Tag Archive for: Agrivoltaics

This study presents data for a techno-economic price-performance ratio calculation retrieved from an inter- and transdisciplinary agriphotovoltaic case study in Germany.

The Maine Department of Agriculture, Conservation, and Forestry presents this technical guide regarding the siting of utility-scale solar projects with consideration for valuable agricultural land, forest resources, and rare or unique natural areas. The guide is intended to provide practical information for those considering solar development on their property, as well as planning important preconstruction, construction, and post-construction/decommissioning activities.

This paper is an analysis of three different agrivoltaic configurations: static with optimal tilt, vertically-mounted bifacial, and single-axis horizontal tracking. A model is also developed to calculate the shadowing losses on the PV panels along with the reduced solar irradiation reaching the area under them for different PV capacity densities.

Below is a compressed version of the article – click here to view the original version.

This article posits that in order to optimize agrivoltaic systems for crop growth, energy pathways must be characterized. While solar panels shade crops, they also emit longwave radiation and partially block the ground from downwelling longwave radiation. The authors suggest that a deeper understanding of the spatial variation in incoming energy would enable controlled allocation of energy in the design of agrivoltaic systems. This paper also presents a model to quantify the downwelling longwave energy at the ground surface in an agrivoltaic array and demonstrates that longwave energy should not be neglected when considering a full energy balance on the soil under solar panels.

When installing photovoltaic panels on agricultural land, one of the most important aspects to consider are the effects of the shadows of the panels on the ground. This study presents a valid methodology to estimate the distribution of solar irradiance in agrivoltaic installations as a function of the photovoltaic installation geometry and the levels of diffuse and direct solar irradiance incident on the crop land.

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.

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.

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 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.