District Heating Supply as Exemplified by the City of Mannheim.

After the war the district heating supply system already started some years earlier for the industrial area in the southern part of the city was extended by the large Mannheim power plant (GKM). Steam, which is drawn off from the corresponding bus system at the GKM, serves as the heating medium at a pressure of 20 bars. The enlargement of the city heating system commenced in 1959. Within a few years, a comprehensive district heating network had been developed by the Mannheim municipal authorities. In 1961, a 30 MW back-pressure turbine was installed in power station No. 1 at the GKM in place of an old condensing turbine; this heats up the district heating water in two stages. The thermal output amounts to 120 MW. An additional peak coverage up to 160 MW is given by the 20 bar bus system. In October 1982, a new heating power plant unit with an electrical and a thermal output of 450 MW each was commissioned.