Uniper operates 35 run-of-river power plants on the River Main, which have a total capacity of around 119 megawatts and generate around 0.7 billion kilowatt hours of environmentally friendly electricity per year. This is enough to supply around 247,000 private households with electricity and save around 428,000 tons of the harmful greenhouse gas CO2.

Uniper supports the goals of the EU Water Framework Directive from 2000, which focus on the good ecological condition of flowing waters. This includes, above all, the upstream passage of fish and other river life past weirs and power plants.

Uniper also supports upstream river continuity on the Main. In addition, Uniper also enables the downstream migration of eels through intelligent control using MIGROMAT®, as in Erlabrunn, Hausen, Heubach, Kesselstadt, and Garstadt. In addition, around 10,000 eels (approx. 6 tons) are caught on the Main River by fishermen on behalf of Uniper every year under the title "Catch & Carry", collected and transported to the Rhine for onward migration. All this is always done in close coordination with the local authorities and the Free State of Bavaria.