Bavarian hop farmer installs solar panels above plants to reduce heat stress

A hop farmer in Bavaria has installed photovoltaic modules seven metres above his plants to reduce heat and retain soil moisture. Josef Wimmer operates one of 722 hop farms in the Hallertau region, which accounts for most of Germany’s 904 hop-growing businesses. He said the years have become hotter and drier, prompting him to seek ways to protect the crop.

Pilot installation Wimmer worked with engineer Bernhard Gruber, a former Airbus employee, to design and build the system. The first phase covers five hectares and generates two megawatt peak of electricity. Gruber adjusted the panel tilt after an initial test showed that excessive shade reduced cone production.

The revised layout balances energy output with the shade needed to keep soil moist during June, July and August. Wimmer plans to extend coverage to 20 hectares within two to three years, adding eight megawatt peak of capacity and one megawatt of battery storage.

Planning and approvals The project required nearly two years to obtain a building permit. Wimmer also paid for a five-kilometre cable to connect the system to the substation. Gruber said lengthy approval processes discourage other farmers from adopting similar installations on a larger scale.

Wimmer reported that soil moisture has increased under the panels because evaporation has decreased. He said the change benefits the hops during the driest summer months.