Biogas can easily be produced with material that cannot or only very difficultly be exploited otherwise: Organic waste, manure, rests of plants. Producing biogas does not necessarily need a vast corn crop growing activity. Corn is food and needed as that. We show examples in the surroundings of Freiburg where the produced gas is often used very near to the production place. It is in some space also cleaned so that it can be injected into the natural gas grid.