Copenhagen: September 24, 2024. The decarbonization of the heat supply is one of the major obstacles to a renewable energy system and, thus, a critical element for mitigating human-induced climate change. Geothermal energy can provide baseload heat resources if suitable subsurface conditions and heat extraction techniques are combined. The Christian-Albrechts-University of Kiel has been awarded a two-year research project by the EKSH (Energie & Klimaschutz Schleswig-Holstein). Stadtwerke Flensburg and the Danish company Green Therma contribute with co-financing.
The UPTES project (Untersuchung des Potentials tiefer Erdwärmesonden in Schleswig-Holstein), an acronym for the investigation of the geothermal potential of deep borehole heat exchangers in the state of Schleswig-Holstein, will investigate the geothermal energy potential of the widely distributed rock salt formations in the subsurface of Schleswig-Holstein for the direct supply to district heating systems. As a heat extraction technique, the closed-loop deep borehole heat exchangers, which involve drilling deep with a long horizontal section in the kilometer range, will be investigated as proposed by Green Therma.
Salt structures are usually considered a challenge or even prevent the use of conventional hydrothermal energy – the so-called doublet systems. Sebastian Bauer, Professor for Geosciences at the Christian-Albrechts-University of Kiel and project leader, says that the high thermal conductivity of rock salt in combination with comparably higher temperatures inside these salt structures may lead to sufficient energy output and temperature levels of these closed-loop systems. The innovative heat extraction technology and the geological conditions will be investigated in the UPTES project using numerical process modeling.
Kim Gunn Maver, Chief Geologist at Green Therma, states that his company has developed a new thermal isolation technique that minimizes thermal losses inside closed-loop systems. This new DualVac system can be used in vertical as well as horizontal boreholes and will be investigated in the model calculations. The expected project results will illustrate the use of geothermal energy from geological salt structures and how it can be integrated into a district heating energy supply, exemplified through a feasibility study of Flensburg as a type location for Schleswig-Holstein.
The project participants expect that this project can be pivotal in the development of geothermal energy use. It investigates a key energy source for district heating grids whose energy demand is expected to triple in Germany by 2045 due to the recently passed Building Energy Act.
