In local heating networks, a large number of consumers obtain heating coverage and hot water supply from a single source. An operator arranges fuel purchasing, fault-free operation and maintenance of the heating centre. The grouping together of users as one large consumer and the professional operational management bring technical and economical advantages which are more important than the extra user comfort gained.

Technologies can be used which are too expensive or large for individual consumers, e.g. cogeneration, woodchip burning and waste heat utilisation. Compared to individual systems, it is possible to react better to changed framework conditions and potential energy savings can be tapped cost-effectively with modernisation measures at a central location. Local heating networks offer particular opportunities for the incorporation of solar energy, because the specific costs per m² of collector surface area are lower than with several smaller solar energy systems on each of the individual buildings. In addition, it is possible to supply solar energy to buildings which otherwise have no possibilities for utilisation of solar energy. A demonstration system on the North Sea island Norderney shows how a solar energy system can be retrofitted into an existing local heating network.

Here, since 2002, a heating centre housed in Wirtschaftsbetriebe Norderney's building materials depot supplies heat to the local residential and commercial buildings. In summer 2007, the operator integrated a solar energy system into the return line of the "Gorch-Fock-Weg" local heating network. It was planned to cover around 17% of the connected settlement's heating requirement with solar heat.
The planners placed particular emphasis on a system design which was as simple as possible and on a clear control strategy. This was to guarantee high availability and operational reliability, also in the period after the intensive measurement phase. Special attention was also paid to the island climate, as the system will have to cope with high wind loads and a corrosive marine climate over the years. The German Federal Ministry for the Environment funded the project as part of the Solarthermie2000plus research programme. The results of a one-year measurement phase are now available.