Dollnstein is a small community with about 2,700 inhabitants in the heart of Bavaria, Germany. Dollnstein is located in the Altmühltal Nature Park, one of the most popular touristic destinations in Bavaria.A combined heat and power plant (CHP) and photovoltaic power plants supply the electricity for the thermeco2 machine and the pumps in the households. In an intelligent system, the heating centre, heating network and consumer are connected to each other – including power supply of the consumer stations.