Agrivoltaics have emerged as a game changer in the agriculture and renewable energy sectors. Combining the power of solar energy with traditional agricultural practices offers a promising path toward a greener future. Regarding embracing agrivoltaics, India and China stand at the forefront of this promising revolution with their vast agrarian landscape and untapped solar potential.
Agrivoltaics, derived from the words ‘agriculture’ and ‘photovoltaics’ – involves the dual use of agricultural land for cultivating crops and generating solar energy. Solar panels are mounted on stilts over agricultural land, in varying configurations to maximize land productivity. This combination forms a symbiotic relationship between the crops and solar panels that benefits the farmers and is a step towards sustainable development.
Agrivoltaics is an innovative approach combining agricultural production with solar energy generation, addressing critical land use, food security, and renewable energy challenges. This dual-use strategy has significant implications for achieving several United Nations Sustainable Development Goals (SDGs), particularly SDG 2, 7, SDG9, SDG11, SDG13, and 15.
1. Understanding Agrivoltaics
Agrivoltaic systems involve the co-location of solar photovoltaic (PV) panels and agricultural activities. This integration allows for the simultaneous production of food and energy, optimizing land use and enhancing overall productivity. The key types of agrivoltaic systems include:
a) AV-Cropping: Combining solar energy production with crop cultivation.
b) AV-Animal: Integrating livestock grazing with solar installations.
c) AV-Habitat: Enhancing ecosystems and biodiversity alongside energy production.
I. Benefits of AV systems
The literature highlights numerous benefits of AV systems implementation. This section summarizes the following eight benefits (see figure below):
(1) Renewable energy production and efficiencies.
(2) Greenhouse gas emissions reduction.
(3) Food production, land-use efficiency, and land restoration.
(4) Water-use efficiency and pollution prevention.
(5) Biodiversity conservation and habitat restoration.
(6) Climate change adaptation and increased resilience.
(7) Economic benefits.
(8) Sustainable development benefits
These systems can lead to improved efficiencies in land use, water conservation, and energy generation, while also providing economic benefits to rural communities through job creation and additional income streams for farmers.
2. Green Agriculture and Clean Energy
Current agricultural practices depend heavily on fossil fuels and chemical inputs that actively harm the foundation of the ecosystems that make agriculture possible. Hence, as we look for clean energy alternatives and meet nutritional demand for a growing population, it is imperative to find holistic solutions that are truly sustainable, economically and ecologically. AV systems provide renewable energy, avoiding fossil fuels and associated carbon emissions. A study mapping the potential for solar power production across different land cover types noted that deploying AV systems on just 1% of the ~1.6 billion hectares (ha) of global arable lands could offset all the world’s energy demand, with consequent greenhouse gas emission reduction (although energy storage solutions will be required to ensure constant energy availability from PV systems. Also, decoupling the deployment of solar PVs and land clearance helps conserve carbon stocks. Furthermore, plants grown in AV systems have been shown to accumulate higher biomass than conventional agricultural systems, including in arid conditions, with consequent increased soil carbon and sequestration benefits.
3. Economic Benefits
Agrivoltaics add an income stream to farmers through power generation and increase crop yields, which further stabilizes farmers’ financial stability. It reduces rural dependency on grid electricity which is often unreliable and lacks connectivity in rural areas, allowing rural people to use power generated on-site to meet their needs reliably and at low or no cost.
Using the same land for agricultural activities and energy generation creates diversified livelihood opportunities and revenue streams for farmers and reduces revenue volatility. In addition to the potentially higher yields under AV systems, energy access enables farmers to adequately store and process their produce. This results in better market timing and increased value and income, which are particularly relevant in many Global South countries where storage and processing are major challenges in agricultural value chains. Also, AV systems reduce farm operation costs by increasing water use efficiencies and the availability of self-generated electricity. Furthermore, AV farmers can become energy entrepreneurs and generate income by selling excess power to national or local mini-grids in countries with supporting policies. A study investigating the economic benefits of an AV system in the United States found a 30% increase in economic value compared to conventional agriculture.
Another study in China found that AV systems produced a 9%–20% annual return on investments, depending on crop type.
4. Social Benefits of Agrivoltaics:
Agrivoltaics not only enhances agricultural productivity and renewable energy generation but also brings significant social benefits to rural communities. Here are the key social benefits associated with agrivoltaics:
a) Empowerment of Local Communities:
Agrivoltaic projects often involve community participation in their design and implementation, fostering a sense of ownership among local residents. This engagement can empower communities to take charge of their energy and food systems, enhancing local governance and decision-making processes 1.
b) Job Creation and Economic Opportunities:
The installation and maintenance of agrivoltaic systems create new employment opportunities in rural areas. Jobs are generated not only in the solar energy sector but also in agricultural production, leading to increased economic activity and stability within these communities. This diversification of income sources is crucial for enhancing the financial resilience of farmers.
c) Enhanced Access to Energy:
Agrivoltaic systems provide a reliable source of clean energy, which can power homes, schools, and healthcare facilities in rural areas. Improved access to electricity enhances the quality of life, facilitates educational opportunities, and supports local businesses. This decentralized energy production reduces reliance on unstable grid systems.
d) Educational and Training Opportunities:
Implementing agrivoltaic projects often includes training programs that equip local residents with skills in solar technology, maintenance, and sustainable agricultural practices. This knowledge transfer not only enhances employability but also promotes sustainable practices within the community.
e) Improved Food Security:
By increasing agricultural productivity through enhanced crop yields (due to favorable microclimates created by solar panels), agrivoltaics contributes to food security in rural areas. This is particularly important as communities face challenges related to climate change and food supply disruptions.
f) Strengthened Social Cohesion:
Shared ownership and collaborative participation in agrivoltaic projects can enhance social bonds within communities. The collective effort required for project implementation fosters a sense of community spirit and collaboration among residents.
g) Market Diversification:
Agrivoltaics allows farmers to diversify their crops, including the cultivation of shade-tolerant varieties that may not have been feasible before. This diversification can lead to increased resilience against market fluctuations and climate impacts.
h) Environmental Awareness and Sustainability:
The integration of renewable energy with agriculture raises awareness about sustainable practices among local populations. Communities become more engaged in environmental stewardship as they witness the benefits of combining agriculture with clean energy production.
The social benefits of agrivoltaics extend beyond mere economic gains; they encompass empowerment, education, community cohesion, and improved quality of life for rural populations. By integrating agricultural practices with renewable energy generation, agrivoltaics presents a holistic approach to addressing the multifaceted challenges faced by rural communities today.
5. Environmental Benefits
Agrivoltaics produce clean energy, reducing reliance on fossil fuels and lowering greenhouse gas emissions. Also, the shade provided by the panels reduces water evaporation, conserving water resources and promoting sustainable agricultural practices.
6. Agrivoltaics for Sustainable Development
Agrivoltaics can help achieve sustainable development by achieving sustainable development goals (SDGs) and making a significant impact on resource use and outputs in agriculture. The following SDGs are achieved through agrivoltaics:
a) SDG 1: No Poverty, stable, supplementary income sources for subsistence and large-scale farmers.
b) SDG 2: Zero Hunger, increase in agricultural productivity, and improvement of food security.
c) SDG 7: Affordable and Clean Energy, by promoting the production of clean and affordable energy through solar power. By diversifying the energy mix and reducing reliance on fossil fuels, agrivoltaics helps mitigate climate change while ensuring access to sustainable energy sources.
d) SDG 8: Decent Work and Economic Growth. This approach creates employment opportunities in rural areas, stimulating economic growth and offering decent work prospects for local communities.
e) SDG 9: Industry, Innovation, and Infrastructure by promoting the development of sustainable infrastructure. By integrating agricultural and energy systems, agrivoltaics optimizes land use and reduces the need for additional land for solar installations, fostering innovation and sustainable development in both sectors.
f) SDG 11: Sustainable Cities and Communities, agrivoltaics contribute by facilitating the creation of resilient and sustainable communities. Its decentralized nature enables energy production closer to consumption centers, reducing transmission losses and enhancing energy security for communities.
g) SDG 13: Climate Action by actively reducing greenhouse gas emissions. Through the utilization of solar energy and sustainable agricultural practices, agrivoltaics plays a crucial role in mitigating climate change and building resilience to its impacts.
Additionally, agrivoltaics affect the light saturation point of plants. Plants have a limit to how much sunlight they can handle. Beyond that limit, too much light can harm them and make them more thirsty. With agrivoltaics, the solar panels provide shade to the plants, protecting them from excessive sunlight. This helps keep them healthy and reduces their need for water. The shade from solar panels also helps conserve water. It prevents water from evaporating too quickly from the soil, which is important because water is a valuable resource for growing crops. The water used to clean the solar panels can be collected and used for irrigation, saving even more water.
Furthermore, panel efficiency is higher when plants are growing alongside PV cells. The plants create a cooler environment, which helps the solar panels operate more efficiently. This means they can generate more electricity from the same amount of sunlight. Interestingly, farmers who use agrivoltaics have noticed that certain crops, like leafy greens, can have higher yields. This is because the shade from the solar panels protects the plants from the harsh sun. The panels also act as a barrier against strong winds, reducing the chances of crop damage. The shade helps prevent the growth of unwanted weeds. Lastly, agrivoltaics also bring benefits to our energy system by promoting the decentralized production of clean energy. This means we don’t have to rely as much on big power grids and can generate electricity closer to where it is needed, reducing transmission losses and reliance on distribution companies.
Agrivoltaics represents a transformative approach to land use that not only addresses food security and renewable energy needs but also supports a range of sustainable development objectives. By maximizing land productivity and fostering synergies between agriculture and energy production, agrivoltaic systems offer a promising pathway toward a more sustainable future.
7. Agrivoltaics Impact Crop Yields and Diversity
Agrivoltaics significantly impact crop yields and diversity by optimizing land use and creating favorable microclimates for various crops. Here’s a detailed overview of how agrivoltaics influences these aspects:
a) Impact on Crop Yields
Increased Yields Through Shading: Agrivoltaic systems provide partial shade from solar panels, which can reduce heat stress on crops. This shading effect leads to less evaporation and healthier plants, resulting in enhanced productivity. Studies have shown that certain crops can experience yield increases ranging from 20% to 60% when grown under solar panels.
Ø Specific Crop Performance:
a) Positive Outcomes: Crops like potatoes, sweet peppers, broccoli, and cabbage have shown improved yields in agrivoltaic settings. For instance, a study in Germany noted that potato yields under solar panels were above the national average.
b) Mixed Results: Lettuce and tomatoes exhibit varied responses; while some studies report increased yields for tomatoes despite reduced light exposure, others indicate lower yields due to shading effects. Similarly, garlic and spinach have shown decreased yields when grown under solar panels.
c) Maize and Rice: Maize has benefited from moderate shading, with increased yields observed at specific light saturation levels. Conversely, rice has experienced significant yield drops under similar conditions.
d) Water Use Efficiency: Agrivoltaics enhances water retention in the soil by reducing evaporation rates. This leads to improved water-use efficiency for crops like jalapeños and cherry tomatoes, which can see substantial increases in productivity due to better moisture conditions.
Ø Impact on Crop Diversity
a) Adaptation of Crop Varieties: Agrivoltaics encourages the cultivation of shade-tolerant crops such as leafy greens (e.g., lettuce) and other understory plants that thrive in less direct sunlight. This shift can promote greater crop diversity in the same land area.
b) Potential for Novel Ecosystems: By integrating diverse plant species beneath solar panels, agrivoltaics can create novel ecosystems that enhance biodiversity while simultaneously producing food and energy. Research indicates that strategic planting can lead to increased fruit production for certain varieties, such as chiltepin peppers.
c) Challenges with Light-Dependent Crops: While some crops adapt well to shaded environments, others that require full sun may struggle under solar panels. This necessitates careful selection of crop varieties based on their light requirements and adaptability to partial shade conditions.
Agrivoltaics offers a promising solution for enhancing both crop yields and diversity by leveraging the benefits of dual land use. The integration of solar energy production with agriculture not only boosts productivity but also supports sustainable practices that can adapt to changing climate conditions. As research continues to explore the optimal combinations of crops and solar technology, agrivoltaics stands out as a viable strategy for improving food security while promoting renewable energy sources.
Certain crops thrive particularly well in agrivoltaic systems, benefiting from the unique conditions created by the presence of solar panels. Here are the key crops that show significant advantages:
8. Crops That Benefit Most from Agrivoltaics
A. Leafy Greens:
Examples: Lettuce, and spinach.
Benefits: These crops are well-suited for shaded environments and can grow effectively under solar panels. The reduced sunlight helps prevent bolting, extending the growing season and improving yield quality.
B. Berry Crops:
Examples: Strawberries, raspberries, blueberries.
Benefits: Low-growing and often requiring less direct sunlight, these berries can be easily harvested without disturbing solar installations. Studies indicate that strawberries grown in shaded conditions have shown improved yields in some cases.
C. Specialty Crops:
Examples: Herbs (like basil) and medicinal plants.
Benefits: These crops typically require less sunlight and can thrive in the partial shade provided by solar panels, making them economically viable options for agrivoltaic systems.
D. Vegetables:
Examples: Potatoes, sweet peppers, broccoli, and cabbage.
Benefits: Potatoes have shown particularly high yields when grown under solar panels, often exceeding national averages. Other vegetables like sweet peppers also perform well due to reduced heat stress and improved moisture retention.
E. Low-Growing Legumes:
Examples: Peas and beans.
Benefits: These crops can thrive in cooler temperatures and are adaptable to the shaded conditions beneath solar panels, allowing for early planting and extended growing seasons.
F. Fruits and Orchards:
Examples: Grapes and apple trees.
Benefits: While some fruit crops may require more light, certain varieties can benefit from the microclimate created by solar panels. However, care must be taken as excessive shading can reduce yield—grapes have shown mixed results depending on shading levels.
G. Maize (Corn):
Benefits from moderate shading (up to about 21% reduction in sunlight), leading to increased yields due to better moisture retention and reduced heat stress. However, excessive shading can negatively impact growth.
Agrivoltaics provides a unique opportunity to enhance crop yields while simultaneously generating renewable energy. The most successful crops in these systems tend to be those that are either shade-tolerant or benefit from the cooler microclimate created by the solar panels. As research continues to evolve, understanding the specific needs of various crops will further optimize agrivoltaic practices for sustainable agriculture and energy production
There are numerous opportunities for AV systems to synergize the ecosystem service outputs of solar energy production and other compatible land uses. AV systems also align with several UN SDGs that could contribute to the global transition to renewable energy and sustainable development. The environmental benefits of AV systems are primarily created by methods to optimize land productivity. Land productivity can be optimized to meet a number of objectives for energy and food production, biodiversity conservation, and climate change mitigation. These objectives may not be mutually exclusive. For example, climate change is an increasing threat to agriculture and food security. Paradoxically, conventional agricultural practices are energy-intensive and contribute to climate change by accounting for about one-third of global GHG emissions. AV systems can help mitigate the negative interactions between climate change and agriculture by simultaneously improving agricultural production in arid regions and offsetting declines in food production from areas that have been impacted by climate change, while also mitigating the impact of agricultural land use practices toward climate change through lower GHG emissions and improved energy and water use efficiency.
AV systems can directly and positively impact SDG 7 “Ensure access to affordable, reliable, sustainable, and modern energy for all” by expanding and reducing the costs of solar energy through reducing O&M costs over the life of the project, creating new revenue streams, keeping agricultural land in production, and enhancing ecosystem services on these solar sites. While the advantages of AV systems align positively with many of the other SDGs, we believe the strongest contributions could be made in SSDGs9, 11, 13, and 15. For SDG 9, AV systems can help ensure rural areas have consistent access to renewable energy, which will be important for future energy and food needs. Similarly, for SDG 11, AV systems can be sited close to communities and cities that need energy and nutritional food sources. For SDG 13, AV systems will produce energy to offset fossil fuel sources, but also provide a source of carbon and methane sequestration from vegetation establishment. For SDG 15, AV systems can enhance natural habitats to provide refuge for plant, animal, and insect populations. These few examples highlight the relevance and impact AV systems can have on UN SDG goals and the need for more research to make these systems an established construction method for the solar industry.
v SOME CASE STUDIES :
Case study 1: Using AV to enhance ecological, economic, and socioeconomic benefits on degraded land in Jiangshan, China.
The agrivoltaic park in Jiangshan, China, is a privately-owned commercial-scale, 200 MW PV on-grid power plant with a total area of 4.2 km2 installed on degraded farmlands by Astronergy/Chint Solar Co. Ltd. The project’s upfront cost was $312 million USD. The park, which represents a practical model of using AV systems to address land degradation, is located on land that has become barren due to soil erosion. Unlike conventional PV, which involves difficult-to-get approval due to land-use change laws, the fact that the land was used for crops (the original designated use for the land) and energy made approval easier. The systems address land degradation, agricultural profitability, and PV industry development in an integrated manner using a business model that fuses power generation, agriculture,e, and ecotourism. It employs a multilayer PV installation (e.g. high, medium, and low layers of PVs) and crop-planting approach (with shade-tolerant crops under the PV panels and non-shade-tolerant crops between the PV panels) to improve land-use efficiency while also promoting mixed cropping and associated agricultural productivity and biological diversity benefits. Large areas of ornamental herbs and flowers were also planted to form colorful scenery in all seasons, providing ecotourism opportunities. The microclimate created by the shading effect of the solar panels and plants results in increased soil water storage, which ensured vegetation growth from 1% before AV system installation to 90% after, thus mitigating soil erosion and increasing soil fertility.
The agrivoltaics park in Jiangshan, China, before(left) and after (center, right) installation. Source: Xiao and others.
One project implementation challenge involved the one-off Farmland Occupation Tax, which is levied when agricultural lands are used for nonagricultural activities. The one-off tax was levied on the AV system ($145,863 at $5.47/m2) even though the land was degraded and still used for agriculture. This highlights the need to clarify regulations to differentiate conventional groundmounted PV installation from AV systems, as discussed in Section 5.2. The project was able to overcome the challenge of the profitability of the business model that incorporates multiple revenue sources from the same piece of land, supported by feed-in tariff policies that guaranteed revenue from generated electricity.
The Jiangshan AV park is expected to operate for 25 years and generate 4.9 billion kWh of power. The generated power will meet the annual electricity demand of 100,000 households in Jiangshan City. The project has created employment for 120 to 150 locals, benefitted nearly 1,000 farmers, and sustained local economic development. The park is expected to achieve an emission reduction of about 4.5 million tons of carbon dioxide and provide air quality benefits by preventing the emission of 140,000 tons of sulfur dioxide and about 70,000 tons of nitrogen oxides.
Case study 2: Harvesting the Sun Twice: an agrivoltaic pilot project in Tanzania.
Faced with significant energy security challenges, several East African countries have developed decentralized, small-scale mini-grid solar systems to tackle the problem. However, since the installation of mini-grid solar systems involves land clearance, current electrification strategies lead to ecosystem degradation. Funded through the United Kingdom Research and Innovation-Global Challenges Research Fund (£1.3 million), the Harvesting the Sun Twice project was designed to test the application and adaptation of AV systems in the East Africa region. The project sought to investigate the potential of AV technology to improve access to energy, increase household incomes by enabling the production of higher-value crops, and identify barriers to AV adoption in the semi-arid regions of East Africa.
The off-grid AV system used in the Harvesting the Sun Project improved access to electricity, generated higher crop yields, and reduced irrigated water use. Source: Dr Richard Randle-Boggis, University of Sheffield.
As part of the project, a 35 kW off-grid AV system, which includes rainwater harvesting and battery storage systems, was installed at the Sustainable Agriculture Tanzania agricultural training center in the Morogoro Tropical Savannah region. Several benefits were identified: (1) improved access to electricity; (2) higher crop yields for beans, Swiss chard, and maize compared to those under conventional production systems and (3) a 13.8% reduction in the quantity of irrigation water applied. The bean crop showed about 60% higher survival rate under AV than conventional production, suggesting that the AV system provided a protective environment that enhanced crop resilience to high temperatures, highlighting AV climate change adaptation benefits. A land equivalent ratio of 1.86 was observed, indicating 86% higher land productivity for AV systems. Results suggest the possibility of meeting energy and food security needs with fewer land resources.
However, onion, kale, sweet pepper,,r, and eggplant performed poorly under AV compared to conventional production systems. The observed yield reductions of these crop types may make AV unattractive for some farmers and thus constitute a barrier to AV adoption. These findings highlight the need to consider crop types and the specific local context when considering AV adoption.
During the stakeholder consultation process, representatives from the public and private sectors expressed interest in creating a conducive environment to support AV systems scaling. Energy provision through AV mini-grid systems is more attractive than expanding the national grid, as the former results in reduced energy transmission costs and losses. In addition, combining energy and crop production makes rural electrification possible without adversely impacting social cohesion, which could happen if land were taken from farmers for conventional solar farms. Amongst farmers, an appetite to adopt AV systems was expressed, but there was recognition that initial investment costs would be prohibitive for resource-constrained communities. Innovative financing mechanisms or business models would be needed to make AV adoption possible.
Case study 3: AV systems and smallholder farmers in Sitapur, India
Sitapur, a town in northern India, is characterized by a humid subtropical climate with dry winters. The region has been experiencing significant reductions in crop yields, partially due to poor rain distribution and high temperatures. Extreme weather events have reduced farm productivity and increased local food prices. Awareness about an AV project implemented by the Central Arid Zone Research Institute (CAZRI) elsewhere inspired Sitapur farmers to consider AV as a potential solution to their multiple challenges. Some Sitapur farmers worked with CAZRI to install small-scale AV systems using savings from rural government subsidies. One wheat farmer generated enough electricity to power three-night lamps and increase yields of seven more wheat tillers per square meter compared to the parts of the field without AV systems. The small-scale AV systems gave farmers an understanding of the benefits in the region, but they noted that scaling would require more financial and technical support, such as access to low-cost credits and knowledge and data sharing across AV systems in India to inform improved management in new and existing AV installations.
Source: OneEarth.org
CaseStudyy 4: The experimental and educational AV system at UNAM, Mexico
The Sustainable and Educational Agrivoltaic Platform is Mexico’s first AV system installation. Funded by the Ministry of Education, Science, Technology and Innovation and implemented by the Renewable Energies Institute of the Universidad Nacional Autónoma de México (UNAM), the experimental and educational platform aims to increase the quantity and enhance the quality of agricultural products, produce renewable energy, reduce freshwater consumption, create awareness, and build capacity for new technologies among agricultural producers. The AV system, which is part of an international consortium comprising research and educational institutions working on AV from Frane, Morocco, Israel, Kenya, Mexico, co and the United States,
will produce biomass for animal husbandry and food for human consumption. The AV installation covers an area of about 350 m2 with 72 solar panels positioned three meters above the ground. The generated power is expected to meet a significant portion of the center’s energy needs. The AV system includes rainwater harvesting with a storage tank of 145 m3 capacity and a drip irrigation system. The system also incorporates solar dehydrators for crop processing and preservation.
The experimental AV platform is funded by the Ministry of Education, Science, Technology and Innovation of Mexico City and implemented by UNAM’s Renewable Energies Institute. Source: UNAM
Case study 5: Agrivoltaics development in Japan
Japan boasts more than 3,000 small-scale agrivoltaics (AV) systems generating up to 600,000 megawatt hours of power annually, each occupying less than 0.1 hectares. A significant driver of adoption is the need for efficient land use due to limited arable land. In addition, government policies, such as subsidies and incentives to farmers, crop performance benefits, and opportunities for additional revenues, have encouraged widespread adoption. Regulations on land conversion have been clarified and provide an advantage to AV over conventional groundmounted solar PVs. The introduction of feed-in tariffs in 2012 also facilitated quick adoption, and a 2020 amendment to the feed-in tariff law preferentially favors AV systems over conventional PVs. AV systems are being positioned as a means of revitalizing Japanese agriculture, specifically for reclaiming degraded or abandoned farmlands. A notable barrier is the reluctance of elderly farmers to make the high investments needed, mainly because they do not have successors to take over their agricultural businesses.
AV systems at Chiba Ecological Energy in Japan. Image: Toru Hanai. Credit: Bloomberg.