It's confusing as to how shale gas extraction offers the oil industry "a new green message", as it was suggested last week in an interview with Shell's outgoing chairman. Look a little closer at shale gas and it comes with all the type of problems we're coming to expect from extracting unconventional hydrocarbons. Now that we've got much of the easy stuff out of the ground, it's all getting a bit more complicated, leading to the use of new technologies to get to previously inaccessible reserves, and in so doing, creating new environmental problems we hadn't previously envisaged. Tar sands developments in Alberta, Canada, are the obvious case in point. With shale gas, the technology involved is called hydraulic fracturing – "fracking" for short. This involves blasting a solution of water, sand and various chemicals into the shale bed, two to three kilometres below ground, to fracture the rock and mobilise the gas. In order to get to the shale formation, operations have to drill through the aquifer, creating the potential for contamination; either from chemicals used in the process or those that are activated during fracking. In the US, where the industry is more developed, accusations of groundwater contamination abound. If ...
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