Until recently, there were concerns the world would run out of oil and gas - but the development of hydraulic fracking has diminished those fears.

The US is producing more oil than it imports and this is seriously denting oil-producing countries' export earnings.

For many years, the Opec cartel was able to manipulate prices through their grip on supply - however, many forecasts now suggest that in Europe the price of Brent crude may soon fall below $100 a barrel.

Nigel Cassidy reports.