Geothermal energy is currently used for district heating in Thisted and in Copenhagen. Energy is won by pumping up the warm water that is found in the pore space of the sandstones constituting the geothermal reservoirs. Other energy sources, such as incineration of domestic waste, can also be used for district heating. However, whereas our heat demand is highest in winter, the energy production is relatively constant. Therefore, we are looking at the possibility of storing the excess energy in summer in geothermal reservoirs. The plan is to use the additional energy to heat water and to inject this into the geothermal reservoir, in order to increase the temperature in the subsurface during the summer; during the winter, this additional energy can be pumped up and used for district heating.
The response of the reservoir rock to the injection of hot water is investigated by means of laboratory experiments; effects of temperature on permeability, geochemical reactions, and geomechanical properties are of interest. These experiments form the basis for subsequent geochemical and rock physical models that are used to plan energy storage.
To improve our understanding of the processes that occur we look to natural analogues. On a geological timescale as sediments get buried deeper in the Earth they are heated. Comparing the effect of this to the changes that are observed due to heating by hot water injection may provide valuable new insights.
Head of project: Prof. Ida Fabricius, ilfa@byg.dtu.dk
WP leader: Head of Laboratory GEUS, Claus Kjøller
WP leader: Prof. Klaus Mosegaard
Senior Researcher: Thomas Mejer Hansen
PhD: Esther Rosenbrand: esro@byg.dtu.dk
PhD student: Lisa Pasquinelli: lispa@imm.dtu.dk