UCG is ideally suited for complete extraction of both the solid and gaseous fuels from coal resources that are not destined for conventional mining to extract solid fuel.

Eskom has determined that UCG technology offers the following merits:

• UCG technology, in combination with a combined-cycle power station, significantly reduces the emissions footprint of a coal-fired power station.
• The overall resource utilisation efficiency is very high, especially when the gas is used for power generation in a combined-cycle power station. UCG as a mining technology also effectively extends South Africa’s coal reserves, by allowing extraction of coal previously disregarded as being unminable.
• The focus on “unminable” resources suggests minimal overlap with existing conventional mining houses, although conflict is possible with CBM developers.
• The broader geographic availability of coal suitable for UCG enables Eskom to position new coal generating plant far more strategically to support demand-side needs and stabilise the transmission network.
• The technology will increase Eskom operational flexibility and efficiency, by allowing the coal mine and power station to effectively integrate.
• The technology, on a large scale, offers the opportunity to reduce the cost of electricity from new coal-based power stations. It achieves this through an inherently simpler mining process, and a shorter resource-to-electricity production supply chain.
• It could be suitable for carbon capture.

The UCG technology is modular, and Eskom is already proving the first module. The modularity, availability, and relative simplicity of major plant components enable faster lead times than for conventional coal plant.

Eskom’s UCG demonstration plant in the foreground, with
Majuba power station in the background