Scotland plugs into Forth coal

• The Firth of Forth has huge coal reserves under it, which Thornton New Energy wants to exploit. Photograph: Liam Rudden

Fife-based Thornton New Energy has gone into partnership with an Australian company to extract energy from coal seams lying deep under the estuary inaccessible to conventional mining techniques.

The technique – underground coal gasification (UCG) – involves pumping oxygen and steam down a borehole into the seam, where heating under controlled conditions extracts gases from the coal. The gases are then pumped ashore to be used to generate electricity.

Talks will take place this week on a site for the conversion plant on the south coast of Fife, with commercial production expected to start within three years. Although the initial power plant will be small – 10 megawatts, enough to power 5,000 homes – it will be replaced by a 120MW facility.

Last week, the company said, it gained backing in principle for up to 25 million to turn the project into reality. Test boreholes are to be sited on an industrial park in Methil to ensure the technology works before the operation moves to bigger-scale rigs offshore.

Further expansion could eventually generate more than a gigawatt. Spokesman Alan Borrowman said the company had spent four years getting the project to this stage.

He said: "This is the best coal in Europe in terms of quality and where it lies. There is a huge amount of coal down there which you can't get at by opencasting or deep mining.

"UCG is the best way to get at it and we know the technology works, it is already in use in other countries. There is enough coal under the Firth of Forth to provide the energy needs of Scotland for the next 150 years."

The Fife coalfield was once one of the powerhouses of the UK but stocks that could be safely reached from the land dwindled towards the end of the last century.

However, massive untouched seams lie under the shallow estuary, about 500m to 2km down. The government licences granted to Thornton and its partner cover a seabed area of almost 100 square miles east of a line drawn across the mouth of the firth from Edinburgh to Kirkcaldy.

"There are at least 20 seams stacked vertically on top of each other after many centuries of coal formation," Borrowman said. "It's a huge untapped resource."

Traditional coalmining – whether deep-mined or opencast – has attracted opposition from environmental groups as coal is a non-replaceable fossil fuel which, when burned, produces climate-changing gases such as carbon dioxide (CO2).

UCG has less of a direct environmental and social impact than conventional methods as well as removing the need to send people underground.

Both the extraction and burning the methane to generate energy produce CO2 but if a way is found to capture and store the gas, the technology might gain the acceptance of environmental groups.

The technology involves injecting water as steam and oxygen under pressure into a coal seam via a borehole. The coal, water and oxygen react under ignition from a second borehole to produce, among other gases, hydrogen, carbon monoxide, methane and CO2. These escape via another borehole, and contaminants such as tars and phenols are removed.

The purified gases can then be used to produce electricity or fuels.

This approach, if the CO2 is captured and stored, results in lower emissions of air pollutants and UCG plants would have lower visual, noise and dust impacts than opencast or deep coal mines. The technology would also avoid generating spoil heaps on the surface.

Thornton, and its partner Riverside Energy, is currently in discussions with experts on carbon capture and storage.

Doug Goodall, the managing director of Riverside, said, "Our experience in energy-related mining and exploration lead us to identify the Firth of Forth as one of Europe's premier deposits for UCG.

"We can expect extremely high recovery factors without many of the cost factors that are normally associated with deep mining.

"UCG is a method of realising the vast potential of this energy reserve."

UCG is also expected to avoid the environmental protests against power stations that use conventionally-mined coal from overseas.

This week, Ayrshire Power will announce it has submitted plans to build a new 3 billion coal-fired station at Hunterston. Pressure group WWF Scotland said it would be at the forefront of a campaign of opposition.

But Friends of the Earth Scotland said it backed the idea of a trial of the UCG technique. "The environmental impact is far less than either conventional mining or importing coal so in contrast to what is being planned for Hunterston there are significant potential advantages," said chief executive Duncan McLaren.

Thornton is the first company awarded a licence for UCG in the UK. The Coal Authority has also now granted more exploration licences for Northumberland, west Cumbria, Liverpool Bay, Solway Firth, Swansea Bay, Humberside, Sunderland and Norfolk.

A Fife Council spokesman said: "This is an exciting new idea and we are keen to work with the company as it develops this pioneering new clean-energy technology."