Germany explores underground caverns as seasonal heat storage sites
Handelsblatt
Germany is stepping up its research on geothermal energy storage, a way of storing heat energy between seasons using water, business daily Handelsblatt reported. Research is currently underway in former coal mines in Germany's Ruhr valley, for example, to explore the potential of storing heat that can later be used to warm homes, as well as buildings in the public and private sector.
"There are already thousands of Geotes systems [geothermal energy storage systems] in the Netherlands and Scandinavia. Now more and more research is also being carried out in Germany," said Kathrin Menberg, researcher at the Karlsruhe Institute of Technology (KIT) which is exploring projects. The research institute Fraunhofer IEG is also working on various projects and researching the safety and economics of storing heat in old mines.
"Geotes promise the almost universal availability of cheap and practically inexhaustible storage capacities," said Peter Ruschhaupt from the think tank Future Cleantech Architects (FCA). The determining factor for whether the process is economically viable is the cost of drilling, he told Handeslblatt. Once the caverns are ready, the technology can be very cost effective, as heat can be stored for an entire season.
Geothermal energy storage works by heating water and channelling it back underground, with the surrounding rock retaining the heat for months in suitable locations. The warm water can then be pumped back to the surface and used for district heating, for example.
Germany is taking steps to decarbonise its heating sector by phasing out fossil-run boilers and requiring cities to draw up municipal heat plans by mid-2028 latest. Geothermal energy could cover 40 percent of the country's heating needs, according to the German geothermal association. The building sector is set to miss its 2030 climate targets as it continues to rely on fossil fuel boilers and energy-saving renovations proceed at a very slow pace of less than one percent of the building stock per year.
