The utility company Erdgas Südwest GmbH from Ettlingen near Karlsruhe and the gravel plant operator Ossola GmbH are jointly building the largest photovoltaic system floating on a quarry pond in Germany to date . The Maiwald quarry pond belongs to the municipality of Renchen near Achern and is situated between Offenburg and Baden-Baden. Although the system will cover only about 2% of the pond’s surface, it is expected to supply around 800,000 kilowatt hours of electricity per year. The energy will primarily be used in Ossola GmbH’s gravel plant - owner of the quarry pond. Several excavators, crushers and conveyor belts operate there, consuming a lot of electricity. They are expected to consume two thirds of the energy generated by the plant, with the remainder being fed into the public grid.

According to Erdgas Südwest, quarry ponds are particularly well suited for power generation, as the floating photovoltaic systems do not compete with other uses there. An additional yield of around 10% can be expected thanks to the water’s cooling effect.