With declining mineable coal reserves and increasing global energy demand, underground coal gasification (UCG) is a resurging technology that provides a solution to these challenges.
Nonprofit trust the Fossil Fuel Foundation (FFF) states that there is a need to develop environment-friendly and cost-effective technologies such as UCG to ensure that this energy supply can be exploited to its full potential.
The foundation adds that this is a viable alternative to coal-generated electricity, which is South Africa’s indigenous energy resource base.
State-owned power entity Eskom has been the main contributor to UCG research in South Africa, which is based on the Majuba coalfields, in Mpumalanga.
During the research, gas was successfully obtained and fuelled into the Majuba power station.
“They are now poised to develop a larger scale demonstration UCG project, which may produce the world’s first commercial UCG operator supplying electricity for baseload power supply,” states the foundation.
A potential target area for establishing a UCG project such as this has been identified in Theunissen, in the Free State, which contains a 300 km2 coalfield at an inferred level of reserves consisting of 1-billion tons, according to the FFF.
“Fundamental coal science, gasification understanding and expertise will form the foundation of a UCG development programme focusing on research and development of coal science.”
FFF director Professor Rosemary Falcon adds that this technology could transform the face of coal mining and electricity production in South Africa, should government approve.
The UCG process enables efficient production of energy and chemicals from coal, without the need for conventional mining operations, stockpiling, reclaiming and transportation.
“Another advantage is that no coal is brought to the surface and not only are environmental impacts greatly reduced, but there is no risk of underground casualties,” the FFF reports.
UCG takes place in undisturbed and often unmineable coal seams and is the gasification of coal on-site by remotely operating a series of boreholes. Air or a combination of oxygen and/or steam is injected into the gasification panel within the coal seam.
The coal is then heated and controlled; reactions convert solid coal into product gas, known as syngas, which is extracted at the surface. This can be used as fuel for heating, power generation, hydrogen production, or the manufacturing of key liquid fuels such as diesel fuel or methanol.