As conventional fossil fuel sources dry up, the industry has been developing ways of extracting gas that is trapped inside the rock formations such as shale gas, coalbed methane and tight gas. Together, they are known as unconventional gas, because of the new techniques needed to access them.
The most controversial of these techniques is hydraulic fracturing, or “fracking”, made infamous by the 2010 film “Gaslands” which showed people in Pennsylvania setting their taps on fire, and linked this to rampant gas drilling in the Marcellus Shale.
Fracking involves drilling deep in the earth and pumping a mixture of water and toxic chemicals under high pressure into the bore hole to open up fractures and ease the flow of gas for extraction.
The energy industry promotes unconventional gas as a clean source of indigenous energy, and a crucial “bridging fuel”.
Opponents of shale point to the toxic cocktail of carcinogenic and gender-bending chemicals commonly found in fracking fluid, and an increasing number of studies showing that the carbon footprint of unconventional gas could be as much as that of coal. Even if local environmental impacts could be mitigated, burning the gas will make it all but impossible to meet global climate targets.
The less well-known coalbed methane is also making an unwelcome impact, particularly in Australia where the industry is facing increasing opposition. Unlike shale gas, coalbed methane doesn’t always involve fracking, however extracting this kind of gas has its own distinct risks as well as those very similar to shale.
Coalbed methane is extracted by de-pressurising the seams through drilling vertically and horizontally and pumping out water to release gas. But where seams are less permeable, or as gas flow starts to decline, wells can be fracked to increase productivity. In Australia up to 40 per cent of wells are fracked.
Communities living near gas fields link extractions activities to a host of health problems including headaches, persistent rashes, nausea, joint and muscle pain and spontaneous nosebleeds. Farmers are playing a key role in the widespread “Lock the Gate” coalition because of the impact de-pressuring has on their water supplies – in fact the industry has admitted that its impossible for them to extract the gas without affecting ground water levels.
Scotland has some shale reserves, but the most immediate threat is from coalbed methane. Australian gas company Dart Energy’s flagship coalbed methane project is at Airth, near Falkirk. Still at the testing stage, the project already has 16 wells drilled, and a live planning application proposes a further 22 wells. Full field development could see over a hundred wells in less than 300 square kms.
What makes the prospect of developments like these so alarming is that most of the unconventional gas resource in Scotland is located in the most heavily populated parts of Scotland – right across the central belt, with pockets in southern Scotland too.
In New South Wales the government recently introduced a ban on any coalbed methane extraction within 2km of residential areas. Communities living near coal and shale deposits may be wondering why they aren’t being afforded the same protection.
• Mary Church is campaigns co-ordinator of Friends of the Earth Scotland