Agrivoltaics: When Solar Power Meets Agriculture

The concept of agrivoltaics dates back to the early 1980s when German physicist Adolf Goetzberger first proposed combining agriculture and solar energy production to address land scarcity, food security, and increasing energy demand. 

Over the years, agrivoltaics has evolved into a promising solution that addresses various global challenges while offering significant benefits to agriculture, such as increased land use efficiency and water savings. 

Special thanks to David Ceaser and Christian Kanlian from Agritecture for providing their valuable insights into the origins, evolution, and concerns surrounding agrivoltaics, shedding light on the achievements and obstacles in its implementation.

The Origins and Evolution of Agrivoltaics from Adolf Goetzberger's Vision

The origins of agrivoltaics can be traced back to the early 1980s when concerns about land scarcity, food security, and increasing energy demand started to gain prominence. At the time, solar energy emerged as a viable alternative to conventional fossil fuels. As a result, scientists were exploring innovative ways to integrate renewable energy production with traditional land use practices. Adolf Goetzberger, a German physicist and solar energy pioneer, was among the first to propose combining agriculture with solar energy generation, thus giving birth to agrivoltaics in its 1981 paper published in the International Journal of Solar Energy with Armin Zastrow.

Agrivoltaics, also known as agrophotovoltaics or solar sharing, was conceived as a solution to the dual challenge of producing sufficient food and energy for a rapidly growing global population while preserving the planet's limited resources. Goetzberger envisioned that integrating solar panels with agricultural land could lead to better land utilization, increased efficiency in energy production, and minimal disruption to agricultural activities. As a result, research and experimentation in agrivoltaics began to gain traction, leading to the development of various configurations and approaches that maximized the benefits of combining food production with renewable energy generation. Over the years, agrivoltaics has evolved into a promising solution that addresses the pressing issues of land scarcity, food security, and climate change, with its roots firmly grounded in the visionary work of Adolf Goetzberger.

According to Adolf Goetzberger's work, several essential criteria must be considered before classifying a system as agrivoltaics:

1. There must be a seamless integration of solar energy production with agricultural activities, ensuring neither is compromised.

2. The configuration should optimize land use efficiency by maximizing food production and energy generation within the same area.

3. The system should prioritize sustainability, minimizing environmental impacts, such as soil degradation, water consumption, and biodiversity loss.

4. The agrivoltaic system should demonstrate a synergistic effect between agriculture and solar energy production, providing benefits beyond each component's outputs.

The Impressive Growth The Solution Witnessed Over The Years

As the demand for renewable energy and sustainable land use practices increases, the correlation between the expansion of photovoltaics and agrivoltaics becomes more evident. For example, global solar capacity doubled in 3 years from 2018, bringing the world's solar fleet to one Terawatt capacity in April 2022, according to SolarPower Europe, showcasing the rapid adoption of photovoltaic technology. On the other hand, the Food and Agriculture Organization (FAO) highlights that global agricultural land has remained relatively constant at around 4.9 billion hectares since the early 2000s, emphasizing the challenge of efficiently utilizing available land resources.

Agrivoltaics offers a potential solution to this challenge, combining solar energy generation and agriculture on the same land. While comprehensive global data on agrivoltaic installations is limited, numerous pilot projects and research studies worldwide have demonstrated such systems' potential benefits and synergies. For instance, a 2018 study by the Fraunhofer Institute for Solar Energy Systems in Germany reported a 60% increase in land use efficiency by combining solar panels with crop cultivation. These findings, coupled with the growing interest from governments and stakeholders, indicate a positive correlation between the expansion of photovoltaics and the adoption of agrivoltaic practices. However, it's important to note that the scale and impact of agrivoltaics will vary across different regions and contexts.

Indeed, according to David Ceaser & Christian Kanlian from Agritecture, "The most widespread use of agrivoltaics is in Japan, where as of 2021, there were nearly 2,000 farms with agrivoltaic setups. This is because Japan suffers from a high rate of farm abandonment due to poor economics and aging farmers, and the incorporation of agrivoltaics once again makes using this land profitable." 

Solar and energy companies have increasingly recognized the value of partnering with farmers to utilize agricultural land for solar installations, often offering them higher revenue per acre than traditional farming practices generate. This additional income can attract farmers, who may face volatile commodity prices, unpredictable weather, and challenging market conditions. By leasing their land to solar companies to install photovoltaic panels, farmers can secure a stable, long-term income stream that is less susceptible to the risks associated with agricultural production. Solar developers often enter into long-term lease agreements, offering farmers a fixed rate per acre or a percentage of the revenue generated from solar installation. This financial incentive benefits the farmers by supplementing their income, supporting renewable energy growth, and contributing to climate change mitigation efforts.

For example, Energy News US published an article in 2017 stating how companies such as Strata Solar would lease land from the farmer and pay anywhere between $700 to $1100 per acre per year, which often represented two to three times more than what the farmer would generate from selling wheat or soybeans spiking ethical concerns on how farmers may want to focus more on yielding passive income.

Balancing Land Use Concerns & Benefits

Agrivoltaics offers a unique approach to addressing the increasing global demand for renewable energy and food production. However, some concerns must be considered to present a balanced view of this innovative land use practice. One of the main concerns is the potential impact on agricultural productivity (Mamun et al., 2022). While research has demonstrated that certain crops can benefit from partial shading provided by solar panels, the effects on overall crop yield may vary based on crop type, panel configuration, and regional climate (Dinesh and Pearce, 2016). As such, assessing these variables on a case-by-case basis is essential to ensure that agrivoltaic systems do not negatively impact agricultural output.

David Ceaser and Christian Kanlian state, "The Japanese agrivoltaic system has benefits and challenges. Japan suffers from a high rate of farm abandonment due to poor economics and aging farmers, and the incorporation of agrivoltaics makes using this land profitably. However, the main challenge of agrivoltaics in Japan is that it causes most farm operators to convert to a different crop due to increased shading. This can have downstream impacts, such as affecting the diets and economies of local communities. In Europe, two central agrivoltaic systems are being pursued, with one system designed to integrate crops such as wheat and soybeans. These alternate systems have rows of solar panels and crops, with the crop row being wide enough for all tractors and other equipment to pass through easily."

Another concern relates to the potential environmental impacts of large-scale agrivoltaic installations. Introducing solar panels into agricultural landscapes may disrupt ecosystems, alter the natural habitats of various species, and impact soil quality. However, it is essential to note that these potential consequences can be mitigated through careful planning, site selection, and adopting the best solar panel installation and land management practices. By considering the environmental impacts and conducting thorough research, stakeholders can work together to create agrivoltaic systems that balance the need for renewable energy generation and agricultural land use in a sustainable manner.

"The secondary effects of agrivoltaic systems are not well known at this time, but they increase shading, reduce ground temperatures and reduce evaporation, all of which lead to changes in the plant and animal communities in the area. If the same crop is being produced as before the agrivoltaic integration, then those changes to biodiversity will be minimal. However, switching crops due to agrivoltaic integration could change the insect species interacting with said crop and influence other interactions, such as birds. For soil health, the overwhelming assumption is that agrivoltaics will result in positive impacts, especially in historically dry locations, but the opposite could be true in wet locations. Suppose you are worried about the potential implications of incorporating this technology into your farm. In that case, it is recommended to incorporate agrivoltaics onto a small portion of your crop area and test it for a couple of seasons to see how it performs vs. your current production system." Commented David Ceaser & Christian Kanlian.

A notable benefit of agrivoltaics is its impact on crop growth and water usage. Research has shown that partial shading provided by solar panels can help some crops grow more efficiently under certain conditions. For example, a study conducted in 2019 by the University of Arizona found that certain crops like tomatoes, chiltepin peppers, and jalapenos showed higher fruit yield and water use efficiency under agrivoltaic systems compared to traditional open-field cultivation. The shading from the solar panels reduced evapotranspiration rates, helping plants retain moisture and reducing water requirements. This is particularly beneficial in arid regions or areas where water scarcity is a concern, as it contributes to more sustainable agricultural practices and improved resource management.

Overcoming The Limitations Of Lithium Batteries 

The use of lithium batteries for storing solar energy has become increasingly popular due to their high energy density, long cycle life, and declining production costs. However, a critical analysis of lithium battery technology reveals some concerns and challenges that need to be considered alongside their undeniable benefits.

One significant concern with lithium batteries is sourcing raw materials required for production. Lithium and other metals such as cobalt, nickel, and manganese are necessary for manufacturing lithium-ion batteries. However, the extraction of these metals raises environmental and social issues, as the mining process can lead to habitat destruction, water pollution, and greenhouse gas emissions (Flexer, Baspineiro and Galli, 2018). Moreover, some regions where these minerals are abundant, particularly cobalt, have been linked to unethical labor practices and human rights violations (Sovacool, 2021). To address these concerns, efforts are being made to develop more sustainable mining practices, increase the recycling of lithium batteries, and explore alternative chemistries that reduce the reliance on these scarce resources.

Another issue with lithium batteries is their inherent safety risks. Lithium-ion batteries are susceptible to thermal runaway, a chain reaction that can lead to overheating and, in some cases, fires or explosions (Wang et al., 2012). This risk is usually mitigated by incorporating safety features such as thermal and battery management systems. However, high-profile incidents involving lithium battery fires in electric vehicles and consumer electronics have raised concerns about their safety. As a result, researchers are actively working on improving the safety of lithium batteries by developing new materials, designs, and chemistries that minimize the risk of thermal runaway.

Finally, the disposal and recycling of lithium batteries present additional challenges. As the adoption of solar energy storage and electric vehicles expands, the number of spent lithium batteries will increase accordingly. Currently, only a tiny fraction of lithium batteries are recycled, with the majority ending up in landfills or incinerated, which can result in environmental pollution and the loss of valuable materials (Swain, 2017). To address this issue, it is crucial to establish efficient recycling processes and infrastructure and encourage regulatory policies that promote the responsible disposal and recycling of lithium batteries. 

David Ceaser & Christian Kanlian remain optimistic as they see emerging renewable batteries that, in some cases, can improve energy storage compared to traditional lithium. "Numerous energy storage solutions are being explored to address the intermittency of solar and wind energy production, with green ammonia and hydrogen as leading candidates. Green ammonia and hydrogen can be produced from atmospheric air using renewable energy, making them environmentally friendly alternatives. Compared to hydrogen, ammonia offers more dense and stable energy storage due to its chemical structure (Fasihi et al., 2021). When produced using renewable energy sources, these gases are labeled "green," while those produced using mixed grid or fossil fuel energy are called "blue." FuelPositive is an example of a prominent green ammonia company. These gases are condensed under high pressure, enabling denser and more stable energy storage than advanced batteries. However, large-scale battery storage may not be feasible at the grid scale, even with developments in solid-state batteries and other technologies."