultural land, avoiding as much as possible the most productive and versatile soils. Roof-mounted solar systems in Britain continue to offer a sound investment, making between 10% and 25% simple return on capital annually at current electricity prices, depending on how much of the generated power is used on-site. At of the end of 2021, about 70% of the United Kingdom’s 14 gigawatts of solar power generation capacity was located in the agricultural sector.

Multi-purpose land use – sheep grazing and hedgerows of natural vegetation around a large (44-megawatt) solar farm near Haverfordwest in the United Kingdom. Photo Credit: Jonathan Scurlock

In the Netherlands, the Symbizon project at Almere, near Amsterdam, has brought together a Swedish energy company with Dutch researchers and a private organic farm to construct a 700-kilowatt solar park with alternating strips of PV modules and rows of crops. Starting in spring 2023, the production of herbs will be investigated, and potatoes, beans, beetroot, broccoli, and grains may be included in this pilot study. Pivoting double-sided (bifacial) solar modules will catch the reflected light from soil and crops.

Nearby in Germany, Goldbeck Solar is an innovator in solar agrivoltaic structures. The company has developed a system of solar PV arches that slide on side rails, allowing farmers to shelter or expose various crops. Typically oriented east to west for maximum solar energy yield, the arches span up to 9 meters, at a height of 2.5 to 3 meters, allowing a degree of control over temperature, humidity, and light. These agrivoltaic modules can also provide shelter for livestock from extreme weather, such as high temperatures and hail. The modules are currently undergoing trials in the four-year Sunbiose project in the Netherlands, which had already succeeded in growing raspberries under the partial shelter of solar PV modules. 

Agrivoltaics are being tested in East Africa, where their shade can reduce heat stress and water loss, and farmer incomes in disadvantaged rural communities may be improved. An experimental facility opened in 2022 in Insinya, Kenya, through partnership with Universities of Sheffield, York and Teesside in the United Kingdom, the Stockholm Environment Institute, World Agroforestry, the Centre for Research in Energy and Energy Conservation, and the African Centre for Technology Studies. Some 180 PV modules, each 345 watts, have been installed about 3 meters above the ground, allowing a variety of crops to be grown under the shade from the strong equatorial sun. Geoffrey Kamadi of The Guardian reports that benefits include improved yields of cabbage, eggplant, and lettuce; a reduction in water loss; and a reduction in high daytime temperatures and UV damage.

Small-scale agrivoltaic development (less than 0.1 ha) has progressed rapidly in Japan, producing 0.8% of the total solar power generated in the country in 2019. Japan has perhaps the greatest number of agrivoltaic farms to date, with more than 120 plant species being cultivated on agrivoltaic farms. The Solarsharing Network provides a catalog of 27 agricultural crops (Solar Sharing for FUN | SOLAR SHARING NETWORK| Solar Sharing Association of Japan ( and their light needs. Innovative crop systems include tea, according to Makoto Tajima and Tetsunari Lida of the Institute for Sustainable Energy Policies.

One pilot agrivoltaic project in New Zealand is seeking low-growing flowering plants like alyssum to attract bees and reflect light up to rows of bifacial PV modules. The high energy demand of irrigation systems can benefit from on-farm solar energy. In New Zealand, as in the U.S., UK, and Australia, sheep and other small livestock graze under solar modules, avoiding the need for mowing. As New Zealand reporter Delwyn Dickey notes, the success of such large-scale agrivoltaic systems (i.e., solar farms) may be determined by an insistence upon dual land use during the consenting process and the willingness of solar energy development companies to adopt dual land use.

Clearly, from small-scale intimate mingling of solar PV with agricultural production to multi-purpose land use in the largest of solar farms, the merits of harvesting the sun’s energy twice are appreciated the world over. The outlook for agrivoltaics is bright indeed.

By David Murray

In the 1940s, my great-grandfather purchased a small farm in the Hudson Valley of New York. He raised chickens and grew tomatoes, strawberries, and other crops until he passed away. My extended family treasures this farm, but with every passing year, maintaining it becomes less economic. The temptation to sell the property gets stronger.

Thousands of small farmers across America share my family’s story. The agriculture industry is increasingly consolidated, moving to a large, corporate business model. Farming technology has advanced rapidly, leading to crop prices are driven low. Small, independent farmers are often pushed out of the market. Meanwhile, real estate development in rural areas and suburban sprawl creates a pull: from 2001 to 2016, the U.S. converted 11 million acres of farmland to non-agricultural uses, with low density residential land use as the primary driver.

On one hand, the trend is unsurprising: as we become more efficient at growing food, we require less land – and fewer people – – to farm. On the other hand, small farmers play an important role in our food system, and families like mine should be able to pass a successful operation down to the next generation. For many families, solar energy provides that opportunity.

Leasing land to a solar developer provides stable, consistent income, helping some farmers avoid having to sell the land, which often gets converted to housing, commercial real estate, or other uses. In this manner, solar energy protects against what conservation organizations fear the most: low-density, suburban sprawl.

Solar energy development can also preserve the land: after approximately 30 years, the next generation can convert the property back to agricultural use. Finally, many farmers are already accustomed to supporting America’s energy needs: over 30 million acres of farmland are used to grow corn for ethanol.

Of course, farmers need to think long term: what are the impacts to the land from solar development? One benefit is nutrient runoff: solar facilities require less fertilizer than most crops; thus, nutrient runoff from solar facilities is typically less than the pre-existing agricultural use. Native grasses and legumes also mitigate erosion and improve water quality by intercepting sediment and nutrients. Solar development also cuts down on pesticide and insecticide use. Herbicide may be used during the site preparation process, but more sparingly once the facility is in operation. For arid regions, solar reduces water use – leaving an increasingly valuable resource to neighboring farming operations.

However, for families like mine that want continue using our farm to grow food and feed, agrivoltaics provides an exciting opportunity. This is why the American Clean Power Association is happy to work with the National Center for Appropriate Technology’s AgriSolar Clearinghouse to make agrivoltaics an increasingly financially feasible option for farmers.

Solar grazing is a bright spot. While letting sheep into an active power plant comes with a unique set of challenges, in certain cases it can be cheaper than a traditional landscaping crew. Data from the American Solar Grazing Association shows smaller projects are more likely to use solar grazing, but the association recently noted that a 200-megawatt (MW) solar project is slated to incorporate sheep into its vegetative management plan. For sites where solar grazing works, it can be an excellent win-win-win.

In the meantime, the industry is working to bring down costs of other forms of agrivoltaics, such as crop production underneath panels. A key challenge is raising the height of solar panels to accommodate farming. Unfortunately, raising solar panels significantly increases costs, as the piles need to be taller and driven further into the ground. Expensive machinery – such as a scissor lift – is needed to install piles deep enough to ensure they are secured properly to resist heavy winds. These lifts are not designed for use on solar sites. Furthermore, this process requires more labor to successfully deploy the equipment. This is an example of a major challenge that ACP is excited to work with NCAT on to make agrivoltaics more widespread.

We are aiming for a future where many types of agrivoltaics can scale, while ensuring that solar energy remains one of the cheapest forms of new energy generation. Thus, ACP will continue engaging with NCAT to identify ways to bring down the costs of agrivoltaic projects and continue to foster partnerships between the solar industry and agriculture sector.

David Murray is the Director of Solar Policy at the American Clean Power Association.

Merging community solar and agrisolar could aid the Department of Energy’s (DOE) goal of saving $1 billion in energy costs through community solar by 2025. Not only would merging community solar and agrisolar help DOE reach that goal, but would also provide other opportunities and benefits such as the regeneration of soil on solar sites, reducing fuel-operated maintenance demands, and increasing the likelihood of future solar development(s). 

What is community solar? 

Community solar could be an ideal method for low-income households who might be looking to use solar energy and use Low-Income Home Energy Assistance Program (LIHEAP) assistance to pay for their energy bills. LIHEAP funds cannot be used for things like up-front installation costs of typical solar participation methods (non-community solar) or the household ultimately owning the solar equipment. Community solar participation eliminates these issues due to the solar farm and panels not being developed, owned or operated by the LIHEAP recipient.  

LIHEAP Participants Would Lead to More Energy Savings 

Community solar often includes what is known as subscription-based community solar programs (SBCSPs), where a household “rents” solar panels and uses solar energy without the associated conditions and costs of installing solar panels, operating them, or owning them. These conditions of using solar energy typically would not qualify a low-income household to use LIHEAP funds for solar fuel. However, SBCSPs could provide a way for low-income households to be able to use LIHEAP benefit payments for solar fuel through subscription-based community solar programs because the household would not ultimately own the equipment or have to pay for its installation or maintenance costs. 

If LIHEAP participants are eligible for SBCSPs, then more people can participate in saving energy by using community agrisolar, which ultimately assists in the identified goal of the Department of Energy (DOE) in reaching $1 billion in energy savings through community solar by 2025. 

Why merge agrisolar with community solar? 

Community solar has been identified by DOE as a method of reaching energy savings goals by 2025, which includes saving $1 billion in energy costs. Merging agrisolar with community solar developments would not only aid in significant energy savings but would also make future solar developments more likely to be approved—expanding energy savings even further. 

Agrisolar operations like the Cabriejo Ranch in Missouri has shown that agrisolar provides a variety of energy saving methods as well as regenerating the land used by solar farms. The ranch uses Dorper sheep to manage the vegetation on solar operations, which drastically reduces the use of fuel-operated maintenance equipment typically used to manage vegetation. The sheep not only reduce these energy costs, but dramatically increase the health of the soil .  

The likelihood of a solar farm being approved for development is higher when Agrisolar is incorporated into the operations. This was seen in the Garnet Mesa project that was denied due to concerns about losing valuable farmland to the solar-farm development. The project was approved after changes were made to include 1,000 grazing sheep on the solar farm. 

The Possibilities of Merging Agrisolar and Community Solar   

 More participants saving more energy would be a win-win for reaching energy-and-cost savings goals.  

Not only do energy savings goals have a higher likelihood of being achieved through merging community solar and agrisolar, but other benefits of using agrisolar would also be made possible, such as regenerating soil health through grazing practices and supporting  job creations in local communities such as grazing management and farm operations jobs created in Missouri. These benefits of using agrisolar in solar development increases the likelihood of future solar developments by proving the land can be effectively utilized while occupied by solar equipment and operations.  

By Stacie Peterson, PhD

See more photos from the tour in the AgriSolar Flickr album here: Follow the Sun Tour: Massachusetts | Flickr

The farmlands of Massachusetts are cherished landscapes, steeped in cultural significance and family connections. Coming from the drought-ridden western United States, I was struck first by the lack of irrigation pivots and the lushness of the landscape, even after a heatwave uncommon to the area. I then scanned the rolling hills for solar, excited to see the Massachusetts SMART program in action. I wasn’t disappointed. The solar array at the University of Massachusetts South Deerfield Research Farm presented a picture-perfect site to start our tour.

Follow the Sun Tour Attendees at the UMass South Deerfield Agrivoltaic Research Site

The tour attendees matched my enthusiasm by showing up early and leaning over the fence to better view the solar farm. We were welcomed by Dr. Dwayne Berger from University of Massachusetts, who gave a presentation on the DOE SETO-funded research at the farm. This project involves the study of crop productivity on crops planted under a solar array installed by Hyperion Solar.

Next, Gerry Palano gave a presentation on Massachusetts Agricultural Solar Tariff Generation Units and their relation to agrivoltaics in the Massachusetts Solar Massachusetts Renewable Target (SMART) Program, which provides financial incentives for solar projects. From there, we went out to the farm, where Jake Marley from Hyperion Systems described the solar array design, and Dr. Stephen Herbert discussed the current crops and research at the array.After a quick lunch, we boarded the bus and started our mobile conference of speakers. Dr. Zach Goff-Eldredge kicked off the bus tour with a discussion of DOE SETO’s programs and their support of agrivoltaics. 

Dr. Zach Goff-Eldredge Manager of DOE SETO Agrivoltaic Programs

AgriSolar Clearinghouse consultant Alexis Pascaris of AgriSolar Consulting then gave an inspiring talk, envisioning the future of agrisolar from the perspective of farmers, landowners, solar developers, and community members.    

Candace Rossi from the New York State Energy Research and Development Authority (NYSERDA) then spoke to the group about the impactful programs in New York State and their relevance to AgriSolar around the country. We arrived at Nate Tassinari’s family farm in Monson with the sun high overhead. Nate welcomed the group to his home and talked about the Million Little Sunbeams project he developed  to preserve his family’s farmlands. The farm includes co-located solar and hay, an apiary, and an orchard. As shown in the photo, the 250-kW solar array, installed by Sunbug Solar, has an elevated racking system that accommodates haying equipment. The panels are bifacial, and Nate described the increased solar energy production from the bifacial panels as a result of both hay and snow reflections.

The Million Little Sunbeams project created a financial pathway for Nate and his family to own the land and the solar system; this project does not involve a lease to a solar developer.  Nate graciously fielded questions about his process and Gerry Palano fielded questions about the SMART funding piece of the project. Nick d’Arbeloff from Sunbug Solar fielded technical questions about the solar array and site design.

Nate Tassinari at Million Little Sunbeams Solar and Hay Site

We then travelled to a late-breaking and welcome addition to our tour with Dan Finnegan from Solar Shepherd in Brookfield. On the way, Lexie Hain, former president of the American Solar Grazing Association and current Director of Agrivoltaics and Land Management at Lightsource BP, gave the group a background on solar grazing.When we arrived at Solar Shepherd, Dan’s assistant, Reggie the Wonder Dog, herded the sheep toward the gate to greet us and then herded them to the solar array, so we could witness solar grazing first- hand. Dan described his solar grazing work in Massachusetts and talked with tour members about the practicalities of solar grazing, such as sheep transportation, water needs, leasing, and solar grazing contracts.

Solar Grazing with Solar Shepherd

After Solar Shepherd, we boarded the bus to travel to our last agrisolar site: Grafton Solar at Knowlton Farms. On the way, we heard from AgriSolar Clearinghouse stakeholder Ethan Winter from American Farmland Trust (AFT) about AFT work on smart solar siting, agrivoltaics, and at  

Grafton Solar at Knowlton Farms provided the tour group with the opportunity to see a large-scale agrisolar site. The 334-acre hay farm includes solar developed in several phases on 75 acres. In addition to Paul Knowlton, fourth-generation family owner of Knowlton Farms, the project includes a slew of agrivoltaic advocates, solar developers, researchers, and the State of Massachusetts. 

The agrisolar portion of Knowlton Farms, known as Grafton Solar, is owned and operated by AES Corporation, which pays Knowlton Farms lease payments and a stipend for the cost of farming. The Massachusetts SMART program provided incentives for the project and the University of Massachusetts and American Farmland Trust study the impact of the solar array on crop yields and soil conditions.

Paul Knowlton, at Grafton Solar at Knowlton Farms

Paul Knowlton talked with the group about his decision to enter into a lease agreement for solar at his farm, its positive financial impact to his family business, and his hopes that the project will help keep the farm in the family well into the future. Dr. Sam Glaze-Corcoran from University of Massachusetts Amherst described soil and crop studies and, along with Gerry Palano and Swayne Berger, fielded questions about how those studies inform University of Massachusetts recommendations to the SMART program.  Ian Ward, of Solar Agricultural Services, discussed the site design, plantings, and the potential for this project to serve as an example for other farmers in New England. Ian’s advocacy centers on keeping farmlands in the hands of farmers and in preserving farmlands for the future. Julie Fine, AFT’s Climate and agriculture specialist then led the group crop co-location potion of the site and described her work assessing impacts to crops, soil, and ecosystem services.

The group then boarded the bus for the ride back to Amherst, full of ideas, connections, and energy. Charles Gould, from Michigan State University Extension, talked about his impressions of the day, his work in agrivoltaics, and his thoughts on the future. Judy Anderson, of Community Consultants, led the tour group in a roundtable discussion of the tour, ways to engage policy makers, and how to move forward in a way that supports agrisolar throughout the country. 

Million Little Sunbeams AgriSolar Site

Tours like this are months in the making. From scouting potential sites and tour routes to meetings with farms, solar developers, local governments, and potential speakers. They have the complexity and logistics of a mobile conference. This tour couldn’t have happened without the help of Alexis Pascaris of AgriSolar Consulting and Jake Marley of Hyperion Systems. They were at the heart of this tour and worked with me for months as we planned, connected, and revised. They were flexible with last-minute changes, and I deeply appreciate their contributions to the tour.

I’d like to thank University of Massachusetts for hosting the event at the South Deerfield farm and for allowing us to gather in their meeting space. Thank you, too, to Nate Tassinari for hosting us at his home in Monson; I appreciate his flexibility with last-minute schedule changes and his warm and insightful tour of his farm. Dan Finnegan and Reggie the Wonder Dog deserve a huge round of applause for treating the group to a demonstration of solar grazing in Brookfield. And thank you to Paul Knowlton, The AES Corporation, Ian Ward, Glaze-Corcoran, Julie Fine, Dwayne Berger, and Gerry Palano for the excellent tour of Knowlton Farms. It is a model agrisolar site with impressive research and support.

I’d like to thank the Solar Energy Technology Office of the U.S. Department of Energy for funding this work and Dr. Zach Goff-Eldredge for attending the tour. His support of agrivoltaics is evident around the country and the work the SETO team is doing in this space is creating a pathway for co-located agriculture and solar that works for farmers, community members, and solar developers.

NCAT’s Sustainable Energy and Sustainable Agriculture Teams Joining Forces for AgriSolar

I’d like to thank Danielle Miska, Andy Pressman, and Chris Lent from NCAT for their work on this project and for the AgriSolar Clearinghouse team at NCAT, around the country who cheered us on. I’d also like to thank Nicole Karr, our photographer. It is her beautiful photos throughout this blog. Finally, I’d like to express my gratitude to the tour attendees. The Follow the Sun Tour is one way the AgriSolar Clearinghouse works to build community, relationships, and trusted, practical information and I thank you all for joining us. It was a marathon tour of presentations, site tours, bus speakers, roundtables, networking, honey sticks, and fun. Your energy and enthusiasm are inspiring, and I can’t wait to see you on the road again.

See more photos from the tour in the AgriSolar Flickr album here: Follow the Sun Tour: Massachusetts | Flickr.

By: Stacie Peterson

Minnesota is a leader in agrisolar, thanks to innovative policies, inspiring research, and a committed network of agrivoltaic and pollinator advocates. The Follow the Sun Tour had the opportunity to visit four of Minnesota’s AgriSolar sites on an action-packed summer day full of site visits, speakers, and a social networking event on August 4, 2022. 

We began the day by gathering at Connexus Energy’s Headquarters. After group introductions, we boarded a bus, which served as a mobile conference room, and heard from our first speaker, Heidi Kolbeck-Urlacher from Center for Rural Affairs. Heidi spoke about the Center’s work in agrivoltaics and their work as a partner of the AgriSolar Clearinghouse.

Heidi Kokbeck-Urlacher Speaking on the Follow the Sun Bus

Our first tour stop was the Enel North America Lake Pulaski site. This site combines solar, pollinators, an apiary, and sheep grazing. Jesse Puckett and Eric Bjorklund from Enel North America gave a safety briefing, an overview of the site, and described Enel’s agrisolar work around the world. 

Jesse Puckett and Eric Bjorklund of Enel North America Speaking at Lake Pulaski

Jesse then passed it off to Jake Janski and Audrey Lomax from Minnesota Native Landscapes (MNL), who described the plant and sheep grazing management process and studies at the site.

Jake Janski Describing MNL Work at the Lake Pulaski Site

Solar Grazing Sheep at Lake Pulaski

Audrey Lomax Fielding Questions from Tour Attendees

Jordan Macknick, James McCall, Abbi Brown, Haley Paterson, and Benjamin Frank from NREL talked about their InSPIRE project work and their robust studies of the Lake Pulaski site and the relation to other InSPIRE research projects around the country.

Jordan Macknick and James McCall Describing NREL’s InSPIRE Research and Work
Iara Lacher Taking Photos of Pollinators

Dustin Vanasse from Bare Honey then treated the group to an experience of a lifetime.  He brought six beekeeper suits and let the group interact with an active hive on the site.

Follow the Sun Tour Attendee with a Close-Up View of the Hive

Beekeeping with Dustin Vanasse of Bare Honey at Lake Pulaski

While we took turns in the bee suits, John Vaughn from the Minnesota Rural Renewable Energy Alliance talked about their work. After removing the beekeeper suits, we boarded the bus and heard from Wendy Caldwell from Monarch Joint Venture about the positive impacts of solar pollinator habitat on the monarch population while we enjoyed Bare Honey solar grown honey sticks.

Wendy Caldwell Capturing Photos of Monarch Caterpillars

Our second stop took us to the US Solar’s Big Lake facility. We had so much help from Rob Schultz on navigating to these sites, and I am so grateful he was there to guide us through the day.

Rob Schultz Discussing How to Help Us Find the Next Tour Stop

At Big Lake, we heard from Colleen Hollinger from Natural Resource Services and Peter Schmitt and Ross Abbey from US Solar.

Colleen Hollinger Describing AgriSolar Impacts to the Surrounding Ecosystem 

Back on the bus, Dan Shaw talked with us about his work with pollinators and solar, including his work developing the pollinator scorecard system.

Dan Shaw and Wendy Caldwell at the US Solar Big Lake Site

We then stopped at the at the Connexus’ Solar + Storage Site (link to case study), where our partner Rob Davis talked about Connexus’ work in agrisolar and sustainable energy. Heidi Hartman from Argonne National Lab discussed her research into the ecosystem services at the site and brought a group of researchers with her to collect data from the site.

Rob Davis Describing Connexus Energy’s Solar + Storage Site

Heidi Hartmann Describing Argonne Ecosystem Services Research at the Connexus Site

Group Photo at the Connexus Solar Plus Storage Site

We finished the day with a Solar Farm to Table Sampler, sponsored by Enel North America, through a grant to the National Center for Appropriate Technology’s AgriSolar Education program. This event featured food and beverages grown at solar farms and was held at Connexus Energy Headquarters.

Chefs Erin Lucas and Mateo Mackbee created a wonderful menu of delicious food, including spicy braised lamb flat bread with chiltepin peppers from the Biosphere agrisolar site, and lamb from Cannon Valley Graziers and Minnesota Native Landscapes Minnesota; a solar greens salad with solar-grown honey and sweet grass vinaigrette featuring honey from Connexus and Enel solar in Minnesota and greens and sweet grass from NREL and Colorado solar; saffron vegetable skewers featuring saffron from Vermont solar; vegetables from NREL and Colorado solar; Minnesota solar-grown peach and plum cobbler, featuring fruit from Enel solar in Minnesota. 

Chef’s Erin Lucas and Mateo MackBee
Delicious Solar-grown Food at the Solar Sampler Event

The chefs cooked the food with solar power, including a solar generator and a solar-powered electric truck, powered by the Connexus Headquarters solar array. For drinks, solar-grown honey sweetened the lemonade and Rob Davis’s signature cocktail, Everything but the Stinger, featuring Clif Family’s solar-grown honey ginger syrup. Invictus Brewing treated the group to their 1.7 Million Megawatts British Summer Ale, made with solar-grown honey.

The sampler was an excellent networking opportunity and chance to discuss what we learned and witnessed through the day. There was so much excitement about future projects and partnerships and plans. The hum of enthusiasm was palpable. 

Networking at the Follow the Sun Tour

While folks connected, we heard from Greg Ridderbush, Connexus Energy’s CEO, about their commitment to agrivoltaics and sustainable energy and the great work performed by the company. We then heard again from Jesse Puckett and from Rob Davis, and I wrapped up the day with a hearty toast to our AgriSolar Clearinghouse community. 

Connexus Energy CEO Greg Ridderbush

As I milled around, I watched the AgriSolar network strengthen and expand. Folks made plans, dreamed up future events, talked about partnerships, exchanged business cards, and enjoyed each other’s company. As our stakeholder Lucy Stolzenberg said, the only way to make the event better would be to have another!

A Toast with Invictus Brewing’s 1.7 Million Megawatts British Summer Ale

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!

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.

Ridge to Reefs staff, including Emma Verlinden, Phal Mantha, and Paul Sturm

Hawai’i has a deep-rooted agricultural history, and today there are more than 7,000 individual farms in operation. Due to a confluence of factors, agricultural producers in Hawai’i face a variety of significant challenges when compared with their mainland counterparts. High costs associated with land, labor, and inputs, as well as relative geographic isolation from large markets in the continental United States are notable contributing factors. Other challenges in the form of habitat modifying invasive species, degraded agricultural infrastructure, and legacy agricultural problems continue to impact the agricultural viability and competitiveness of Hawaiian producers today. Furthermore, electricity costs in the Hawai’i are among the highest in the United States with residential consumers paying an average of about 37 cents a kilowatt-hour (UH-HERO ). In 2015, the State of Hawai’i mandated that by the year 2045, 100% of the state’s electricity must be generated by renewable energy sources. Electric companies on the islands have made efforts to increase their renewable energy portfolio, such as energy provider Hawaiian Electric, which increased its renewable sources to 38.4% in the past few years. Though a variety of challenges exist, widespread adoption of regionally adapted agrisolar models could provide Hawaiian agricultural producers, landholders, and communities with significant benefits. A closer look at recent solar developments and related progress (or lack of progress in some cases) in Hawaii may help to paint a clearer picture of the opportunities and challenges that are associated with adoption of these technologies.

The Wailua Egg Solar + Sheep Farm is a 6 MW Solar + battery project that will host 1 million cage free chickens spread across 11 buildings and raise 200 sheep a year for Oahu markets and restaurants. The facility is completely grid independent with solar arrays incorporated into cage free shelters and the resulting poultry litter being converted into biochar by gasifiers. Wastewater and process water are recycled for irrigation purposes and are also land applied to designated leach fields located on site.

Figure 1: Aerial image of Wailua Egg Solar Sheep Farm’s existing solar poultry houses. The proposed expansion of this solar farm and sheep grazing operations have faced some local opposition due to a variety of concerns.

Figure 2: Aerial view of the farm’s poultry litter gasifier, which converts poultry litter into biochar, a valuable soil amendment.

Figure 2: Aerial view of the farm’s poultry litter gasifier, which converts poultry litter into biochar, a valuable soil amendment.

Though there are clear cost, food security, and environmental benefits associated with this operation, concerns have been raised about upcoming expansions (specifically, the proposed solar farm and sheep grazing areas). In Hawai’i, IAL (Important Agricultural Lands) designation prohibits all uses except what is defined as “agricultural use.” This has the potential to limit the locations where photovoltaic and agrisolar projects can be developed. This criticism also serves to highlight a key issue surrounding these projects in the state: the “food vs. Fuel” debate and the use of prime agricultural lands for energy generation. This is one reason this project has run into local opposition, with some citizens and residents reporting that they are concerned over the use of fallow “prime agricultural lands” for power generation. Though these are valid concerns, integrating grazing practices and other forms of agriculture with photovoltaic based power generation may help to balance these concerns and simultaneously produce power and food on the lands. According to a recent white paper published by the Ulupono Initiative citing University of Hawai’i researcher Dr. Matthias Fripp’s work, a viable solution may be to utilize sloped lands for these developments so that they do not use up prime agricultural lands. Specifically, this publication notes that “While solar developers may be apprehensive to developing on higher-sloped lands…a willingness to develop solar facilities on sites with <20% slope, at a slightly higher per project cost, will allow for most, if not all, of Oahu’s agricultural lands to be protected.”

Other challenges to solar developments in the state include the Jones Act, which can limit procurement options, resulting in high material and shipping costs. Furthermore, Land Study Bureau Classifications classifying farmland from most productive to least productive can limit areas that can be used for such projects. Though challenges to widespread adoption of agrisolar technologies in Hawai’i still exist, there is strong potential for numerous co-benefits both at the utility and individual farm scale.

Figure 3: Integrating grazing sheep with solar developments in the Hawai’i has proven to be an effective and low cost solution to managing agressive invasive grasses such as Guinea Grass and Cane Grass which can be the dominant land cover on many agricultural lands in the state.

Even at the individual farm scale, integration of photovoltaics with agricultural operations can facilitate a diverse array of use cases and has the potential to yield numerous benefits for local stakeholders. For example, photovoltaics integrated with refrigeration systems can provide robust, grid-independent cold storage and energy for critical operations and post-harvest processing facilities.

Figure 4: Th is breadfruit farm, nursery, and value-added product manufacturing facility for breadfruit flour in Puerto Rico is powered entirely by solar power. This model can also be applied in Hawa’ii and has the potential to provide farmers with robust grid independent post-harvest processing capabilites.

Furthermore, solar irrigation, water filtration, native species, and pollinator habitat can all be integrated with these solutions in a regionally adapted and relevant manner. Specifically, adoption of agrisolar technologies can provide agricultural practitioners with the opportunity to generate additional income, reduce operational and maintenance costs, decrease water consumption, utilize marginal agricultural lands, and protect the quality of their soil. Financially, these solutions may allow them to generate additional income by selling electricity from their lands, leasing land to solar developers, and powering their own farm equipment. The cost of imported energy sources, such as petroleum and coal, to Hawai’i is approximately – three to four times higher than on the mainland and decreasing the need for these sources by constructing solar modules on agricultural land could save farmers a great deal.

In fact, a study in 2012 showed that the standard solar construction in Hawai’i paid for itself in only four years and generated a profit of over four times the initial cost over the course of its life (8 ). Farmers can also decrease the cost of irrigation on their lands. There are currently solar modules that are being used to fully power irrigation systems on farmland in Africa, South America, and India (1). The significance of this is great, as roughly 85% of all water use globally is for irrigation systems, and Hawai’i is actively experiencing difficulty with water shortages and seeking innovative solutions for increasing water availability and reuse. Plants and crops that are grown underneath the shade of solar panels require less water than when exposed to full sunlight. This is due to the fact that plants in full sunlight reach their light saturation point earlier in the day, after which they do not grow more or photosynthesize more, they simply require even greater amounts of water to process the levels of sunlight.

Hawai’i also has an extensive history of monocultural plantation agriculture that has left a lasting mark on the quality of the soil where farmers are growing crops today, exemplifying what are known as legacy agricultural issues. In some areas, nutrients and organic matter from the soil have been heavily overdrawn, forcing farmers to rely on expensive imported fertilizers to maintain their production. Over the course of these decades, excessive tilling of the earth and subsequent depletion of organic matter has led to erosion, soil loss, and pollution to sensitive coastal ecosystems. There are also previously used agricultural roads that often are no longer actively managed, which combined with erosion are leading to ongoing pollution and sediment export from these areas. One study found that solar installations can provide a recovery period for overused soil and actually increase the value of agricultural land over time by revitalizing soil over the course of the panels’ 20- to 25-year life.

Another issue facing agricultural producers in Hawai’i is the undulating topography of the islands that makes much of their land unusable for general agricultural practices. By relegating areas of steep topography for solar panel installation, farmers can increase the amount of usable space on their farms. When combined with grazing animals such as sheep, the productivity of these panels is increased, and the costs of maintenance for the panels is greatly reduced. An analysis of maintenance costs by Nexamp showed that solar grazing saved the company 19% on flat ground, but where panels were built on steep ledges and grazed under, they saved 38% (2). Another benefit to agricultural land use in the state of Hawai’i that could benefit from agrisolar practices would allow farmers to make use of dry, arid lands, such as those seen on windward slopes of the islands or the Kaupo region of Maui. Dr. Barron-Gifford at the University of Arizona found that dry land crops yielded substantially greater production when grown under solar panels: Chiltepin pepper plants yielded three times as much fruit, tomatoes two times as much, and all were seen to require less water than without panel coverage (3). Therefore, combining dryland agriculture with novel agrisolar solutions may prove to have numerous advantages over using either one of these strategies on their own.

Benefits such as these could significantly increase agricultural productivity throughout the Hawai’ian Islands, creating a more sustainable agricultural economy and giving local families a greater opportunity to save money and to access locally grown foods. There are many government programs now that can assist farmers in making the transition from general agriculture to agrisolar, and with the pressing need for sustainability, this may present as one of the most important solutions for Hawai’i’s ongoing economic and environmental difficulties.

1. 2020 Guide to Hawaii Solar Panels I Incentives, Rebates, and Tax Credits
2. Lynn Freehill-Maye, 2020, A New Vision for Farming: Chickens, Sheep, and … Solar Panels, Christian Science Monitor,
3. ASGA, 2020, Utility Dive Does a Deep Dive on Solar Grazing,
4. Solar Energy Technologies Office, Farmer’s Guide to Going Solar, Depoartment of Energy,
5. Sustainable Farm Agrivoltaic, Oregon State University,
6. Dr. Matthias Fripp, 2022, White Paper: Switching the paradigm, Ulupono Initiative,
7. Taylor Freitas, 2022, Hawaii Solar Panels: Pricing and Incentives, Save On Energy,
8. Solar Power in Hawaii, Wikipedia,
9. Thomas Heaton, 2022, Hawaii Needs Good Soil To Grow More Food. Here’s How That Can Happen, Honolulu Civil Beat,
10. Maui News, 2022, Hawaii Electric hits 38% renewable energy in 2021; Maui County at 50%,
11. USDA, 2017, Census of Agriculture State Profile,