Q&A: Will shale revolutionise gas?

Will hopes of abundant shale gas supplies prove nothing more than a pipe dream?

"If shale gas fails to deliver on current expectations, then in 10 years or so, gas supplies could face serious constraints."

So says Paul Stevens, a senior fellow at the international affairs think tank, Chatham House.

He's penned a report that raises serious doubts about whether shale gas will indeed deliver.

So what is shale gas, why is it such a big deal, and what will happen if it turns out to be one big wild goose chase?

What is shale gas?

So why all the excitement?

A core of shale rock from which gas is a natural by-product

Is that why the gas price has fallen so much?

Why has shale been such a big hit in the US?

So why can't it happen elsewhere?

Gazprom says that exploiting its gas shale deposits would be prohibitively expensive

What about here in Europe?

What happens if shale lives up to its billing?

Pennsylvania called a three-year moratorium on the Marcellus gas project over environmental concerns

What are the environmental problems?

So what happens if shale falls flat?

Uncertainty over shale is depressing investment in other gas facilities such as liquefied natural gas