Repurposing former underground coal mines by deploying emerging renewable energy and circular economy technologies

This presentation introduces the Research Fund for Coal and Steel (RFCS) GreenJOBS project, which approach is premised on leveraging five competitive advantages of underground coal mines to deploy emerging renewable energy and circular economy technologies:

(1) mine water for geothermal and green hydrogen. Geothermal energy is a renewable source that harnesses the heat from inside the earth, in our case, through the water that floods the mines. From a certain depth, the temperature of the subsoil is constant regardless of the season. Thus, a continuous and accessible energy source is available all year round. On the other hand, mine water represents an essential raw material for producing green hydrogen by electrolysis;

(2) connections to the grid that can be adapted to inject the electricity produced;

(3) large waste heap areas for installing photovoltaic/wind;

(4) deep shafts suitable for unconventional pumped hydro storage using dense fluids that has a smaller footprint and higher energy density than conventional pumped hydro energy systems; and

(5) fine coal waste for recycling into dense fluids employed by the unconventional pumped hydro storage; artificial substitutes for soils from coal waste and wastes from closely located agricultural industries, coal-fired power plants, and water plants; and rare earths from fine coal wastes.

The objective is to provide mining companies with two innovative business plans: a Virtual Power Plant where the energy produced will be sold to the grid or used to power electro-intensive industries or companies with constant energy consumption located close to mines, such as aluminium factories or green data centres; and a Green Hydrogen Plant where renewable hydrogen will be produced by electrolysis of mine water and electricity from renewable sources.