“Frack away, there’s no reason not to.”
Graham Lawton comments in New Scientist:
Two of the main objections to “fracking” for shale gas have been blown out of proportion, according to British geologists.
Hydraulic fracturing, or fracking, involves pumping water, sand and chemicals into methane-rich shale deposits around 2 kilometres underground to liberate natural gas. It has been accused of contaminating drinking water with methane and chemicals, and causing minor earthquakes.
“We think the risk is pretty low,” said Mike Stephenson, head of energy science at the British Geological Survey at a press briefing in London on Tuesday.
The idea that fracked methane leaks into drinking water was popularised by the documentary film Gasland, in which a resident of Pennsylvania sets his tap water alight (see photo). On Tuesday, Stephenson said he could not comment on this specific case, but that such contamination is unlikely.
Peer-reviewed research on methane contamination is scarce but what little there is suggests fracking is not to blame.
Underground deposits of drinking water often contain methane anyway, and there is little reason to believe that gas liberated by fracking 2 to 3 kilometres beneath the surface could work its way up into drinking water deposits that are usually less than 50 metres deep. The same is true for fracking chemicals.
Fracking does cause minor earthquakes, but these “fraques” are comparable in size to the frequent minor quakes caused by coal mining. What’s more, they originate much deeper in the crust so have all but dissipated by the time they reach the surface.
A crack in a road in Blackpool, UK, that supposedly appeared after a fraque last November had actually been there for years, Stephenson said.