Fraunhofer Research Institution for Energy Infrastructures and Geotechnologies IEG
Fraunhofer Research Institution for Energy Infrastructures and Geotechnologies IEG
© Fraunhofer IEG/ Felix Jagert
View on the erected Bochum drilling site. The pipes (each 4 m long) are step by step brought down into the subsurface using a pipe handling excavator

© Fraunhofer IEG/ Felix Jagert

PUSH-IT

Piloting Underground Storage of Heat In geoThermal reservoirs

Within the European consortium PUSH-IT (Piloting Underground Storage of Heat In geoThermal reservoirs; funding code 101096566), the storage of surplus heat from existing heating and cooling networks in the local underground will be demonstrated at a total of six locations across Europe using various underground storage technologies (ATES, BTES, and MTES).

The overarching goal is to reduce environmental impacts, costs, and existing risks associated with the integration of underground storage systems within the framework of the research project, including through newly developed monitoring and quality control measures as well as improved drilling and installation procedures. The involvement of public and private companies, citizens, the analysis and perceptions regarding such technologies, and the development of new business models are key focuses.

The PUSH-IT consortium consists of heat suppliers, well construction companies, public planning offices, and academic partners. Through transdisciplinary collaboration across Europe, the individual demonstration sites will be developed.

The Fraunhofer IEG is part of the consortium and a demonstrator for the further development of underground storage systems in former mining structures (MTES). For this purpose, a demonstration site was established in collaboration between Ruhr University (RUB) and the Fraunhofer Institute for Energy Infrastructure and Geothermal Energy (IEG) at the site of the RUB's technical center.

The concept  integrates surplus waste heat into the existing supply network of RUB in the long term. To store this heat in the system, parts of the decommissioned Mansfeld mine will be hydraulically accessed through four vertical boreholes into the former mine building, located at a depth of approximately 120 meters directly beneath the RUB technical center, and examined and tested as a potential heat storage facility for the RUB network. The drilling operations were carried out by Fraunhofer IEG using the institute's own drilling rig.

Depending on the results of a hydraulic test operation following the drilling work, the boreholes may either serve as geothermal wells or as monitoring points for scientific investigations in the long term. Depending on the outcomes of the testing, the project may proceed to the next phase (integration of the facility into the existing supply network, possible takeover of the facility by RUB, and development of an operating concept).

The necessary technical and construction measures will be investigated and developed within the framework of the PUSH-IT project in collaboration between RUB and IEG.

Technisches Zentrums um 1943
© Quelle: Meier, Norbert; Lewer, Hans-Jürgen: Zeche Mansfeld. Wie Urbanus und Colonia zu Mansfeld wurden, 2012
Location of the current Technical Center around 1943: In the background, the former headframes of the Mansfeld shafts 5 and 6 can be seen (Source: Meier, Norbert; Lewer, Hans-Jürgen: Zeche Mansfeld. How Urbanus and Colonia became Mansfeld, 2012).
© Fraunhofer IEG/ Felix Jagert
View of the current Technical Center of RUB. Visible are the central heating power plant (consisting of 2 combined heat and power plants and 3 gas boilers) for the district heating supply of southern Bochum. The technical center also generates its own district cooling for the RUB campus, which, especially in the summer months, has immense waste heat potential, as the waste heat from the central chillers must be cooled down via the cooling towers visible on the right.
© Gernandt, Krenzlin 2023
Possible optimization concept for the heating and cooling network at RUB: Surplus waste heat from the central cooling generation could be partially stored in the underground former mine building at Mansfeld during the summer months and, if needed in the future, reintroduced to the existing supply channel of RUB, for example, through central large heat pumps (Gernandt, Krenzlin 2023).
PUSH-IT is funded by the European Union.
© Fraunhofer IEG