Company's plan for coal gasification in Swansea Bay
An energy company has revealed it wants to apply for planning permission and a permit to drill for coal and extract the gas from under Swansea Bay.
Clean Coal Ltd has five licences around the coast of Britain and is trying to locate reserves which are off shore and too deep to be mined traditionally.
It is thought up to 1bn tonnes of coal could lie beneath the surface.
But environmental group WWF Cymru says the focus should be on renewable energy not fossil fuels.
During the past two years the Coal Authority, on behalf of the Department of Energy and Climate Change, have - without much publicity - issued 18 underground coal gasification (UCG) licences.
Most are off the east coast of England and Scotland. The 77 sq km Swansea Bay licence is the only one in Welsh waters.
Shaun Lavis, Clean Coal Ltd's senior geoscientist, said: "We're expecting to find up to around a billion tonnes of coal actually in place under the whole of Swansea Bay in our licence area.
"What we hope to do is undertake an exploration programme to identify an area of around 30 to 50m tonnes or so of that coal that's suited for underground coal gasification."
He said UCG was more controlled than burning and did not produce as much heat and carbon dioxide.
He added: "Furthermore, what happens when you gasify the coal in the subsurface, is that a lot of the ash, or most of the ash and sulphur compounds will actually stay underground as well, so you don't have the issues with ash disposal and so forth that you might do with a conventional coal-fired power station."
The basic idea of UCG is that you find coal seams which are up to 500m (1,641 ft) underground - far too deep to mine, and probably too expensive and dangerous as well.
After drilling to find coal, a newer technology of horizontal drilling modified from the oil industry would then allow air and oxygen to be injected down to ignite the coal.
Oxygen combusts with the coal-producing synthesis gas - a combination of carbon dioxide, carbon monoxide, methane and hydrogen. The gas, or syngas, could then be piped to the surface via another borehole.
Swansea councillor Darren Price said members of the public would welcome potential job creation.
However, he added: "From a personal point of view, I want to see a lot more research and analysis in terms of the process and any potential negative impact environmentally."
He said it was still an "unknown process" and that the safety of local residents would be "paramount" when it came to the issue of storing gas
http://www.bbc.co.uk/news/uk-wales-16567883