Underground Coal Gasification

Among the proposed approaches to reducing carbon emissions associated with coal is underground coal gasification, or UCG. The process was promoted by David W. Gamp of the Lawrence Livermore National Laboratory during a presentation in Fargo last week at The Future of Coal and Biomass in a Carbon-Constrained World: Technology and Policy Opportunities, a conference sponsored by the Great Plains Institute.

The UCG process is achieved by creating a controlled underground fire in a coal seam to produce gases that are then brought to the surface. The product gas can be burned to generate electricity or to make liquid fuel products and fertilizers.

David Gamp's Fargo presentation highlighted several advantages of UCG. These include less surface impact and more efficient capture of carbon emissions when compared to the traditional gasification process. Gamp estimated that carbon capture costs with an UCG project could be as much as 50% less that methods used by surface gasification plants. He also highlighted the cost advantages of eliminating the mining, washing, transporting of coal and the construction of surface facilities required by traditional coal gasification.

An additional advantage that was emphasized is that UCG can use coal that is not economical to mine (deep coal or coal with high ash or high moisture content), which potentially could increase total useable coal reserves by several fold.

There are important factors that limit where a UCG project can be located, according to Gamp. These include the depth of the water table, the depth and thickness of the coal seam, the characteristics of the surrounding geology and the current land uses in the area.

In addition to the Lawrence Livermore website, further information about UCG is available at the British UCG Partnership website and the UND Energy and Environmental Reseach Center website.