"The common wisdom was that unconventional gas was too difficult, too expensive and too demanding," he said, according to Petroleum Economist. "This has changed. If we ever doubted that gas was the fuel of the future – in many ways there's the answer."

The breakthrough has been to combine 3-D seismic imaging with new technologies to free "tight gas" by smashing rocks, known as hydro-fracturing or "fracking" in the trade.

The US is leading the charge. Operations in Pennsylvania and Texas have already been sufficient to cut US imports of liquefied natural gas (LGN) from Trinidad and Qatar to almost nil, with knock-on effects for the global gas market – and crude oil. It is one reason why spot prices for some LNG deliveries have dropped to 50pc of pipeline contracts.

We may soon be looking at an era when gas, wind and solar power, combined with a smarter grid and a switch to electric cars returns the country to near energy self-sufficiency.

The major problem environmentalist have witht his process is that it uses millions of gallons of water mixed with sand, hydrochloric acid and toxic chemicals which are blasted at rock. This is supposed to happen below the water basins but accidents have been common. Pennsylvania's eco-police have shut down a Cabot Oil & Gas operation after 8,000 gallons of chemicals spilled into a stream.

Plus, it isn’t exactly green. Natural gas has much lower CO2 emissions than coal, even from shale – which is why the Sierra Club is backing it as the lesser of evils against "clean coal" (not yet a reality). The US Federal Energy Regulatory Commission said America may not need any new coal or nuclear plants "ever" again.