Engineering

Double Harvest: Power & Salad from the same field

Now is Germany’s first industrial plant in operation, on the solar energy harvested and grown food. The modules are mounted so high that harvesters under them can drive. Up to 50 gigawatts could be installed without losing acreage.

On a 3500 m2 large field of the Demeter farm community Hegen Gelbach in twelve kilometers north of the farming harvest the in Thomas Schmid property and his colleagues in the future electricity and vegetables or salad.

power-salad-from-the-same-field
A prototype of the APV system was installed in March 2016. The findings have been incorporated in the final design and design of the research facility. Photo: Fraunhofer ISE

It is the first big Agro photo-voltaic (APV) in Germany. It will be inaugurated on September 18. The solar modules are mounted on stands that are so high that harvesters can pass through easily. The distance between the module rows is 3.5 m greater than usual, including growing the plants to allow enough sunlight.

Enough electricity for 50 homes from agro-photo-voltaic plants

The silicon solar cells have a peak output of 194 kW. They produce per year nearly 200,000 kWh used in the village itself. Excess flow into the public power grid. The power is enough to supply about 50 average households. “We had to leave something out, so that it works with the energy revolution”, says Winfried Franke, Director of the regional association of Bodensee Oberschwaben, where the districts of Ravensburg, Bodensee, Constance and Sigmaringen are joined together.

Enough electricity for 50 homes
Enough electricity for 50 homes, 1) Power Plant, 2) Consumers, 3) Power grid 

Together with researchers from the Stuttgart University and the Fraunhofer Institute for Solar Energy Systems (ISE), he took up an idea formulated by Professor Adolf Goetz Berger, the founder of ISE, in the 1980s. He wanted to reconcile with each other agriculture and solar energy.

So far, arable land is lost with every major photo-voltaic system. The spaces can be used as pasture by sheep or goats. The combination of meets now both interests.

Some plants love shadow periods

ISE researchers have previously simulated as the system must be aligned when she should bring optimal harvesting and electricity yields. It works best if the module rows from southwest to Southeast. Then, the crops are shaded although at times. The agricultural of University of Hohenheim took out power but nothing. Some plants grow even better.

ISE researchers Stephan Schindele believes that Agro photo-voltaic in Germany has a huge potential. Between 25 and 50 GW could be installed Additionally without farmland is lost. Well 40 GW solar energy to the network are currently in Germany. 52 GW are target of the Federal Government in the year 2020. “This approach, to use solar power on the same surface, for crops and solar electricity production could evolve into a world’s interesting example”, says Professor Eicke R. Weber, Manager of the ISE.