Unconventional treasure: Shale gas is trapped deep inside rock formations.
Shale gas is a new and abundant source of natural gas, trapped in rock formations. Oil companies have known about it for decades but always dismissed it because it was too expensive and difficult to extract.
In the past few years new technologies that pump water underground to fracture the rock and free the gas have been perfected. The breakthrough has opened a new frontier for the energy industry and turned long-held assumptions about the world’s dwindling supplies on their head.
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