Survey of Existing District Heating Systems

The basic aim of the survey is to determine the state of development and planning of these types of district systems. In the western world, there is a wide variance of capacity, but it can be stated generally that those countries that developed systems early have a substantial lead in technology. Development in the eastern bloc is largely parallel to that of the west in that most work has been undertaken during the post-war period. World events have played their part, notably the oil crisis of 1973, which has led to more rational energy policies and usage, in addition to the consideration of alternative primary fuel sources. While this quest for other energy reserves continues, most countries are turning to indigenous fuels. This, of course, leads, wherever possible, to partial fuel independence, a state that is more pronounced in the eastern bloc. At present, the Federal Republic of Germany has the largest connected public system in the west, although in terms of megawatts per thousand inhabitants, Scandinavia comes out ahead. Obviously, information from eastern Europe is difficult to obtain, although it is known that substantial district heating systems are in existence in the bloc. As far as heat production is concerned, there are two systems:

1. dual-purpose, where a power station (nuclear or conventional) produces heat as by-product in the generation of electrical energy
2. heat-only, where the production of heat energy is the primary purpose.

In terms of economic feasibility, a local nuclear power station could be more efficient than a conventional station, when dual-purpose stations are considered. Quite obviously, present and future usage and development depend on several important factors, including geographical location, influencing climate, local supply, and political considerations. At the present time, western development is limited mainly to preliminary studies and the consideration of one of the most important basic questions, that covering the role of nuclear energy in district heating systems.