Although gas is cheap and plentiful in the USA, opinions vary as to whether it will be affordable or expensive on the global market.

BBC: Gas-fired power stations to be encouraged by government

But before a test well has been drilled, it is near-impossible to be sure whether the geological idiosyncrasies that excite oilmen will yield either oil or gas (or sometimes both, and often nothing).

ECONOMIST: An unconventional bonanza | The