Extended use of district heating systems contributes to an optimal utilization of primary energy by decentralized combined power and heat generation. Utilizing more than 80 percent of the total fuel energy, this process contributes towards minimizing the total energy consumption, although shifting the fuel consumption, depending on the degree of utilization of the respective fuels, to the higher-grade hydrocarbons, which should be the first to be substituted. With the emission of waste gas and noise under control by mechanical and structural means, it is possible to locate installations near the centers of consumption and to construct small district-heating systems low in preliminary investment so that they correspond to the consumer potential. A high-capacity power system should be available to compensate electricity shortfalls. The electricity supply undertaking should at the same time operate the combined district-heating and power plant.