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GrEEN

From coal mining shaft to renewable energy source

It is more than 25 years since coal was mined in Aachen’s coal mining district. Today, on this former site of the energy industry, the ENERGETICON is raising public awareness of the shift from fossil to renewable energy – not just through the Energy Adventure Museum, but also by producing its own climate-friendly energy. This is the mission of the GrEEn project.

ENERGETICON’s location is particularly symbolic: situated on the north-western periphery of the former "Anna" amalgamated mine coalfield, in the middle of Aachen’s former coal mining district, the museum presents the thousands of people who visit it every year with a fascinating permanent exhibition on the energy transition as well as topically relevant meetings, workshops and events. Since September 2018, the museum has also been using the site in another way: its leaders have launched the “Grubenwasserenergie für das ENERGETICON“ (Mine water energy for the ENERGETICON” project) – GrEEN for short. As indicated by its name, the project uses mine water to generate energy. Since mining ended, the underground cavities have been filling up with mine- and ground water. The column of water in the 900-metre deep Eduard shaft, which is located in the middle of the ENERGETICON site, rises by approx. two centimetres per day and has an average water temperature of around 26 degrees Celsius.

Engine for progress:

  • Generating climate-friendly energy
  • The energy is used directly on site
  • Great potential for transfer to more than 100 suitable mine shafts in the Ruhr area alone

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Photo: Dominik Ketz

The ENERGETICON turns energy into a fascinating experience for young and old visitors alike through its interesting and informative exhibits. With the GrEEn project, the museum has also started generating its own climate-friendly energy.



Cost-effective and low-risk geothermal process

In order to use this heat, a geothermal probe was sunk down into the water column in the shaft to extract the heat right from the depths. This “single probe” contains pure water as the medium that absorbs the ambient heat from the mine water. A heat exchanger with a downstream heat pump then supplies this heat to the museum’s central heating system. This system can meet up to 70 per cent of the ENERGETICON’s heating needs. Compared to other geothermal processes, such as the doublet operation, this system has the advantage that the mine water does not have to be laboriously pumped up and then fed back in at another location. In addition, no costs or risks are incurred for exploiting the mine water since the shaft is already there.

Until test operations could be started in November 2018, a number of obstacles had to be overcome: since it was not possible to insert the geothermal probe into the shaft via the ventilation pipe as planned, it was necessary to drill 150 metres through the concrete seal. Further unforeseen challenges arose as a result of increased requirements due to the flammable mine gas and large disparities between the existing plans and the actual conditions in the shaft. In the end, it was possible to resolve all the problems by means of technology at an acceptable cost and to insert the single probe into the column of water in the shaft.

Blueprint for the Ruhr area

The project’s first results, expected in March 2019, are awaited with great anticipation, since, if they fulfil expectations, the project could serve as a blueprint for countless mining regions and shafts in North Rhine-Westphalia – thus transforming the former fossil fuel sources of the mining era into future-oriented renewable energy sources, which are not only ecologically but also economically viable. In the Ruhr area alone, it is conceivable that the project could be transferred to more than 100 suitable shafts.

Funding from the State of NRW

The project is funded by the Ministry for Economy, Innovation, Digitalisation and Energy of the State of North Rhine-Westphalia. Local energy company RWE-Innogy and the ENERGETICON are responsible for the co-financing.


Photo: ENERGETICON gGmbH

“An 860-metre-long geothermal probe (double U-tube probe) was freely suspended in the mine water-filled Eduard shaft, located on the ENERGETICON site, in order to use the geothermal heat of the mine water. The project was funded by the State of NRW and Innogy SE. By carrying out this project, we gained wide experience of working on a partially filled mine shaft and of the technical requirements in terms of materials and the method of installation for a geothermal probe that is suspended freely in the shaft. This experience will enable us to construct other facilities at former mining sites including those in the Ruhr area.”

Thomas König, Managing Director of ENERGETICON gGmbH




Partners and sponsors


Partners:
  • RWE Innogy
Sponsors:
  • Ministerium für Umwelt, Landwirtschaft, Natur- und Verbraucherschutz (MULNV)