“Agrivoltaics combines agriculture with energy efficiency while growing plants beneath solar panels.”

By Linn Smith

January 28, 2018—- Co-location means two or more groups, sharing the same place. Agrivoltaics, also known as Agrophotovoltaics, means using the same piece of land for solar power plus agriculture. Agrivoltaics, or solar farming, is a new way of growing plants, combining agriculture with energy efficiency while growing plants beneath solar panels.

Agrivoltaics: Dual Use of Land

In 1981, Adolf Goetzberger and Armin Zastrow developed the idea to improve overall production of crops. Dr. Goetzberger founded the Fraunhofer Institute for Solar Energy Systems in Germany. His work involved making solar an alternative to fossil fuels. In 1981, he published a paper titled, “Potatoes under the Collector,” which proposed a setup for solar energy systems in combination with agricultural land use.

Dr. Eicke Weber, Director of the Fraunhofer Institute stated, “In view of the dynamic worldwide growth of solar installations of the last decade and the increase in land usage resulting from solar installation systems, innovative concepts, like agrophotovoltaics (agrivoltaics) which facilitates the dual usage of agricultural land, help to further and accelerate the transformation of the global energy system.”

Dr. Goetzberger used the term Agrophotovoltaics or APV, as a method of harvesting the sun for both power and production of crops. APV is currently an ongoing project in Germany which demonstrates that land for both growing crops and solar electricity are compatible. Dual use of the land is resource efficient, reduces competition for land and opens up a new source of income for farmers.

The APV System

The APV system was installed on organic farmland in Germany in 2015. Approximately seven acres were used to produce crops under the ground-mounted solar panels, which were built about 5 yards off the ground. Four different crops were planted. The land in use not only generates electricity from the solar panels but is also growing food. The solar panels provide a uniform light distribution on the crops using reflection. To prove their theory, they also planted a control plot nearby using the same 4 crops, excluding the solar panels. The scientists wanted to determine which crops would grow best. Result: The crops under the APV system produced about 80% of that of the control crop. This experiment is ongoing and data will be analyzed in 2018.

Agrivoltaics and Biosphere2

A similar experiment was being conducted at Biosphere2 when I visited several weeks ago. This research, headed by Barron-Gafford, Assistant Professor, revealed that the solar system above the crops created a warmer environment than normal when no plants were beneath , similar to the heat-island effect that happens in cities surrounded by cement and asphalt. He stated, “So think about it, if you get rid of all the plants when you put in renewables energy, you’ve gotten rid of that cooling potential… plants under the panels would allow the air to circulate and would take up carbon for photosynthesis by opening up their pores, or stomata, while letting water escape from their leaves and you get a warmer environment. We wanted to see if you put the cooling effect back into the system by growing plants beneath the solar panels, you can actually cool those panels back down and mitigate that heat island effect.”

When solar panels get too warm they start to lose their efficiency. By growing plants beneath the panels they can cool down and retain that efficiency, which makes for more renewable energy per parcel of land. The panels also shade the plants, reduce evaporation and the crops require less water to grow underneath.

In the future, as world population grows, solar and land for food must not be in competition. The world population today is approximately 7.6 billion. Two hundred years ago it was 1 billion. At the close of the 21st century the population will be more than 11 billion. The question remains…will we be able to feed our planet’s population and meet the demand for clean energy?

Agrivoltaics and Clean Energy

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