Solar + Farming : New Paradigm in the Making

April 14, 2019

Fraunhofer Institute for Solar Energy Systems:

Over the past two years, the dual use of land for the harvesting of solar electricity and agriculture has been tested in the joint project “Agrophotovoltaics – Resource Efficient Land Use (APV-RESOLA).” On one-third of a hectare arable land near Lake Constance in Germany, photovoltaic modules with a total power output of 194 kilowatt are installed on a five meter high structure. The results from 2017 showed a land use efficiency of 160 percent, as confirmed by the project consortium under the direction of the Fraunhofer Institute for Solar Energy Systems ISE. The performance of the agrophotovoltaic system in the very hot summer of 2018 greatly exceeded this value. The partial shading underneath the photovoltaic modules improved the agricultural yield, and the sun-rich summer increased the solar electricity production.
In 2018, the farmers of Heggelbach, a Demeter farm community, successfully brought in their second annual harvest from the agrophotovoltaic system. Four types of crops were grown: winter wheat, potatoes, clover and celery. In 2018, the yields from three of the four crops grown under the agrophotovoltaic system were greater than the reference yield. The crop yields for celery profited the most by the system, with a gain of 12 percent compared to the reference. Winter wheat produced a gain of plus 3 percent and clover a minus of 8 percent. “Based on the 2018 potato yield, the land use efficiency rose to 186 percent per hectare with the agrophotovoltaic system,” says Stephan Schindele of Fraunhofer ISE.

Aside from the portfolio development, crop yield and quality, scientists of the University of Hohenheim collected data on the climatic conditions underneath the APV system and also from the neighboring reference field. The solar irradiation underneath the APV system was about 30 percent less than the reference field. In addition to the amount of solar irradiation, the APV system affects the distribution of precipitation and the soil temperature. In spring and summer, the soil temperature under the APV system was less than on the reference field; the air temperature was identical. In the hot, dry summer of 2018, the soil moisture in the wheat crop was higher than the reference field, while in the winter months, it was less, as for the other crops. “We can assume that the shade under the semi-transparent solar modules enabled the plants to better endure the hot and dry conditions of 2018,” says the agricultural scientist Andrea Ehmann. “This result shows the potential for APV in arid regions, but also the necessity to carry out further trials in other climate regions and with other types of crops,” adds her colleague Axel Weselek.

Cleantechnica:

For many people, solar power is seen as a threat to farming communities. That’s because they believe farmers must  choose between raising crops or livestock and installing solar panels on their land. The Fraunhofer Institute has been conducting experiments in what it calls agrophotovoltaics for two years near Lake Constance, Germany. In the first year, it found the combination of solar and agriculture made the land 160% more productive than if it had been devoted exclusively to one or the other.


2108 was one of the hottest years yet in Europe, with the high temperatures having a negative affect on the yield from many farms. Yet Fraunhofer’s Lake Constance experimental farm thrived. The shading provide by the solar panels actually increased the harvest and the extra sunshine boosted electricity output as well. “Based on the 2018 potato yield, the land use efficiency rose to 186% per hectare with the agrophotovoltaic system,” says Stephan Schindele of Fraunhofer ISE in a press release.

The Lake Constance farm mounts its solar panels 5 meters above the ground, leaving room for livestock and plants to grow and conventional farm equipment to operate beneath the them. In comparison to open fields in the area, solar irradiation beneath the panels was about 30% less, the air temperature was identical, but soil temperatures in the spring and fall were lower.
In the hot, dry summer of 2018, the soil moisture in the wheat crop was higher than the reference field. “We can assume that the shade under the semi-transparent solar modules enabled the plants to better endure the hot and dry conditions of 2018,” says the agricultural scientist Andrea Ehmann. “This result shows the potential for APV in arid regions, but also the necessity to carry out further trials in other climate regions and with other types of crops,” adds her colleague Axel Weselek.
Food vs Fuel
Producing electricity on a farm has other economic benefits as well. Equipment manufacturers like Fendt and John Deere are starting to introduce electric tractors and other farming equipment. In combination with local battery storage, a farm can become energy independent. “When politics allow, agrophotovoltaics can provide the answer to the ‘food or fuel’ debate. From the technical point of view, farmers can harvest both. Through the dual use of arable land, the main task of food production is met. The additional solar electricity production contributes to the expansion of electric mobility and serves to protect the climate,” Stephan Schindele says.

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6 Responses to “Solar + Farming : New Paradigm in the Making”

  1. rhymeswithgoalie Says:

    Looks fantastic for some crops and applications. One caveat: Current automated farm machinery, responsible for a lot of improved efficiency in recent decades, would not work in that configuration.

  2. rhymeswithgoalie Says:

    That’s because they believe farmers must choose between raising crops or livestock and installing solar panels on their land.

    After seeing so many cattle in treeless pastures on hot, sunny days, I’d like to see more “covered parking” made available to them in the guise of solar panel stands.

    • Earl Mardle Says:

      My first thought as well. Since I arrived on my place we have been planting trees, some of them to provide shade and shelter for animals in otherwise bare paddocks.

      At the very least farmers should be looking at covering the roofs of their utility buildings with PV. I have only a 10 acre block but it has 2 barns and a house with at least half of each building suitable for PV. Commercial farmers will; have much more roof space to offer, even before they touch the paddocks.

      I’d like to see the economics as well, running cabling under arable land will mean reasonably deep trenches and heavy cable. Plus 5m structures capable of withstanding the winds that will come with climate change will not be cheap.

  3. dumboldguy Says:

    Some completely good news for a change!!! WHOOPEE!

    Although at first it seems counter-intuitive to put shade over crops, the fact that soil temperature is lower and soil moisture is conserved and increases yields makes it a positive thing, and using the electricity to power EV farm equipment is a nice touch.

  4. Brent Jensen-Schmidt Says:

    With rising temperatures, there will be more advantages to some shade. My SHTF doomsday garden was wiped out by one day of extreme (extremiest) weather. Working on it.
    If the Sun was the only climate driver, every where on the same latitude would have the same weather. And a colder climate at present solar output.

  5. redskylite Says:

    UK’s National Grid operator gets ready for 100% renewables by 2025

    “National Grid, the operator of the UK electricity system and the equivalent to the Australian Energy Market Operator, says it is preparing to change its systems so it can operate the electricity grid with 100 per cent renewable energy by 2025.”

    National Grid says there soon will be times in the year when the market could meet the total demand for electricity through renewable generation only and these periods will increase as more and more renewables are connected and more load actively participates in the market.

    “This is very different to the traditional model of power system operation and, to enable all of this low-carbon generation operate unconstrained, requires us to address and solve some critical engineering challenges,” it says.

    https://reneweconomy.com.au/uks-national-grid-operator-gets-ready-for-100-renewables-by-2025/


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