Solar heat is also important in the future energy mix. The number of solar thermal systems can be significantly expanded, the average solar share of the heat demand coverage for buildings or districts can be further increased, and previously untapped application areas should be systematically developed. Until now, broad-based subsidy programmes have mainly concentrated on solar thermal heating systems in single- and two-family houses, where the majority of the solar collectors are used. The considerable potential in the rental housing sector, hotels, hospitals, old people’s homes, commercial enterprises as well as in housing estates and commercial areas has hardly been tapped. And this despite the considerable advances in the technology.
Solar-assisted local heating provides the entry into a permanently sustainable heat supply for larger properties or even entire districts. However, its technical implementation still often represents uncharted territory for many stakeholders and incurs more additional costs compared with conventional local heating systems.
Various research projects are focussing on the decentralised feed-in of solar heat in local and district heating networks as well as on new multi-pipe networks for supplying heat at the district level. This will enable not only heat to be supplied centrally but will also enable heat produced locally from renewable energies to be fed into the grid in a decentralised manner.