Lessons Learnt from Innovative but a not Realised Project on Geo-Solar District Heating

Fulltext: For the new housing area ""Zum Feldlager"" (approx. 130 low energy residential houses), located in Kassel (Germany), various supply concepts are investigated. Main objective is the development of an innovative and optimised heat supply concept based on renewable energies and a low temperature district heating.A promising heat supply concept is based on a central ground source heat pump in combination with a low temperature district heating (40°C supply temperature) for space heating and decentralised solar thermal systems for domestic hot water preparation. The advantages of this supply variant are comparable low annual heating costs and about 60% lower CO2-emissions in comparison to the reference system (gas condensing boiler with solar thermal system).Due to time and other constrains it was decided not to realise the above mentioned energy concept. The presentation will focus on the issue how to overcome these barriers and to be able to realise more good, innovative and future save heat supply systems. However, the research project took up the task to investigate the transferability of the concept in technological and economical perspectives to other locations and boundary conditions. Also the question of the particular business models for such capital demanding projects (high investment costs for the heating grid vs. low energy demand/sales) has been regarded.This closed project is a cooperative research activity and of the Fraunhofer Institute for Energy Economics and Energy System Technology (IEE) and Kassel University in a close cooperation with the City of Kassel and the local utility company Staedtische Werke Kassel AG. The project partners thank the German Ministry for Economics and Energy for the given support of this research work.