As per estimated data the world’s recoverable coal reserve will last about
150 to 200 years at the current production rate. Mining is the typical method
of extracting coal, with these traditional methods only 15% to 20% of the total
coal reserve is recoverable. If unrecoverable coal is considered as resource,
the lifetime of coal will be extended by perhaps a couple hundred years. Mining
involves a lot of man power, high cost of machinery, changes in landscape and
post extraction transportation.
A new type of coal extraction
method, known as Underground Coal Gasification (UCG) addresses most of the
problems of coal mining and is being implemented globally. UCG is a
gasification process applied to in situ
coal seams which are often located deep below the earth surface and are
uneconomic to be extracted by traditional mining methods. UCG is very similar
to surface gasification and produces syngas through same chemical reaction
which take place in surface gasifiers. The produced syngas can be used as a
fuel to generate electricity or steam, as a basic chemical building block for a
large number of uses in the petrochemical and refining industries, or for the
production of hydrogen. UCG when combined with carbon capture and storage
techniques proves to be a clean energy source. When linked with modern combined
cycle turbines, gasification is one of the most efficient, environmentally
effective means of producing electricity from solid or liquid feed stocks. This paper is an attempt to present that UCG
is an effective, economical, and viable solution for conversion of
unrecoverable coal resources to useful reserves hence lead to
future sustainability.