Turning a German coal mine into a pumped-storage plant, project has already cost EUR 2m

North Rhine-Westphalia has decided to invest a further nearly EUR 1 million in a project for an underground pumped-storage plant to be built within a former coal mine. The cost per kW of capacity for the project is expected to range between EUR 600-2,400.

A new pumped-storage plant could be built in Germany's most populous state, which has a strong focus on energy and industry. Specifically, the initial study concerns the Prosper Haniel mine near the town of Bottrop, which is due to close in 2018.

„North Rhine-Westphalia is a state where energy plays an important role, and we would like this to remain the case in the future. Large storage capacities will be part of the energy sector, and the vision of an underground pumped-storage plant may be an important factor in transforming our energy system.“

Johannes Remmel, North Rhine-Westphalia's Environment Minister

A 2012 study by the University of Duisburg-Essen and Ruhr University Bochum had already examined the possibility of converting coal mines in this region into pumped-storage plants. The study assessed the feasibility of projects of this type at two selected sites.

It evaluated both geological conditions and, for example, public acceptance of such a project. As a result, the Prosper Haniel mine mentioned above was recommended for a pumped-storage plant. The state had already contributed EUR 1.3 million to this initial study.

According to one of the study's authors, the high level of public acceptance of the project and the favourable geological conditions at the Prosper Haniel site are encouraging. In addition, the cost of installed capacity in the range of EUR 600-2,400/kW is comparable to that of conventional pumped-storage plants. However, construction of neither type is economically viable at current low electricity prices.

The state government has now pledged a further EUR 850,000 to the project. However, a number of research projects and studies must still be carried out before a final investment decision can be made.

Source of main image: commons.wikimedia.org, Prosper Haniel mine