DEPENDING on who you listen to, Deep Gas Winning (DGW) is either a game-changing technology with the potential to put coal back at the heart of Britain’s energy mix or a marketing ploy, masking a high-risk gamble with our natural environment.
Supporters say it will bring billions of pounds of investment and create thousands of jobs.
Critics link it to fracking and Underground Coal Gasification (UCG), warning of underground explosions and water contamination.
Part of the problem is that while UCG has been around since Sir William Ramsay first began experimenting at Hett Hills, near Tursdale, County Durham, in 1912, DGW is new and unknown.
Newcastle-based energy firm Five Quarter wants to drill boreholes going deep into the earth and then out into the North Sea, tapping into coal seams between 250m and 2km below the sea bed.
Down a first borehole, measuring about six inches across, they would send oxidants – air, oxygen or steam, triggering the coal’s partial oxidation.
Because the coal would not be combusted entirely, the gas formed – known as syngas – would maintain much of its original energy.
Additionally, due to pressures differences, trapped gases are released from area around the seam.
All these gases, a mixture of hydrogen, carbon monoxide, methane and carbon dioxide, would then be extracted via a second borehole back onto the shore, where they could be used to generate power, hydrogen, transport fuel or feed the petrochemical industry.
So, what are the problems?
Well, the reaction produces carbon dioxide (CO2).
Harry Bradbury, CEO and chairman of Five Quarter, says his firm is looking into “productisation” of CO2 – making use of it – and “sequestration” – storing it, possibly under the sea.
Campaign group Frack Off claim DGW is a “rather bizarre” term invented by Five Quarter to avoid using the phrase UCG, motivated by “growing public awareness” of the risks of that process – which they say include underground explosions and contamination of water supplies.
Dr Bradbury firmly dismisses the suggestion.
UCG has historically taken place on-shore and at relatively shallow levels, he says, whereas DGW would be off-shore and deep under the sea bed.
Frack Off claims work would “inevitably” move on-shore. Dr Bradbury denies this, saying in fact Five Quarter plans to move more of the process off-shore.
“At no point in time to the best of my knowledge has anyone from Frack Off ever contacted Five Quarter,” he says, “So it’s not surprising they have misconceptions.”
Dr Bradbury admits DGW is unknown and says he is unable to explain the process fully, due to an ongoing patents process.
However, he adds: “At the appropriate time, we would be perfectly happy to engage.
“Almost everyone involved at Five Quarter has spent the last two decades or more doing what they can in environmental management.
“We have a long and distinguished track record."