An energy firm is hoping to tap into the large natural gas reserves in former coalfields in south Wales.
British Gas' parent company, Centrica has been awarded two licence blocks in the Rhondda and Swansea valleys.
It holds a shared interest in a third application block near Caerphilly. If tests are successful drilling for coal bed methane could start in two years.
The technology used to drill into the coal seams has already been developed in the US and Australia.
The company hopes methane from depleted coal seams could eventually power homes and help reduce greenhouse gas emissions.
Centrica will commence pre-development studies later this year with a planning application expected in late 2009.
Subject to planning approvals, drilling could commence in 2010, with possible development by 2014.
Sam Laidlaw from Centrica said: "As part of our continued investment programme to secure long term energy supplies for our British Gas customers, emerging technologies such as coal bed methane offer an opportunity to maximise the UK's own energy resources."
Methane gas is the simplest of the fossil fuels we use, and makes up nearly 90% of the natural gas pumped into UK homes.
But it is also the second most important gas related to man-made climate change. Each molecule of methane causes about 25 times more warming than a molecule of carbon dioxide, though it survive for shorter times in the atmosphere before being broken down.
The company said capturing methane therefore could help reduce the environmental impact of background methane emissions produced by depleted coal fields.