What Is Underground Coal Gasification?

Underground Coal Gasification (UCG) has featured in the news over the last week after the Scottish Government announced a temporary ban on the practice. Here, we explain what it is, and how it affects Fife.

What is UCG?

UCG is a process that converts coal into product gases like methane, hydrogen, carbon monoxide and carbon dioxide. First, wells are drilled into the ground from the surface. Air and oxygen are injected into unmined coal seams. This coal cannot be mined because the seams are too deep, thin or fractured. Gases are released, then brought to the surface through the wells. They can then be combusted to produce electricity. It is an alternative to coal mining.

Is it like fracking?

Fracking is similar, in that it involves drilling into coal seams to extract gas. The main difference is that, with UCG, air and oxygen are injected into the coal. Fracking involves a liquid, called "frac fluid" being pumped into coal. UCG converts coal into gas (via heat) where as fracking releases trapped gas by ‘fracturing’ the coal bed. Fracking is also subject to a Scottish Government moratorium.

Is UCG happening in Fife?

UK based Cluff Natural Resources were planning to extract gas using UCG in the Firth of Forth, near Kincardine. Those plans were put on hold in August 2015 due to "political uncertainty". At the time, Cluff said: "Preparatory work including site selection studies, modelling and design work are however well underway". In October 2015, the Scottish Government announced a moritorium (a temporary ban) on UGC in Scotland, to allow for further research. However, the ban still allows for test drilling to take place, according to anti-fracking campaigners.

Why are people worried?

As with fracking there are concerns over the environmental impact of drilling underground, particularly around contamination of groundwater (which provides drinking water). Anti-fracking campaigners Frack Off say the process produces "a witches brew of toxic and carcinogenic coal tars". There are also worries over carbon emissions. According to Cluff Natural Resources, "there are negligible fugitive emissions associated with UCG projects".

What happens next?

For now, UCG remains banned under the Scottish Government moratorium. A timetable for a research and consultation process into the impacts of UCG has also been published, concluding in Spring 2017.

Sources:

1. http://www.clarke-energy.com/gas-type/coal-gas/
2. http://fmp-tv.co.uk/2015/06/01/fracking-ucg-underground-coal-gasification/
3. http://frack-off.org.uk/extreme-energies/underground-coal-gasification/
4. http://www.cluffnaturalresources.com/aboutducg.aspx