Tag Archive for: Agrivoltaics

New Reports Highlight Best Practices of Combining Solar Energy and Agriculture

Two new reports funded by the U.S. Department of Energy Solar Energy Technologies Office highlight the potential for successfully and synergistically combining agriculture and solar photovoltaics technologies on the same land, a practice known as agrivoltaics. One report details the five central elements that lead to agrivoltaic success, while the other addresses emerging questions for researchers related to scaling up agrivoltaic deployment, identifying barriers, and supporting improved decision-making about agrivoltaic investments. Learn more about the reports’ findings.

The first report, The 5 Cs of Agrivoltaic Success Factors in the United States: Lessons From the InSPIRE Research Study, examines the Innovative Solar Practices Integrated with Rural Economies and Ecosystems (InSPIRE) project, which was funded by the U.S. Department of Energy (DOE) Solar Energy Technologies Office (SETO) starting in 2015. Over the past seven years, the project’s multiple phases have studied the co-location of solar with crops, grazing cattle or sheep, and/or pollinator-friendly native plants, and the resulting ecological and agricultural benefits.

According to InSPIRE research, there are five central elements that lead to agrivoltaic success:

  • Climate, Soil, and Environmental Conditions – The location must be appropriate for both solar generation and the desired crops or ground cover. Generally, land that is suitable for solar is suitable for agriculture, as long as the soil can sustain growth.
  • Configurations, Technologies, and Designs – The choice of solar technology, the site layout, and other infrastructure can affect everything from how much light reaches the solar panels to whether a tractor, if needed, can drive under the panels.
  • Crop Selection and Cultivation Methods, Seed and Vegetation Designs, and Management Approaches – Agrivoltaic projects should select crops or ground covers that will thrive in the local climate and under solar panels, and that are profitable in local markets.
  • Compatibility and Flexibility – Agrivoltaics should be designed to accommodate the competing needs of solar owners, solar operators, and farmers or landowners to allow for efficient agricultural activities.
  • Collaboration and Partnerships – For any project to succeed, communication and understanding between groups is crucial.

The 5 Cs of Agrivoltaic Success Factors in the United States: Lessons From the InSPIRE Research Study

This report examines the NREL Innovative Solar Practices Integrated with Rural Economies and Ecosystems (InSPIRE) project, which was funded by the U.S. Department of Energy (DOE) Solar Energy Technologies Office (SETO) starting in 2015. Over the past seven years, the project’s multiple phases have studied the colocation of solar with crops, grazing cattle or sheep, and/or pollinator-friendly native plants, and the resulting ecological and agricultural benefits.

According to InSPIRE research, there are five central elements that lead to agrivoltaic success:

  • Climate, Soil, and Environmental Conditions – The location must be appropriate for both solar generation and the desired crops or ground cover. Generally, land that is suitable for solar is suitable for agriculture, as long as the soil can sustain growth.
  • Configurations, Technologies, and Designs – The choice of solar technology, the site layout, and other infrastructure can affect everything from how much light reaches the solar panels to whether a tractor, if needed, can drive under the panels.
  • Crop Selection and Cultivation Methods, Seed and Vegetation Designs, and Management Approaches – Agrivoltaic projects should select crops or ground covers that will thrive in the local climate and under solar panels, and that are profitable in local markets.
  • Compatibility and Flexibility – Agrivoltaics should be designed to accommodate the competing needs of solar owners, solar operators, and farmers or landowners to allow for efficient agricultural activities.
  • Collaboration and Partnerships – For any project to succeed, communication and understanding between groups is crucial.

Successes and failures of prior agrivoltaic projects will inform new innovations as agrivoltaic projects continue to be deployed globally. This report represents a synthesis of lessons learned from agrivoltaic research field sites located across the United States as part of the InSPIRE project. The projects considered represent a diverse mix of geographies, agrivoltaic activities, and technology configurations. In this report, we have provided a list of features that contribute to the success of agrivoltaic installations and research projects, with partnerships playing a crucial role in both. The researchers suggest future research activities that align with these core principles as well as other approaches to grow agrivoltaic research efforts globally.

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Case Study: Jack’s Solar Garden

An aerial view of Jack’s Solar Garden

Jack’s Solar Garden is a  community solar garden in Boulder County, Colorado. With its 1.2-MW, single-axis tracking solar system, it is the largest commercial agrivoltaics research site in the United States. Covering over four acres of land on a 24-acre farm, Jack’s Solar Garden enables researchers from the National Renewable Energy Laboratory (NREL), Colorado State University (CSU), and the University of Arizona (UA) to study the microclimates created by its solar panels and how they impact vegetation growth. Additional partners include the Audubon Rockies, which planted over 3,000 perennials around the perimeter of the solar array, Sprout City Farms (SCF), the main cultivator of crops beneath the solar panels, and the Colorado Agrivoltaic Learning Center (CALC), which provides on-site educational opportunities for community groups to learn more about agrivoltaics. Jack’s Solar Garden also offers an annual stipend to an Artist on the Farm to engage the community on-site through their preferred art form. 

Electricity generated by Jack’s Solar Garden — enough to power about 300 average homes in Colorado annually — is sold to various subscribers via Xcel Energy’s Solar*Rewards Community program, where subscribers recieve a percentage of the net metered production as credits against their monthly electricity bills. Over 50 residents, five commercial entities (Terrapin Care Station, In The Flow: Boutique Cannabis, Western Disposal, Premiera Members Credit Union, and Meati), and two local governments (Boulder County and the City of Boulder) subscribe to Jack’s Solar Garden to support local, clean energy production, along with all the social and environmental benefits this development provides. Jack’s Solar Garden also donates 2% of its power production to low-income households through the Boulder County Housing Authority.  

Byron Kominek tilling under the panels at Jack’s Solar Garden

The solar array is designed to optimize electricity production while enabling researchers and agricultural workers to operate within the system. Torque tubes were elevated to 6-6.5 feet and 8 feet for two-thirds and one-third of the property, respectively, allowing researchers to study the difference these heights have on the microclimates and growing conditions of various crops within the solar array. During construction, land disturbance was minimized, leaving the long-standing brome and alfalfa forage relatively unharmed. Further, metal mesh was attached beneath the solar panels to help protect people within the solar array from electrical wires. 

Lettuce, Clary Sage, Grassland, and Raspberries all grown under the panels at Jack’s Solar Garden

Research at Jack’s Solar Garden includes: 

  • Crop Production and Irrigation Study to determine crop yields at different locations within the solar array with varying amounts of sunlight, shade, and allotted irrigation. 
  • Pollinator Habitat Research to measure the growth and performance of pollinator habitat seed mixes and evaluate different cost-effective vegetation-establishment techniques. 
  • Pasture Grass Research measuring the growth and performance of dryland pasture grass seed mixes with different cost-effective seeding methods. 
  • Grassland Ecology & Physiology Research seeking to understand the health and functions of grassland ecosystems within a solar array by studying light patterns, soil moisture retention, plant production and physiology, forage quality, and grassland resilience. 
  • Ecosystem Services Research evaluating multiple ecosystem services, such as carbon sequestration, erosion control, pollinator habitat, weed suppression, and microclimate moderation, provided by native vegetation and introduced pasture species within a solar array. 

These research projects were made possible through the dedication of the Kominek family, owners of Jack’s Solar Garden, to improve the economics of their hay farm while benefiting their local community. Local and State regulations supported the Kominek family’s ability to build Jack’s Solar Garden, including:  Colorado State legislation allowing for locally owned and interconnected community solar gardens as well as a Renewable Portfolio Standard that enables locally owned community solar gardens to generate 1.5x RECs per MWh; City of Boulder and Boulder County building codes requiring net zero for new homes  over 5,000 sq. Ft. and energy conservation codes that require either cannabis grow houses to pay taxes on energy consumed or to subscribe to local community solar gardens; and Boulder County’s Land Use Code update that provides solar array construction on prime farmland with a special land-use review process. 

Massachusetts Solar Pollinator Meadow Flourishes 

“Last year, the horticulture staff at the Arnold Arboretum of Harvard University planted a new pollinator meadow at the Arboretum’s Weld Hill Research and Administration Building. 

Wild-collected seeds of native perennials were sown beneath, between, and around an array of 1,152 solar panels, envisioned as an ecological and technological experiment. As these plants come into their own this season, the Weld Hill landscape champions two of the Arboretum’s key sustainability initiatives—increasing the capture and use of renewable energy and enhancing habitat for urban pollinators and other wildlife. 

As plant life has proliferated across the field, so has the traffic of visiting insects. For example, an early morning walk past the arrays showcases the dauntless industry of thousands of bumblebees gathering pollen and sipping nectar. Bumblebees tolerate cooler morning and evening temperatures than many other pollinators. They rise early, work late, and even sleep underneath flower petals at night. 

Now in its second growing season, the solar meadow at Weld Hill teems with more than 30 species of native, wild-collected flowers and grasses. This number will increase through additional plantings over the coming years. The variety of species sowed in the landscape ensures ready blooms for pollinators (and curious visitors) throughout spring, summer, and fall.” – Arnold Arboretum  

AgriSolar News Roundup: Cows in Agrisolar, Agrisolar in Nebraska, Small Farms Using Kunekune Pigs 

Michigan Agrisolar Farm Includes Cattle 

“Since farms use a significant amount of energy, generating electricity directly on the farm is appealing for those seeking to reduce expenses. Also, farming-friendly solar is possible where several farms have married on-farm solar with rotational grazing of livestock. While sheep have been the predominant livestock used in solar pastures, new approaches show the possibility of harvesting the sun and providing pasture for grass-fed cattle on the same site. 

Farming-friendly solar is made possible by engineering a system where the panels are raised upwards of eight feet off the ground, allowing cattle to move beneath. On hot summer days the cattle seek relief from the sun in the shade from the panels. Similarly structured to a carport, the elevated solar structure is designed to withstand rugged outdoor applications with a properly supported foundation to manage the higher wind pressure.” – Michigan Farm News 

Nebraska Pork Producers Benefit from Agrisolar  

“A Northeast Nebraska pork producer is using renewable energy to promote sustainable agriculture and offset energy consumption on his farm. 

Jason Kvols tells Brownfield he installed 300 solar panels on the top of his hog barns two years ago and an app tracks the impact on the environment. ‘It coverts it to pounds of carbon dioxide saved through this solar system.  Over the two years, it’s up to 432,000 pounds of CO2 that my system has saved in production from two years.’ 

He says he received a 26-percent tax credit on the project, and it has a 7- to-8-year payoff period.” – Brownfield 

Kunekune Pigs Found to be Ideal for Small Farms 

“Kunekune (pronounced “cooney cooney”) pigs are a good option for small farms and homesteads. The animals’ gentle nature, manageable size, and low input requirements beyond minimal rations and standard veterinary care like vaccinations and de-worming, make them a smart pick for those looking for an entry point into livestock production.” – Eco Farming Daily 

You can find a free Kunekune Pig Guide here, provided by Eco Farming Daily. 

Ecosystem Enriching and Efficient Solar Energy: Exploring the Effects of Pollinator-Friendly Solar Facilities on Ecosystem Function and Solar Panel Efficiency

As the solar energy industry grows, many hundreds of thousands of acres of land will be transformed into solar panel facilities. With this large change in land use, there is the opportunity to promote biodiversity and support pollinators by using pollinator-friendly management practices at the solar facilities. This paper explores the ecological and economic effects of a pollinator-friendly solar facility compared to a turfgrass solar facility. The researcher hypothesized that a pollinator-friendly solar facility would be functionally equivalent in pollinator support and overall insect diversity to a pollinator-friendly non-solar field and that both sites would have far greater pollinator support and insect diversity than a turfgrass solar field. To test this hypothesis, vegetation and insect sampling were conducted and the resulting data were analyzed for differences in vegetative and insect diversity and pollinator abundance at a pollinator-friendly solar facility, a turfgrass solar facility, and a reference non-solar pollinator-friendly field. The diversity analysis revealed that the pollinator-friendly solar site was overall functionally equivalent to the non-solar pollinator-friendly site and the turfgrass solar site had low insect and vegetative diversity, but high insect abundance. Photovoltaic solar panel energy production is negatively affected by high temperatures. Therefore, to maximize energy production and promote biodiversity native forbs may be incorporated into a solar facility landscape to cool the solar panels by the cooling effect of transpiration and produce more energy than a traditional turfgrass landscaped solar facility throughout the growing season. Overall, this study supports the idea that pollinator-friendly landscapes could be more economically viable, as pertaining to energy output, and more ecologically beneficial compared to turfgrass. More research is necessary to further investigate and test the patterns seen at only these two solar sites, but these results are encouraging for the future widespread implementation of pollinator-friendly management practices in solar facilities across the Mid-Atlantic.

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Effects of Shading Nets on Reactive Oxygen Species Accumulation, Photosynthetic Changes, and Associated Physiochemical Attributes in Promoting Cold-Induced Damage in Camellia sinensis (L.) Kuntze

Climate change and extreme weather affect tea growing. A competitive tea market needs quick, short-term solutions. This study evaluates the effects of various shade nets under mild and extreme cold stress on tea leaf physiology, photosynthetic alterations, antioxidant activities, and physiochemical characteristics. Tea plants were treated with SD0 (0% non-shading), SD1 (30% shading), SD2 (60% shading), and SD3 (75% shading). The 30%, 60%, and 75% shade nets shielded tea leaves from cold damage and reduced leaf injury during mild and extreme cold conditions compared with SD0% non-shading. Shading regulates photochemical capacity and efficiency and optimizes chlorophyll a and b, chlorophyll, and carotenoid contents. Moreover, carbon and nitrogen increased during mild cold and decreased in extreme cold conditions. Shading promoted antioxidant activity and physiochemical attributes. In fact, under 60% of shade, superoxide dismutase, peroxidase, catalase, and omega-3 alpha-linolenic acid were improved compared with SD0% non-shading during both mild and extreme cold conditions. From these findings, we hypothesized that the effect of different shades played an important role in the protection of tea leaves and alleviated the defense mechanism for “Zhong Cha 102” during exposure to a cold environment.

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Geospatial Assessment of Elevated Agrivoltaics on Arable Land in Europe to Highlight the Implications on Design, Land Use and Economic Level

Agrivoltaic systems have an increasing interest. Realizing this upcoming technology raises still many challenges at design, policy and economic level. This study addresses a geospatial methodology to quantify the important design and policy questions across Europe. An elevated agrivoltaic system on arable land is evaluated: three crop light requirements (shade-loving, shade-tolerant and shade-intolerant) are simulated at a spatial resolution of 25 km across the European Union (EU). As a result, this study gives insight into the needed optimal ground coverage ratio (GCR) of the agrivoltaic system for a specific place. Additionally, estimations of the energy production, levelized cost of energy (LCOE) and land equivalent ratio (LER) are performed in comparison with a separated system. The results of the study show that the location-dependent solar insolation and crop shade tolerance have a major influence on the financial competitiveness and usefulness of these systems, where a proper European policy system and implementation strategy is required. Finally, a technical study shows an increase in PV power of 1290 GWp (almost × 10 of the current EU’s PV capacity) if potato cultivation alone (1% of the total arable agricultural area) is converted into agrivoltaic systems.

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Pollinator-Friendly Solar Scorecards

The push toward carbon-free and renewable energy sources has precipitated a nationwide (United States) trend to increase solar generation via ground-mounted photovoltaic (PV) arrays. Beyond carbon benefits, one possible way to provide additional ecological value of solar PV projects is to co-locate pollinator habitat when site conditions permit. Around 2015, the concept of a “scorecard” emerged that could assess the value of a solar project to pollinator species. The development and application of these scorecards, to date, has not been controlled by any central organization. Scorecards are being developed on a state-by-state basis using various processes, by a variety of subject matter experts, and using a range of oversight and review approaches. As such, there is variation between different state scorecard programs and divergent opinions regarding the scorecards themselves. Given that developing state and local laws and incentive programs are linked to the pollinator-friendly solar scorecards, it is important to consider the basis of the scorecards themselves. With interest in co-location of solar with pollinator habitat, this comprehensive study of existing pollinator solar scorecards considers the level of consistency across the scorecards, analyzes the specific scorable elements and their relative weighting, and investigates the factors that influenced scorecard development. A total of 15 state scorecards and one nonspecific scorecard available as of April 2021 were reviewed to identify common and differentiating features. A categorization system for individual scoring elements was created to facilitate numeric assessment across the available scorecards. Further, in order to understand the unique motivations and processes that influenced the design of the scorecards, interviews were conducted with 34 experts involved in scorecard design, policy development, and use, including university professors, state agency staff, and solar project developers, owners, and operators. Research uncovered a general lack of rigor, consistency, and oversight for scorecard design methodology, version control, and use. However, if the scorecards can be predictive of ecological outcomes – healthy pollinator habitat – then they may still be meeting their primary purpose. Field-based research is necessary to determine if there is a correlation between the points received on a pollinator-friendly scorecard and the actual solar PV site habitat conditions.

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AgriSolar News Roundup: Crops and Livestock in AgriSolar, AgriSolar Adds Value to Low-Yield Crops, Food Security in Brazil Using AgriSolar 

AgriSolar Shown to be Ideal for Various Crops and Livestock 

“Agrivoltaics, the practice of producing food in the shade of solar panels, is an innovative strategy that combines the generation of photovoltaic electricity with agricultural land use. The outcome is an optimized relationship between food production, water, and energy – the so-called Food-Energy-Water Nexus. 

According to research by Prof. Greg Barron-Gafford (University of Arizona), potential crops include hog peanut, alfalfa, yam, taro, cassava, sweet potato, and lettuce. In a 2019 study, he analyzed cherry tomatoes, chiltepin peppers, and jalapeno production in combination with solar production. Cherry tomato production doubled under solar panels, while chiltepin pepper production tripled. 

Sheep seem to be the best livestock for agrivoltaics. They do an excellent job of keeping vegetation down, which lowers maintenance and long-term operational costs. According to research by Cornell University, sheep grazing resulted in “2.5 times fewer labor hours than mechanical and pesticide management on-site.” – HDI 

AgriSolar Adds Value to Low-Yield Crops 

“A group of 35 French agricultural entrepreneurs decided to change their agricultural practices to adapt to the low quality of their groundwater and chose agrivoltaics as a way to compensate for crop yield losses. 

In May, we experienced an episode of high heat and drought. Under the panels, which retained the evapotranspiration of the plants, we found that the plants were greener and better developed than between the rows. So, we think the return will be higher than what we originally estimated,” Jean-Michel Lamothe, a farmer in France’s Lands department and vice president of the French Federation of agrivoltaic producers (FFPA), told PV Magazine. 

“We decided to grow plants rich in omega-3s, which respond well to our water quality problem and the climate of the region: flax, chia, camelina, rapeseed, and sunflower,’ he further explained. ‘And we will compensate for the drop in productivity with revenues from photovoltaics.’” – PV Magazine 

AgriSolar Benefits Crops in Water-Stressed Regions of Brazil 

“Brazil’s first agrivoltaic system is called Ecolume. It was developed by a network of more than 40 Brazilian researchers and funded by CNPq, the National Council for Scientific and Technological Development. 

The Ecolume Agrivoltaic System (SAVE) makes the most of the scant local water resources by reusing water and collecting rainwater. It consists of 10 photovoltaic panels that cover 24 square meters (258 square feet), installed at a height of 2 meters (6 feet) above the ground. 

In simulations carried out by Ecolume researchers, the agrivoltaic system produced up to 70% more vegetables and lowered the need for water, depending on the crop and environment. A study carried out at the University of Arizona, in the southwestern U.S. — a region that also experiences water scarcity — showed yields two to three times higher for some fruits and vegetables planted under solar panels. The SAVE water recycling and treatment systems also showed a 90% savings in water used for irrigation.” – Mongabay