| Title | Heat-Storage in Deep Hard Coal Mining Infrastructures |
|---|---|
| Authors | Rolf BRACKE, Gregor BUSSMANN |
| Year | 2015 |
| Conference | World Geothermal Congress |
| Keywords | Heat Storage, Hard Coal Mines, Integrated District Heating Systems |
| Abstract | The project aims to develop heat storing technologies in the subsurface infrastructure of hard coal mines. By end of 2018 the last productive deep hard coal mine in Germany - Prosper Haniel – in the Ruhr-Area will be closed down. That mine is the last one of more than hundred already closed coal mines in the industrial heart of Germany with more than 6 Mio inhabitants in a mélange of 50 cities. Although most of them are plugged at the surface many mines still have left major parts of their subsurface infrastructures – especially open parts of former galleries and working faces. Due to the large dimensions of tens of km2 per mine, depths of max. 1.500m at rock temperatures up to 50°C the mines have the potential to become an enormous geothermal reservoir for seasonal heat storage. Wasted heat from fossil fired power plants, garbage incineration and industrial production processes in the Ruhr Area may be stored during the summer season together with non-used heat from solarthermal plants on brownfield sites in cities. During winter time this heat will be used directly in single construction complexes and in city areas that are not connected to the existing district heating grids. Numerical simulations and technical investigations focus on the prototype Hard Coal Mine Prosper Haniel in the City of Bottrop; with: • Identification and testing of new, cost-effective materials, insulators and construction principles in the subsurface; • Enhancement of storage density with innovative materials and heat transfer media; • Optimization of seasonal storage concepts for large building complexes and new urban development areas; • Placement of closed-loop hydraulic circulation systems in accessible areas of the mine; • Connection to the existing district heating grids; • Enhancement of the energy efficiency of electricity-driven combined heat-and-power production systems and of heat extraction processes in district heating systems. For the conceptual modelling and for the dimensioning of an appropriate heat-storage in the subsurface infrastructure of the mine most relevant geotechnical, hydrogeological and geophysical parameters for the Prosper Haniel Hard Coal Mine are investigated. The total mining area is 165 km2 and the subsurface galleries have a total length of 151 km at a maximum depth of more than 1200 m with more than 40°C. There are 3 vertical shafts leading into the mine. Assuming that only 1% of this area may be used for heat-storage and a thickness of the storing geological formation of 100m the total storage capacity is ca. 100 GWh/K. |