The Heggelbach agrivoltaic site and Fraunhofer ISE results

The Heggelbach agrivoltaic system in southern Germany recorded land use efficiency of 186% in 2018, against 160% in 2017. It has 194 kW installed over one third of a hectare, on a five-metre-high structure, under the APV-RESOLA project.

The Fraunhofer ISE release of 12 April 2019 sets out the detail: the 186% rests on that summer's potato harvest, in an exceptionally hot year. Of the four crops, celery yielded 12% more than the reference, winter wheat 3% more and clover 8% less. Irradiation under the modules was about 30% below the reference field.

The same release places the cost: electricity from the agrivoltaic system is competitive with a small solar rooftop. That puts the arrangement in a cost band above ground-mounted plants, because the elevated structure and the clearance for machinery sit in the capex.

That band decides who pays. The project closes when the electricity displaces a tariff at the farm itself, or when the crop underneath carries enough value to fund the structure. In Brazil, irrigated fruit and horticulture meet both conditions, and that is where agrivoltaics enters before it reaches grain.