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: solar-suitable crops
The AgriSolar Clearinghouse Podcast officially kicks off with a conversation between Meg Caley, Executive Director and co-founder of the Colorado nonprofit Sprout City Farms and NCAT Energy Director Stacie Peterson. They discuss the many additive benefits of agrisolar, the challenges of farming in an obstacle course, and the importance of community. AgriSolar podcast episodes will be available on Voices from the Field, NCAT’s ATTRA sustainable agriculture podcast series.
Sprout City Farms began in 2010 with a vision of increasing food access and community resiliency through farming underutilized urban land. Among its partnerships, Sprout City Farms works with Jack’s Solar Garden in Longmont, Colorado, growing crops in the spaces between solar panels at the site, which is the largest agrivoltaic research facility of its kind in the United States.
You can read more about Sprout City Farms, Jack’s Solar Garden, and the Colorado Agrivoltaic Learning Center at these websites:
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
This article offers practical advice for agrivoltaic systems on how to implement an agricultural area under ground-mounted photovoltaic-power systems without agricultural “pre-plans.” These systems are useful for policy making and optimizing land use efficiency in terms of energy production, food supply, environmental impact, local economy, and sustainable societies.
By: Mariah Rogers, Graduate Student, University of Arizona
Do plants taste different under solar panels? Do they taste better? At the Biosphere 2 Agrivoltaics Learning Lab, we studied just that.
Why Should We Use Agrivoltaics?
Agrivoltaics—the production of agriculture and solar photovoltaic energy on the same parcel of land—is gaining attention as farmers are facing new struggles amid the climate crisis. With agrivoltaics, farmers can reduce water consumption, produce renewable energy, and continue to cultivate their land. However, there is skepticism toward growing crops under solar panels, as farmers may have to change the types of plants that are more shade tolerant.
The Biosphere 2 Agrivoltaics Learning Lab
At the Biosphere 2 Agrivoltaics Learning Lab (B2AVSLL), we study the microclimate—that localized environment under the solar panels— and how plant adaptations occur in the shade of the agrivoltaic system. Some of the adaptations that plants make in the agrivoltaic microclimates include differences in yield, changes to plant morphology (leaf size, fruit shape and color), and alterations in metabolites. These adaptations may cause differences in how people perceive these crops. To study these differences, we grow a slew of different crops underneath solar panels.
We grow tomatoes, basil, potatoes, beans, squash, and lavender, just to name a few. While some of the plants grown at B2AVSLL are heat tolerant, crops grown in this region of the U.S. still require a lot of water. With agrivoltaics, we can reduce water consumption and still have a good yield. So, it is in our best interest to figure out if they would be successful both for the environment and in the market.
The Study Goals
To understand how these crops would do in the market, we conducted a consumer sensory study at the University of Arizona. The three goals of the study were to: (1) to understand if people perceived a difference between agrivoltaic-grown crops vs. crops grown in full sunlight (control); (2) determine if people preferred agrivoltaic-grown crops compared to control; and (3) discover if people were willing to pay more for crops grown in agrivoltaic conditions.
A total of 105 people participated in the study. Panelists were subjected to different conditions and samples, based on the site and the day they were tasting samples. Tomato and basil, potato and bean, and potato and squash were tasted by panelists.
Does Agrivoltaics Change the Flavor of Plants?
To understand if there was a difference between agrivoltaic- and control-grown samples, we used a triangle test where participants were given three samples with a random three-digit code; two of the samples were the same and one was different. We then asked the participants to pick which sample was the “odd one out.”
So, did agrivoltaics change the flavor of the crops? Yes and no. Tomato, bean, and squash samples (all fruits) were perceived as different by tasters. Basil and potato samples were not perceived as significantly different by tasters.
Does Agrivoltaics Make Plants Taste Better?
To understand if there was a preference between samples from the two growth conditions, we then conducted a paired preference test. We gave tasters two samples with random three-digit codes and asked if they preferred one sample more than another, or if they preferred neither sample.
Unsurprisingly, the results were mixed. People significantly preferred beans grown in the control setting over those grown in agrivoltaics. In addition, agrivoltaic-grown basil, potato, and squash samples were preferred by tasters.
Are People Willing to Pay More for Agrivoltaic-grown Produce?
After the triangle and preference tests, we asked participants if they would be willing to pay more or less for their favorite samples. Overall, we found that participants were willing to pay the same or more for all samples after they knew that their favorite samples were grown in agrivoltaic systems.
What Does This Mean for Farmers and Investors?
Because consumers can’t tell a significant difference in vegetable samples, and they preferred basil, potato, and squash, it may be in farmers’ best interest to grow these crops, especially in the desert. By marketing the produce as grown under solar arrays, and educating consumers about agrivoltaics, farmers may be able to sell their produce for slightly more at farmers markets.
What Does This Mean for You as a Consumers?
Buying for foods that are grown using agrivoltaics means supporting solar energy generation through purchasing fruits or vegetables. If you already go to the farmers market to buy fruits and vegetables, you may want to consider buying agrivoltaic-grown produce. If you want something that tastes like what you already buy from the farmers market, then you may want to buy vegetables. If you are looking for a different tasting product, you may want to buy fruits grown under agrivoltaics. You can be the judge whether you prefer one growth condition over another.
By Lee Walston and Heidi Hartmann, Argonne National Laboratory
Many of us have witnessed regional land-use transformations towards renewable energy in the last decade. As the fastest growing electricity generating sector in the U.S., solar energy development has grown more than 20x in the past decade and is projected to be the dominant renewable source of electricity by 2040. The recent DOE Solar Futures Study predicts that over 1 terawatt (TW) of utility-scale solar electricity developments will be required to meet net-zero clean-energy objectives in the U.S. by 2050 (Figure 1). This represents a solar land-use footprint of over 10 million acres across the U.S. – roughly the combined area of Connecticut, Massachusetts, and Rhode Island.
A fundamental question we all face is how to balance solar energy development with other land uses such as agriculture. Given the current and projected land-use requirements, sustained development of solar energy will depend on finding renewable energy solutions that optimize the combined outputs of energy production, ecosystem services, and other land uses. Dual land-use approaches that co-locate solar energy with other forms of land uses, such as agriculture or habitat restoration, have emerged as promising strategies to improving the landscape compatibility of solar energy. The establishment of native pollinator-friendly vegetation at solar facilities (“solar-pollinator habitat”) is one strategy to improve the multifunctionality of these lands that not only provide renewable energy but also offer several ecosystem service benefits such as: (1) biodiversity conservation; (2) stormwater and erosion control; (3) carbon sequestration; and (4) benefits to nearby agricultural fields.
Understanding the true ecosystem service benefits of solar-pollinator habitat will require field studies in different geographic regions to examine the methods of solar-pollinator habitat establishment and link these processes with measured ecosystem service outputs. Given the time required to conduct these direct field studies, most discussions of solar-pollinator habitat thus far have centered on qualitative ecosystem outcomes. Fortunately, there are ways to quantitatively understand some of these potential outcomes. Native habitat restoration has been a focus of scientific research for many years, and we can use these studies to understand the regional methods for solar pollinator habitat establishment (e.g., types of seed mixes, vegetation management) and relate these habitat restoration activities with quantifiable ecosystem responses. For example, there are decades of research on the restoration of the prairie grassland systems in the Midwest and Great Plains – regions that have seen losses of over 90% of their native grasslands due to agricultural expansion.
Because many solar facilities in the Midwest are sited on former agricultural fields, research on ecological restoration of former agricultural fields could be very useful in understanding the establishment and performance of solar-pollinator habitat in the same region. We can look to these studies as surrogate study systems for solar-pollinator habitat and utilize the data from these studies to make inferences on the ecosystem outcomes of solar-pollinator habitat. Along with a team of research partners, we recently took this approach to quantify the potential ecosystem services of solar-pollinator habitat in the Midwest. Our goal was to understand how solar energy developments co-located with pollinator-friendly native vegetation may improve ecosystem services compared to other traditional land uses. We began by reviewing the literature to collect a range of data on vegetation associated with three different land uses: agriculture, solar-turfgrass, and solar-pollinator habitat. The data for each land use included information on vegetation types, root depths, carbon storage potential, and evapotranspiration, to name a few.
We then developed ecosystem service models for each land use scenario. The land uses corresponded to the following scenarios (Figure 2):
1. Agriculture scenario (baseline “pre-solar” land use);
2. Solar-turfgrass (“business as usual” solar-turfgrass land use) and
3. Solar-pollinator habitat (grassland restoration at solar sites).
We mapped and delineated 30 solar sites in the Midwest and used the InVEST modeling tool to model the following four ecosystem services across all sites and land-use scenarios:
- Pollinator Supply (Pollinator Model)
- Carbon Storage Potential (Carbon Storage Model)
- Sediment Export (Sediment Delivery Ratio Model)
- Water Retention (Annual Water Yield Model)
Our results, published in the journal Ecosystem Services, found that, compared to traditional agricultural land uses, solar facilities with sitewide co‑located, pollinator‑friendly vegetation produced a three-fold increase in pollinator habitat quality and a 65% increase in carbon storage potential. The models also showed that solar-pollinator habitat increased the site’s potential to control sedimentation and runoff by more than 95% and 19%, respectively (Figure 3). This study suggests that in regions where native grasslands have been lost to farming and other activities native grassland restoration at solar energy facilities could represent a win‑win for energy and the environment.
What do these results mean? We hope these results can help industry, communities, regulators, and policymakers better understand the potential ecosystem benefits of solar-pollinator habitat. These findings may be used to build cooperative relationships between the solar industry and surrounding communities to better integrate solar energy into agricultural landscapes. While our study provides a quantitative basis for understanding these potential ecosystem benefits, additional work is needed to validate model results and collect the primary data that would support economic evaluations to inform solar-native grassland business decisions for the solar industry and quantify the economic benefits of services provided to nearby farmers, landowners, and other stakeholders.
Increasing energy demands and the drive towards low carbon (C) energy sources has prompted a rapid increase in ground-mounted solar parks across the world. This represents a significant global land use change with implications for the hosting ecosystems that are poorly understood. In order to investigate the effects of a typical solar park on the microclimate and ecosystem processes, we measured soil and air microclimate, vegetation and greenhouse gas emissions for twelve months under photovoltaic (PV) arrays, in gaps between PV arrays and in control areas at a UK solar park sited on species-rich grassland. Our results show that the PV arrays caused seasonal and diurnal variation in air and soil microclimate. Specifically, during the summer we observed cooling, of up to 5.2 °C, and drying under the PV arrays compared with gap and control areas. In contrast, during the winter gap areas were up to 1.7 °C cooler compared with under the PV arrays and control areas. Further, the diurnal variation in both temperature and humidity during the summer was reduced under the PV arrays. We found microclimate and vegetation management explained differences in the above ground plant biomass and species diversity, with both lower under the PV arrays. Photosynthesis and net ecosystem exchange in spring and winter were also lower under the PV arrays, explained by microclimate, soil and vegetation metrics. These data are a starting point to develop understanding of the effects of solar parks in other climates, and provide evidence to support the optimisation of solar park design and management to maximise the delivery of ecosystem services from this growing land use.
Global energy demand is increasing as greenhouse gas driven climate change progresses, making renewable energy sources critical to future sustainable power provision. Land-based wind and solar electricity generation technologies are rapidly expanding, yet our understanding of their operational effects on biological carbon cycling in hosting ecosystems is limited. Wind turbines and photovoltaic panels can significantly change local ground-level climate by a magnitude that could affect the fundamental plant–soil processes that govern carbon dynamics. We believe that understanding the possible effects of changes in ground-level microclimates on these phenomena is crucial to reducing uncertainty of the true renewable energy carbon cost and to maximize beneficial effects. In this Opinions article, we examine the potential for the microclimatic effects of these land-based renewable energy sources to alter plant–soil carbon cycling, hypothesize likely effects and identify critical knowledge gaps for future carbon research. Land use change for land-based renewables (LBR) is global, widespread and predicted to increase. Understanding of microclimatic effects is growing, but currently incomplete, and subsequent effects on plant–soil C cycling, greenhouse gas (GHG) emissions and soil C stocks are unknown. We urge the scientific community to embrace this research area and work across disciplines, including plant–soil ecology, terrestrial biogeochemistry and atmospheric science, to ensure we are on the path to truly sustainable energy provision.
This report discusses the goal of agrisolar systems, which would generate electricity from raised solar panels and allow crop cultivation under the solar panels, and their development. Details of the report include the effect of raised solar panels and their effect on shading, which affects factors of the crops development. This information can be used to potentially optimize the design of agrisolar operations to most effectively benefit the crops included in the agrisolar operation.
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