China plans to begin large-scale production of its shale gas deposits after 2015 when a solid foundation for developing the unconventional fuel is laid then, according to the nation's energy chief yesterday.

This means the government is not in a rush to extricate the fuel, tightly trapped in rock formations, as it has first to study exploration expertise by cooperating with foreign partners in projects both home and abroad.

China claims to possess the world's largest shale gas reserves, doubling those of the US where advances in production techniques have ended America's dependence on gas imports. The Ministry of Land and Resources, in its first official estimate of shale gas reserves, early this month said China holds 25.08 trillion cubic meters of technically recoverable deposits, enough in theory to meet China's needs for two centuries based on current consumption.

Liu Tienan, head of the National Energy Administration, under the National Development and Reform Commission, said in Beijing that a dedicated plan on shale gas has been drafted and will be released shortly.

The plan includes a target of 6.5 billion cubic meters of annual shale output by 2015, and a more ambitious 80 billion cubic meters by 2020. But Neil Beveridge, analyst at Sanford C. Bernstein & Co, has questioned the ability to meet the 2020 goal because more reforms are needed to spur investment and technology to commercialize shale gas.