Tag Archive for: AgriSolar

Case Study: Oregon Agrivoltaic Research Facility

Cantaloupe melons growing between rows of solar panels. 

By Anna Richmond-Mueller, NCAT Energy Analyst

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Just south of Portland, Oregon, researchers with Oregon State University (OSU) are putting agrisolar principles to the test at the Oregon Agrivoltaic Research Facility. The site is located at the Noth Willamette Research and Extension Center (NWREC) and serves as host to OSU’s ongoing agrivoltaic research under the leadership of Dr. Chad Higgins. The numerous studies conducted on the site will contribute to advancements in multiple fields, including plant physiology, water usage, and soil health, all while producing power for Oregon citizens through a community solar program.  

While agrivoltaics research has picked up in recent years, a large number of the sites being studied were not originally built with agrisolar pursuits in mind. Although it’s entirely possible to successfully integrate agricultural practices into an existing solar array, using only these sites for research lessens the opportunity to discover agrivoltaic’s full potential. With the Oregon Agrivoltaic Research Facility, Dr. Higgins and OSU flipped the narrative by instead asking: what if a solar site was designed to maximize agricultural production?  

The OSU team felt it was important to approach the project from the perspective of a farmer looking to add panels into their current operations. With that goal in mind, the decision was made to design an array that wouldn’t necessitate the purchase of specialized farming equipment capable of working amongst the panels. Instead, they used NWREC’s current tractor to determine how far apart the bifacial panels needed to be spaced and chose a racking system that can tilt to a vertical position on command.  

A row of dry farmed crops between solar panels. 

Once again approaching the project as a farmer might, Dr. Higgins and his team chose to fund the project through loans, investors, and grants rather than having the university entirely foot the bill. The team partnered with Oregon Clean Power Cooperative (OCPC), who financed the project and maintain ownership over the site. OSU contributed about 5% of the necessary funds, and OCPC’s community investment model provided the framework for local investors to contribute as well. The project also received grants from both Portland General Electric and the Roundhouse Foundation, which provided funding for on-site NWREC staff, research, materials, and construction costs. OSU anticipates the project will pay for itself in about 10 years.  

In addition to providing space for agrisolar research, the site also serves as a community solar operation with Oregon Clean Power Cooperative. OCPC was heavily involved in the project from the beginning, working with Dr. Higgins to design the system and purchase the equipment in the midst of a supply chain crisis during the pandemic. Thanks to the dedication of both parties, construction on the 5-acre, 320-kW site wrapped up in the fall of 2022, and it began producing power the following April. The site is OCPC’s first community solar project for Portland General Electric customers. Currently, OSU buys some of the power from the array, and the remaining is purchased by a local church, synagogue, and area residents, including low-income households who receive the power at a 50% discount. The partnership between OCPC and OSU has been so successful that OCPC is in the process of developing two more sites for OSU’s agrivoltaic research in the state.

Melon crop area being monitored for detailed data collection. 

Although the Oregon Agrivoltaic Research Facility is only in its first year of operation, extensive studies are already underway onsite. By the end of fall 2023, a study on soil compaction from installation will be complete, as well as an investigation into soil health in bare ground versus agrivoltaic spaces. OSU is also investing in long-term research, with a 20-year study on pollinators beginning in fall 2023. More extensive soil-quality projects will also start in the fall, looking to determine how an agrisolar system impacts soil health markers over 20 or more years. Sheep will graze on the site for part of the year, allowing for research on seasonal forage and sheep nutrition.  

Dr. Chad Higgins and Follow the Sun tour attendees behind Argonne National Lab’s wildlife monitoring camera. 

Nestled in the center of the array is a grassy row with a camera set at one end, seemingly at odds with the rows of plants surrounding it. This unassuming row is actually the location of two important studies, one focused on wildlife and the other on grass growth as a proxy for crop productivity. Argonne National Laboratory monitors the camera for wildlife that wander into the array, concentrating specifically on observing how the bird population interacts with the solar array. The grass is just one of several plots around the world included in an ongoing study by the United Nations, which is dedicated to predicting how certain crops will grow in a given environment. NWREC is home to another one of these plots, located outside of the array, and OSU team will analyze how the two onsite plots compare. This will give them insight into how a number of crops are likely to grow within the array without having to actually cultivate each plant.  

In September 2023, the AgriSolar Clearinghouse’s Follow the Sun tour had the opportunity to join Dr. Higgins in Oregon and see the OSU team’s crop research in action. The researchers chose to grow their crops using a technique called “dry farming,” which relies on soil moisture and rainfall to water the plants rather than irrigation. Agrivoltaics pairs particularly well with dry farming because the shade from the solar panels significantly reduces soil moisture loss. Several varieties of squash, tomatoes, melons, hemp, and hydrangeas were successfully growing between the panels, and plans to add blueberries in the coming months were on the docket, as well. More than 75 people signed up to attend the tour and had the opportunity to listen to Dr. Higgins discuss the research facility, scalability of the project, financial considerations, and initial observations of the plants growing within the array.  

The Oregon Agrivoltaic Research Facility’s commitment to embracing dual-use agriculture is truly inspiring. In addition to the research already in progress, there is an entire row of panels dedicated to experiential learning, the development of lesson plans, and opportunities for students. OSU’s clear investment in both current and future leaders in the agrisolar world leaves little doubt that the site will become a major contributor to the ever-growing body of agrivoltaic knowledge. 

Hemp plants (left) and delicata squash (right) growing within the array. 

Photo credit: NCAT

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Agrivoltaics Mitigate Drought Effects in Winter Wheat

The aim of this study was to assess the effects via carbon isotopic composition in grains, as well as the grain yield of winter wheat in an agrivoltaic system in Southwest Germany.

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Harvest the Sun — Twice

Vines growing among solar arrays. Photo: NCAT

By Brian Naughton, Co-Founder Circle Two, LLC. This article was first published in the NM Healthy Soil blog.

The sun provides abundant energy here in New Mexico, something I’ve appreciated professionally and personally since moving here ten years ago to work on renewable energy. The sun can also be a bit much at times as seen in my rather disappointing tomato patch this year. I’ve always enjoyed gardening as a hobby, but a few years ago I decided to step things up a bit by volunteering at the Rio Grande Community Farm located on the Los Poblanos Open Space in the North Valley of Albuquerque. I’ve learned so much from the community that gathers and works there about every aspect of growing food from soil health, irrigation methods, tools from small to big, and climate-controlled greenhouses to the changing climate of the open field.

One of my first days volunteering at the farm I noticed a stack of solar panels in the barn and began to brainstorm ways my renewable energy background and interest in growing food might work together. In the course of my research I came across the term agrisolar. Agrisolar, or agrivoltaics as it is sometimes called, is simply the co-location of solar power production with appropriate agricultural land use. This definition comes from the National Center for Appropriate Technology (NCAT), hosts of the AgriSolar Clearinghouse, a website for all stakeholders who are interested in finding trusted agrisolar information, funding sources, events, and more. 

As I’ve learned, there are multiple potential benefits of pairing solar and agriculture. As interest in both renewable energy and sustainable agriculture grows, agrisolar has the potential to meet both needs. The benefits include producing food, conserving ecosystems, creating renewable energy, increasing pollinator habitat, and maximizing farm revenue. In our arid Southwest landscape, researchers at the University of Arizona have found the microenvironment among the solar panels can increase humidity, decrease daytime temperatures, and increase nighttime temperatures, all of which can increase the efficiency of crop production and solar electricity generation in a symbiotic relationship.

Tomatoes growing in an agrivoltaic setting. Photo: NCAT

I find the broader connections between energy and food quite interesting and important. Sunlight is the primary energy source that keeps our living ecosystem, and our human gizmos, moving. Plants absorb the daily flows of sunlight to convert carbon dioxide in the air into biomass above and below ground. Our human systems largely do the opposite, combusting stocks of solar energy in the form of fossil fuels in the ground and turning them into carbon dioxide in the air, with all the resulting impacts we’ve come to know too well. Our domesticated crops turn out, perhaps unsurprisingly, to be a bit of a mix of energy sources.

Researchers at the University of Michigan have compiled data from multiple sources to produce some eye-opening infographics on energy use in the US food system. The biggest takeaway for me is that on average it requires 14 times the energy inputs for each calorie we consume, and the majority of that input is still fossil fuels. Perhaps agrisolar projects can help shift that statistic towards something more sustainable, but there are some knowledge gaps about how best to deploy this technology.

Agrisolar in New Mexico

One of the six soil health principles promoted by New Mexico Healthy Soil and others is to know your context. This applies equally well to agrisolar projects and the need for location-specific knowledge. While some agrisolar knowledge and practice is universal, much of it is location-specific. Fortunately, there are a few nascent efforts in New Mexico beginning to explore agrisolar applications and develop best practices for our state. I’ve chosen a few to highlight that I’m aware of, but I’m sure there are many more people and organizations that are experimenting with this approach that I have not yet learned of. 

New Mexico State University

Researchers at New Mexico State University just completed their first year investigating New Mexico green chile production under partial agrivoltaics shading at the Leyendecker Plant Science Research Center near Las Cruces. Drs. Marisa Thompson, Stephanie Walker, Olga Lavrova, and Israel Joukhadar lead the project that is supported by the New Mexico Department of Agriculture’s Specialty Crop Block Grant program. Mariela Estrada is a graduate student on the project helping to coordinate the field trial and gather data, which is currently being analyzed. The project is exploring the effects of integrating solar panels into vegetable production fields, with a particular focus on the impact on disease, plant growth, and overall yield. This innovative integration of technology into agricultural fields has the potential to offer dual benefit to New Mexico producers, protecting their crops from the region’s hot and arid climate while simultaneously generating additional income through renewable energy production. The researchers are considering additional crops they could study in the coming years.

Chiles growing on an agrisolar research site at New Mexico State University. Photo: Israel Joukhadar

USDA Agricultural Research Service

Another agrivoltaics research project in the Las Cruces area is being led by the USDA’s Agricultural Research Service. Brandon Bestelmeyer from the Range Management Research location and Derek Whitelock from the Southwest Cotton Ginning Research Laboratory are collaborating on a project titled “Sustainable Multi-functional Agricultural and Energy Systems for Arid Environments.” The project aims to develop optimized agrivoltaic designs for rangeland, crops, and processing facilities and to build accompanying decision support tools including economic and life-cycle assessments so farmers and ranchers can make informed decisions about their operations. The project will be a highly collaborative effort engaging with multiple stakeholders. University partners will support experiments in photovoltaic installations exploring crop and soil types common to Southwestern ecosystems at agricultural research centers and postharvest processors. Government agencies and agricultural stakeholders managing land on which renewable energy is being developed are also envisioned as project partners. The project just kicked off in 2023 and will begin by defining knowledge gaps about potential agrivoltaic co-benefits and challenges to determine priorities for subsequent research in the region.

Los Alamos National Laboratory

One of the first agrivoltaics projects I learned about was in the El Rito area led by Los Alamos National Laboratory researcher Sanna Sevanto to support Trollworks, a biochar production equipment manufacturer located in Santa Clara, NM. Funded through the New Mexico Small Business Assistance Program, the researchers tested the effects of biochar on plant growth in an agrivoltaics setting at the solar installation located at Northern New Mexico College’s El Rito campus. Growth and productivity of tomato and Swiss chard was compared on plots where originally non-arable soil was amended to crop growth by incorporating compost and a compost-biochar mixture to the original soil under and next to the solar panels (see photo). The 1.5-megawatt solar installation itself was constructed in 2019 under a partnership between Northern New Mexico College, Kit Carson Electric Cooperative (KCEC), and Guzman Energy. The array helps to transition not only the college, but also the entire KCEC membership and communities west of the Rio Grande served by KCEC toward achieving 100% daytime solar power.

SunShare

Community solar offers a particularly exciting opportunity for agrivoltaics in New Mexico. Signed into law in 2021, the program administrator awarded the first 200 megawatts of capacity to multiple solar developers to construct projects up to 5 megawatts each that will offer subscriptions to customers of the three investor-owned utilities in the state. One of those developers is SunShare, a developer of community solar installations founded in 2011. In addition to providing workforce development opportunities, lease payments to local landowners, and electric bill discounts to low-income subscribers, SunShare will be working with New Mexico Healthy Soil Working Group to incorporate agrivoltaic design concepts into their New Mexico projects. SunShare already has some demonstrated experience with agrisolar on a project in Minnesota working with local farmers on vegetable production and an apiary located within the solar panel rows (see Minnesota Farm Guide: Agrivoltaics—Solar plus farm production is gaining ground).

Sandia National Laboratories

The final agrivoltaics project I’d like to highlight is from a diverse team led by Dr. Ken Armijo at Sandia National Laboratories with partners at SkySun, University of New Mexico, Jemez Mountain Electric Cooperative, Rio Grande Community Farm, and my own company, Circle Two. The project started this fall and will explore a novel solar technology developed by Skysun and Sandia over the next two years including laboratory testing at Sandia, field testing at Rio Grande Community Farm and assessing the commercial potential within the Jemez Mountain Electric Cooperative service area. The unique design of the photovoltaic system (see image) will allow improved crop cultivation access with tractors and personnel along with more efficient operations and maintenance over commercially available fixed-framed agrivoltaics installations. The agrivoltaics system will be connected to a battery storage and control system forming a microgrid to power on-site loads including an electric tractor and irrigation pumps. This project brings my agrivoltaics journey full circle starting with that stack of solar panels in the barn and now exploring the potential benefits of combining solar energy and crops in the field at the nearby fields at Rio Grande Community Farm.

Click here to view the original post and photos on the New Mexico Healthy Soil blog.

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Open-Source Vertical Swinging Wood-Based Solar Photovoltaic Racking Systems

This study discusses the development of a wood-based PV vertical racking design, created to help overcome cost barriers present with commercially available vertical racks. This design is constructed with domestic renewable and sustainable materials, buildable by the average farmer, has a 25-year lifetime that aligns with most PV warranties, and follows Canadian building codes to weather high wind speeds and heavy snow loads.

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New Mexico’s Chile Crop Is Hot on Agrivoltaics 

Chile plants within shade of photovoltaic panels (right) and chile plants cultivated in full sun (left). 

Written for the AgriSolar Clearinghouse by Israel Joukhadar and Stephanie Walker, New Mexico State University  

New Mexico has tremendous potential in solar energy production thanks to its consistently sunny weather and high levels of solar irradiance. Presently, the state’s solar market holds a value of $3.2 billion with significant room for expansion. As stakeholders express increasing interest, they are discovering a trend observed in several other states: some of the most favorable locations for extensive solar developments are within agricultural production fields. The concept of integrating photovoltaic (PV) panels into these fields, known as agrivoltaics, has gathered attention and investment. 

Chile (Capsicum annuum L.) holds significant importance as a vegetable crop in New Mexico. Chile was initially brought to New Mexico more than 400 years ago and it has been continuously cultivated throughout the state since that time. Its cultivation and trade hold immense cultural importance to New Mexico, while simultaneously contributing to the state’s economy by providing income and employment to farmers and through supporting industries. Producers in the state harvest both red and green crops. Green fruit are full size, but physiologically immature, while red fruit are physiologically mature. The question of “Red or Green?” is the official state question, symbolizing the preference for either red or green chile and showcasing cultural attachment to this beloved crop.    

New Mexico State University is home to the longest running chile pepper breeding and genetics program in the world. This initiative traces its roots back to 1888, when it was initiated at the New Mexico College of Agricultural and Mechanic Arts, the precursor to NMSU, under the guidance of Fabián García, the first director of the Agriculture Experiment Station. Dr. García embarked on a journey of breeding and selection that eventually led to the development of New Mexico pod-type chile, which is now globally recognized as New Mexico type (NM) or Hatch chile. Over the course of its existence, the NMSU chile breeding program has introduced more than 50 distinct chile varieties.   

New Mexico is the largest chile producer in the US; however, since peak production in the early 1990s, there has been a reduction in acreage. The decline was the result of various factors including labor shortages, increased international competition, and heightened disease pressure. Increasingly, heat stress and irrigation availability are adversely impacting the crop. To protect and sustain NM chile production, it is imperative to implement a multifaceted approach to address various challenges encountered by producers throughout the production and post-harvest processes. More than a decade ago, research scientists at NMSU initiated efforts to develop mechanized harvesting solutions, aiming to alleviate the challenges posed by labor shortages. Now, those very research scientists are joining the agrivoltaics research movement. Their goal is to address additional challenges faced by NM chile producers. They are exploring co-location of PV panels within agricultural fields as a potential strategy to address certain challenges. Thanks to a grant from the New Mexico Department of Agriculture awarded to Drs. Thompson, Walker, and Lavrova, research has begun in evaluating how solar panel shading affects the movement of beet leafhoppers. These leafhoppers are vectors for the Beet Curly Top Virus (BCTV), a significant disease impacting the state’s signature chile pepper crops.  

Infection with BCTV results in various symptoms including stunted growth, curling and twisting of leaves, and the production of small unmarketable fruit. The specific symptoms may vary based on the plant’s growth stage when it becomes infected. Previous research has shown that beet leafhoppers tend to avoid shaded areas and exhibit peak activity between 10 am and 2 pm. The concept was to leverage the shade provided by solar panels as a means of deterring beet leafhoppers with the goal of reducing the incidence rate of the BCTV while not adversely impacting yields of chile peppers grown under the PV panels. This research was conducted at NMSU’s Leyendecker Plant Science Research Center, located near Las Cruces, NM. Before the first season, four fixed PV panels were installed, adhering to low-impact installation guidelines to minimize land disturbance. The panels were facing east. Although this is not the most efficient orientation for energy generation, it was ideal to shade the chile between 10 am to 2 pm. Then ‘NuMex Odyssey,’ a green chile variety developed for mechanical harvest, was transplanted into the field in the beginning of May and harvested in mid-August 2023. After completing the initial field season, many valuable insights were gained that will be useful for interested NM stakeholders. Preliminary results indicate potential yield and BCTV prevention benefits to chile plants cultivated under the shade of PV panels, but a second year of data is necessary to draw more specific conclusions. 

Romaine lettuce harvested from partially shaded area under photovoltaic panels

Danise Coon, Mariela Estrada, Isaac Medrano, and Jannatul Afroze (left to right), measuring harvested lettuce. 

Traditionally, chile is cultivated within a crop rotation strategy to mitigate soil-borne diseases. To mimic this rotation cycle, romaine lettuce (Lactuca sativa) was planted immediately after the chile crop in the beginning of September and harvested by the end of October 2023. During this transition, the orientation of the solar panels was modified from an east-facing direction to a south-facing one. The shift in panel orientation served two primary purposes: 1) During the chile growing season, shading between 10 am and 2 pm was essential to deter beetleaf hoppers. As the crop changed to romaine lettuce, this shade was no longer necessary and 2) With the advent of cooler mornings in September and October, increasing the morning sunlight became imperative to warm the plants effectively. This transition prompted a crucial consideration in the fundamental objective of each agrivoltaics site. Should it aim to maximize energy generation or crop production?  

Our present objectives include conducting a repeat of both these studies next year and sharing research outcomes with the public. Alongside our ongoing research, we are actively pursuing funding to broaden our investigations. This expansion will encompass flavor and nutrient analysis of the crops, various vegetable types and varieties, optimal irrigation designs, as well as further explorations into pest and diseases with agrivoltaic systems in New Mexico.  

Photos courtesy of Israel Joukhadar. 

AgriSolar News Roundup: ENEL Develops Agrisolar System, Agrisolar Research in Iowa, New Chinese Agrisolar Design 

ENEL and ENEA Develop Microalgae Agrisolar System  

“ENEA and Enel have developed an ‘algovoltaic’ system to cultivate high-value microalgae, ranging from €100 ($106.19)/kg to €600/kg for pharmaceutical uses or cosmetic purposes. This is possible due to the integration of a fully automated cultivation system with a 7-kW solar array. 

The system allows the cultivation of microalgae with a high commercial value, from €100/kg to €600/kg for pharmaceutical or cosmetic use, through a fully automated cultivation system integrated with the solar array.” – PV Magazine 

Iowa State University Develops Agrisolar Project to Study Land Use 
 
“Iowa State University (ISU) is embarking on a research project to explore the combination of crops and solar power. The Alliant Solar Farm at Iowa State University is a groundbreaking agrivoltaics research project merging solar power generation and agriculture to study how best to optimize land use while providing local community benefits. The array was inaugurated on Thursday, October 19th with a ribbon-cutting ceremony.” – prnewswire 

New Chinese Agrisolar Design Accommodates Farming Equipment 

“Researchers in China have built a 10 kW spectral-splitting concentrator agrivoltaic system that accommodates small farming equipment below it. The installation relies on 128 concentrator modules integrating each an ultra-white and toughened concentrating curved glass (CCG), a multilayer polymer film (MPF) and 23%-efficient interdigitated-back contact (IBC) crystalline silicon solar cells provided by Sunpower.” – PV Magazine 

Justice Driven Agrivoltaics: Facilitaing Agrivoltaics Embedded in Energy Justice

Agrivoltaics comprises solar energy generation and agricultural activities co-located to create multi-purpose agricultural solar energy systems. In 2021, the global agrivoltaics sector was valued at USD $3.6 billion and is projected to grow to USD $9.3 billion by 2031. Agrivoltaics projects have successfully attracted increasing investment and research demonstrating the technical, economic, and scientific rationale to advance agrivoltaics as a crucial technology to achieve net zero emissions goals. The legal framework enabling agrivoltaics development is at varying stages of maturity across different jurisdictions. This study provides the first socio-legal study of agrivoltaics development applying an energy justice framework.

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Case Study: University of Delaware Agrisolar Research 

As we strive for climate change solutions, competition over land for food production or clean energy production is an emerging challenge to address this challenge, demonstrations of systems that produce energy and food on the same land are needed to usher in solution-scale adoption of these practices. A new research project at the University of Delaware (UD) will study the results of growing food crops underneath uniquely designed PV solar arrays. SolAgra Corporation will oversee the installation of two solar arrays at the UD Newark and Georgetown campuses. Once built, these sites will have the potential to demonstrate just how symbiotic solar energy and agricultural production can be. 

Professors Steven Hegedus, UD Department of Electrical and Computer Engineering, Gordon Johnson of the Plant and Soil Sciences Department, and Emmalea Ernest, Agriculture Program Leader, will work with their students to investigate the potential benefits to food crops grown beneath the PV arrays. All the preliminary engineering studies for the project are completed and approved, and construction is on track to be completed by the start of the growing season in April 2024. UD will fund the installation of the solar arrays and the initial crop plantings underneath. Further funding from the US Department of Agriculture and the US Department of Energy is being pursued to sustain a multiyear study of the sites. 

Barry Sgarrella, founder and CEO of SolAgra, said he developed the raised solar platform that will be used in the UD project to “help farm families be more profitable and to slow the trend of farmland being consumed by commercial development.” The SolAgra Farming Array™ will consist of elevated array segments with 15.5 feet of clearance to accommodate the tallest agricultural equipment. The racking will be assembled and the solar panels installed at ground level and then hinged into an upright position. 

 The panels will track the sun to increase energy production by as much as 15% and, when needed, they can be rotated so the panel edge is perpendicular to the sun to allow the maximum amount of sunlight to hit the crops below, a function Sgarrella calls CounterTracking™. This, coupled with the unique ability to shift the entire array east or west, called DynamicShifting™, will deliver varying degrees of sunlight or shade to crops planted below as needed. The rows of solar modules will be installed on 11.25-foot centers, a relatively dense panel row spacing for agrisolar cropping applications.  

Dynamic Shifting allows the entire array to move side to side for the least amount of shading possible.

Each array segment will be 35 by 45 feet and is designed to hold enough solar panels to produce 17 kW of electricity. The array segments will be modular and can be scaled up to much larger size arrays. Each research site at the UD project will contain two array segments totaling 68 kW of installed solar panels. The two systems will be identical except that the array installed on the Newark campus will house bifacial solar panels to study how much electric production can be gained from light reflecting off the crops and ground back to the underside of the panels. Sgarrella stated that the cost to install a segment is comparable to other raised-platform solar arrays of the same size, and costs would decrease for larger installations as economy of scale is achieved.  

According to Professor Hegedus, part of the research will involve looking at crop production at different shading levels. Photo saturation is the point at which plants cannot efficiently utilize more sunlight in the photosynthesis process and once the crops are at that point, it makes sense to utilize the light for energy production. The crops that will be included in this study are strawberries, tomatoes, peppers, and lettuce and were chosen because of their high market value. The flexibility of the SolAgra Farming Array™ design will allow the researchers, through controls on their smart phone or tablet, to provide full sun, full shade, or anything in between based on individual crop needs. The results can then be used to help develop shading schedule algorithms that can control the system for different crops. 

Sensors will be used to measure direct and diffuse illumination under the panels, soil and air temperatures, humidity, and crop temperatures to start quantifying crop benefits. It’s expected that the soil in the shade of the panels will retain moisture and that the crops will require less irrigation, which has been shown as a benefit of agrivoltaic cropping systems in other research.  

The researchers will also orient the panels horizontally to test the system’s ability to protect crops from severe weather like rain or hale. Even in this horizontal “umbrella” position, the panels will be able to produce 80% of their rated power. The benefits of protecting crops from damaging hail and heavy rain are evident, but many crops could benefit from the protection and shade control this system could offer. For example, this system could protect against sunscald, which can affect most crops in the right conditions and render them unmarketable. And, if grape growers could control sun levels, they could affect the acidity and sugar levels of the grape, which is very important in wine production. Many crops could benefit if growers could protect them with a solar panel covering, especially as weather conditions become more extreme. 

An umbrella effect is created when the solar panels are placed in a horizontal position and shifted over the top of each crop row.

Professor Hegedus believes that one of the biggest indirect benefits of proving this type of agrisolar system is that opposition to large solar installations on farmland might dissipate once neighbors realize that farming is not being replaced by solar panels but rather augmenting with an additional layer of income. He said, “farming is just carbon-based solar energy so now we’re combining two different ways of harvesting that energy.”  

The project’s researchers will be challenged by the quantity of data gathered from multiple sensors over a nine-month growing season at two locations. Advanced data analytic techniques will be necessary to organize and effectively interpret all the information. Future work will utilize the results from the study to form shading schedules that are tuned to each geographic and climate region to accommodate sun angle changes and local weather conditions so that the technology can be effectively utilized by farmers. 

In the face of climate change, well-designed agrisolar systems may give farmers a better chance to stay in business. Having the ability to protect crops and to control the shade levels could optimize production while at the same time producing revenue from solar power production, keeping farmland in production and profitable. Applications of this technology will be studied at UD in the coming years over the course of this project.  

Photos courtesy of Solagra.

Case Study: Hawai’i Agriculture Research Center

Crops growing under solar panels at the Hawai’i Agriculture Research Center. 

By Anna Richmond-Mueller, NCAT Energy Analyst  

In Mililani, Hawai’i, a one-acre agrivoltaic research and development site run by the Hawai’i Agriculture Research Center (HARC) is working to grow fruits and vegetables for their community, while also discovering which crops grow best locally in an agrivoltaic setting. This agrisolar project is just one of many ways HARC has been working to foster and improve agribusiness in Hawai’i for over 125 years. The overarching goal of the project is to determine how to develop novel agricultural production systems for replication at commercial scale, while simultaneously increasing the productivity and profitability of agrivoltaic sites in Hawai’i.  

Nestled within a larger 230-acre solar system consisting of bifacial auto-tracking panels, the site is a collaboration between HARC, Longroad Energy, AES Corporation, and Clearway Energy Group, which owns the array. HARC researchers believe that agrivoltaic projects require research and development in the local environment to determine optimal infrastructure design, crop selection, and agronomic practices. With this in mind, agricultural construction and environmental monitoring began on-site in 2021. 

By June 2022, preparation for the first planting of crops underneath the panels began. Researchers treated the area for weeds, disked compost into the soil, and installed four lines of dripline irrigation in each raised bed. A total of eight 180-foot beds were constructed, containing 14 different crops for initial trialing: radish, daikon, melons, kabocha squash, broccoli, cauliflower, bush beans, eggplant, poha berries, bunching onion, lavender, strawberries, sweet potato, and dryland taro. While most of the plants were successfully cultivated, researchers considered the 2022 growing season to be a screening process that allowed them to choose which crops they will plant on a larger scale in the coming years.  

In addition to the in-ground plantings, hydroponic lettuce trials were also conducted in four commercial-scale troughs between the rows of solar panels. Five lettuce varieties were chosen based on what is most popular in commercial markets in Hawai’i . By December 2022, eight cycles had been harvested and yield data collected for detailed analysis as part of an ongoing graduate school thesis project at the University of Hawai’i .  

Agrivoltaic projects like this have the potential to help meet both energy and food production needs for the state, while simultaneously optimizing land resources. HARC has successfully demonstrated that agricultural activities can be conducted on solar sites with minimal impact to existing operations and will hopefully expand their research beyond a single acre plot in the coming years.  

Photo courtesy of Hawai’i Agriculture Research Center. 

Potential of Agrivoltaics Systems Into Olive Groves in the Mediterranean Region

This paper focuses on integrating agrivoltaics systems within super-intensive olive groves in the Mediterranean region. A dual model is used to calculate the suitable transparency of PV modules, representing the area not occupied by PV cells.

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