16 January 2007 - The fight to cut greenhouse gases may be too reliant on unproven carbon capture technology, experts warned yesterday.

Sir Nicholas Stern advocated capturing carbon from coal power stations in his government-commissioned review of the economics of climate change, published in October. Yesterday, he highlighted its importance at the Royal Society of Arts in London, saying carbon capture and storage was likely to be a key component of any strategy for cutting greenhouse gases.

The European Commission, setting out its energy and climate change plans last week, also heavily emphasised the technology as a method of reducing greenhouse gas emissions. Carbon capture requires power stations, usually coal-fired plant as they produce most carbon dioxide, to capture the gas as it is produced and then compress and bury it in underground storage sites.

But David Porter, chief executive of the UK's Association of Electricity Producers, warned that the European Union might be over-optimistic: "They did seem to set a lot of store by carbon capture and storage.

"We are keen to see it exploited but it looks as though they expect it to become viable more quickly than is likely to be the case. It's not yet proven.

"If it can be made viable we will be delighted but we're not there yet."

Jon Gibbins, lecturer in energy technology at Imperial College, said: "You're pushing money down a hole in the ground [by burying carbon dioxide]. That's quite expensive."

Charlie Kronick, senior policy adviser at Greenpeace, also warned that the technology was at least ten years off, while action could be taken now to reduce emissions, for instance through energy efficiency and renewables.

Carbon capture and storage is seen as one of the most important ways of reducing emissions, because the world is likely to continue to use large quantities of fossil fuels for decades, even as more and more electricity is generated from nuclear fission and renewable sources such as the wind and the sun.

The world's consumption of coal is rising as China and India build hundreds of new power plants to cope with soaring energy demand. However, some developed countries are also increasing their reliance on coal as concerns rise over energy security and the doubtful supply of oil.

For instance, in the UK, the Department of Trade and Industry said this month that electricity companies used 23 per cent more coal and 12 per cent less gas, which releases lower levels of carbon dioxide, in the third quarter of 2006 than they did in the same period a year earlier.