Underground Coal Gasification Technology

• Underground Coal Gasification (UCG) is the gasification of coal in-situ, which is achieved by drilling boreholes into the coal and injecting water/air or water/oxygen mixtures.

• It is both an extraction process (like coal mining) and a conversion process (gasification) in one step.
• The product gas from UCG is a combustible syngas containing hydrogen, carbon monoxide and methane (H2, CO CH4). It can be used at surface for heating, power generation, hydrogen production, or the manufacturer of key liquid fuels such as diesel fuel or methanol.
• Interest in UCG as a secure and economic source of gas supply has increased over the past five years, most coal producing countries now have a comprehensive UCG programme comprising of feasibility studies, planning demonstrations and commercial scale projects
• In-seam and Directional Drilling technology, formulated for the oil and gas industry, has transform ed the UCG process, making it easier, more succesful and more commercially viable
• Commercial scale projects have started in Australia, China, South Africa, India.
• Large-scale operations (>1GW) were developed by the Soviets in the 1970's and at least one plant in Uzbekistan still operates today.
• Low natural gas prices in the 1990's eliminated much of the ongoing development in US, although in Europe, a substantial programme of development in deeper seams was maintained until the present day.
• Extensive trials in Europe, the US, Russia, Australia, have proven the technology on many occasions.
• UCG in combination with CCS (CO2 capture and storage) shows considerable promise as a low cost solution to carbon abatement. The composition of the syngas is particularly suited to CO2 capture and the high pressure from deep UCG will require smaller and less costly plant. The possibility of storing CO2 in nearby coal seams is a further option.
• Lower cost of plant and site development, no surface gaisifier required
• Safer, lower emissions, less surface disruption
• UCG offers a clean, safe, secure, indigenous energy supply