8 - Underground coal gasification

Underground coal gasification (UCG) is essentially the same well known chemical processes used in surface gasification that converts solid coal into a mixture of gases known as synthesis gas (or syngas). Rather than taking place in an expensive, purpose built reactor vessel, however, UCG takes place in coal seams while they are still buried deep underground. With a century of experimentation behind it, UCG is not a new technology. Relatively recent advancements in key enabling technologies have allowed UCG to develop into a safe, economic energy technology that is now at the stage of becoming commercialised in many countries around the world. This chapter contextualises the recent resurgence of interest in UCG, drawing on the lessons learnt from previous trials on aspects such as environmental risk management, and the impact of new technologies on the development of UCG.