This PhD dissertation addresses four primary questions: 1.) To what extent is plant-available radiation reduced by solar panels of a photovoltaic system? 2.) How does this effect parameters of aerial and soil climate? 3.) How do the cultivated crops respond to the altered cropping conditions with regard to plant growth and development? 4.) What consequences does this have regarding the yields and the chemical composition of the investigated crop-species? A field experiment in which grass clover, potatoes, celery, and winter wheat were planted under a photovoltaic facility in Southwest Germany was conducted to answer these questions.
Tag Archive for: Agrivoltaics
This guide, developed in Germany by Fraunhofer, provides information on the potential of agrivoltaics, including the latest technologies and regulatory frameworks in this area. It also offers practical tips on how agrivoltaics can be used by farmers, municipalities and companies.
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.
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 researchers in this study aimed to simulate crop yields for paddy rice, barley, and soybeans grown under photovoltaic panels with an eye on reaching suitable agricultural productivity for the energy and food nexus coexistence. They also applied a geospatial crop simulation modeling system to stimulate the regional variations in crop yield according to solar radiation reduction scenarios.
This study evaluates green bean cultivation inside greenhouses with photovoltaic (PV) panels on the roof. Researchers found that the beans adapted to the change in shading by relocating more resources to the stems and leaves. As a result, average yield decreased compared to that of a conventional greenhouse. However, an economic trade-off between energy and crop yield can be achieved with a panel coverage of 10%. The research also provides an experimental framework that could be replicated and used as a decision support tool to identify other crops suitable for solar greenhouse cultivation.
Farmers in France are Beginning to Combine Solar Panels and Crops
“In the Haute-Saône region, in the northeastern part of the country, an experiment is being conducted by solar-energy company TSE. It is hoping to find out whether solar energy can be generated without hindering large-scale cereal crops. Previous attempts to experiment with agrivoltaics have been through smaller-scale projects. But, keen to see if it can thrive on an industrial level, 5,500 solar panels are being spread over this farm in the commune town of Amance by TSE.” – Euronews
Solar Grazing Event Helps Kentucky Students Learn about Agrisolar
“The event was made possible through a partnership between the Kentucky Sheep and Goat Development Office, LG&E/KU, University of Kentucky, Ohio State University, and solar development company Lightsource bp. Students learned about solar technology, seed mix establishment and meeting nutritional needs in solar grazing. Additionally, the release said students were able to tour the LG&E/KU E.W. Brown Generating Station’s solar array in Mercer County.” – The News Enterprise
Cornell Researcher Hosts EarthTalks Agrisolar Series
“Niko Kochendoerfer, a postdoctoral fellow in animal sciences at Cornell University, will deliver the talk ‘Effect of sheep stocking rate on ecosystem parameters in ground-mounted solar arrays’ at 4 p.m. on Monday, Nov. 14. The talk, which is free and open to the public, takes place in 112 Walker Building on the University Park campus and via Zoom.” – PSU
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.
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.
This article examines current literature regarding the application of shading systems alongside crop production, with a focus on photovoltaic panels and greenhouse studies. After reviewing 113 articles, the authors conclude that most studies do justify the co-location of photovoltaic panels and crops. However, more crop-specific research is necessary to determine the optimum percentage of panels that will not reduce agriculture production.
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.
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 (solar-sharing.org) 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.
This project developed a new racking/mounting system combined with a new specialized solar panel for low-cost implementation in a hybrid high tunnel greenhouse. The project successfully demonstrated that high value crops can successfully be combined with solar electricity production, even resulting in improvements to yields for certain crops.
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