Farming and solar power are often portrayed as competing for land resources, but the two are increasingly expected, with the right policy support, to occupy the same space. Pilot projects show how such co-existence can be mutually beneficial, boosting clean energy production and crop yields
Land use
: Land the world over is in limited supply and constantly faces a plethora of demands. Producing food and renewable energy in the same space would help alleviate some of this pressure
Win-win:
Test projects in Germany and Tucson in the US reveal placing solar panels and crops in the same fields can boost yields and increase energy output
Key quote:
“If both the benefits for agriculture and energy are taken into account, the global returns are higher and land use is also optimised”
A pilot agro-energy project near Lake Constance, on the border of Germany, Austria and Switzerland, is in its third year of producing celery, wheat, potatoes, clover and solar power. Spearheaded by the Fraunhofer Institute for Solar Energy Systems, the 194 kilowatt agrophotovoltaic (APV) system in a farming community in Heggelbach, Germany features photovoltaic (PV) panels raised eight meters above the ground and crops below. The project shows that agriculture and energy production can be effectively combined. Results from the last harvest, in the hot summer of 2018, were particularly encouraging. Yields from three of the four crops below the PV panels were higher than those in an adjacent reference field that only produced crops. Celery and potatoes benefited the most, with a yield about 12% above the reference yield, while at the other end of the spectrum, clover’s yield was 8% below the reference. The APV system also produced 249,857 kilowatt hours of electricity, leading to a land use efficiency ratio for that year of about 186% per hectare, says Fraunhofer ISE. That compares with a benchmark of 100% for land occupied either by crops or PV alone. “One big motivation for us to take part in the project was to show there is a different way of doing photovoltaics where you can have the co-existence of energy and food production,” says Albert Schlaak, project manager at BayWa r.e. Solar Projects, which oversaw the technical aspects of the Fraunhofer ISE pilot. “As a developer, we can have a problem with acceptance if we are seen as grabbing land from farmers, but it can be hard to maintain agriculture on a normal PV site.” On a traditional PV site, designed to maximise power production, panels are mounted close to the ground and the distance between lines of panels is reduced, significantly increasing shading and making it impossible to use agricultural machinery. Combining food and energy production on the same site will increasingly be obligatory in the face of land scarcity, believes Dirk Vansintjan, president of REScoop.eu, a European federation of renewable energy cooperatives. It is involved with a project proposed by a Boerenbond, a Belgian farmers association, to create rural energy cooperatives in northwest Europe. Vasnsintjan believes APV will develop first where the shortage of land is felt most keenly and policymakers are serious about ambitious renewable energy targets, as well as when there is a need to protect crops.
Multiple benefits
Crop protection is one of the potential benefits of APV systems. “With APV, crops and top soils are better protected from unexpected adverse weather conditions such as heavy rain and hail,” says Maximilian Trommsdorff of Fraunhofer ISE. APV could also increase the suitability of arid regions for agriculture. “The shading effects of semi-transparent solar modules enable plants to better endure hot and dry conditions potentially leading to higher and more stable agricultural yields,” says Trommsdorff. Reducing water requirements is another advantage, he adds, stating that while the potential of APV is significant globally, it tends to be greater in hot, sunny regions. Researchers at the University of Arizona in the dry, desert climate of Tucson in the US have found that combining photovoltaics and agriculture leads to higher crop yields, reduced water use and benefits the production of energy, with plants cooling the solar PV panels and allowing them to operate more efficiently. APV could also improve the business case for farmers in many parts of the world suffering from fluctuating commodity prices and increasingly unreliable weather patterns because of climate change, allowing them to keep producing food. The opportunity to stabilise income and actually help plant growth at the same time means they are likely to be open to innovation, says Jan Rongé, a bioscience researcher with KU Leuven university in Belgium and part of a multidisciplinary team looking at APV. 
The battery is designed to increase the farm’s self-consumption
Policy needed
Despite potential advantages, policies are still lacking in many places to encourage the use of APV. That is the case even in Germany, the European frontrunner in solar PV installations. “There is currently no innovation incentive to support an APV system in Germany,” says Schlaak. In fact, German farmers are discouraged from using APV as they may lose agricultural subsidies and would need to be compensated in PV land lease agreements, meaning that there is no business case. The pilot project in Heggelbach also served to raise awareness of the technology’s potential with politicians, states Schlaak. Others are further ahead on the policy front. In neighbouring France, invitations have been issued to tender for APV innovation projects. In the US, the state of Massachusetts has sought to encourage what it calls dual-use farming. Under the state’s incentive system, qualifying “Agricultural Solar Tariff Generation Units” receive an additional $0.06 per kilowatt hour above the base solar tariff. And in Japan, the government in 2013 issued guidelines for solar PV development on agricultural lands, known here as “solar sharing,” allowing for farmers to produce electricity as long as farming continues and crop yields remain at 80% of their annual average. 
The agrophotovoltaic system in Heggelbach near Lake Constance in Germany
Costs
Given it is a relatively new technology and APV structures must rise further above the ground, it is not surprising the systems cost more than traditional ground-mounted PV. Fraunhofer ISE calculates the generation price from its APV system in Heggelbach is about €0.115 a kilowatt hour versus about €0.07/kWh for a conventional ground-mounted system. The higher cost is already almost comparable to rooftop installations, however, and should fall as APV develops globally and economies of scale kick in. In turn, the increased cost-efficiency of traditional ground-mounted PV systems is expected to increase the demand for land. “If both the benefits for agriculture and energy are taken into account, the global returns are higher and land use is also optimised”, stresses French renewable energy developer Akuo Energy, which has been combining agriculture with PV for the past decade. The company says these projects can also help farmers financially, facilitating a transition to organic farming which otherwise might be too costly. The Food and Agricultural Organization (FAO) is just one voice advocating the use of organic agriculture to contribute to reducing the sector’s greenhouse gas emissions through avoiding the use of synthetic fertilisers and pesticides and increasing the carbon sequestration capability of soil. Rongé says politicians in Europe tend to focus on installing solar on rooftops, but believes APV will be an essential part of the continent’s renewable future. “If you look ahead only to 2025 or 2030, you could think agrophotovoltaics is not required, but in 2050 there will be a need for lots more land and it will be absolutely necessary.”
TEXT
Heather O’Brian
PHOTO
BayWa r.e.