Roger Harrabin reports on the principle, the practice, and the controversy of carbon capture
The UK government has given a massive boost to world ambitions to develop clean-coal technology. It announced a decision that will herald a new generation of coal-fired power stations in the UK - but all of them will have to have their CO2 emissions partially captured by cutting-edge technology.
Carbon capture and storage (CCS) has finally come of age. After years of skulking in the shadows of disbelief it is about to claim its place in the sun.
CCS has been championed by industries who stand to gain from it and by a few greens who reasoned it was the only technology which allowed China and India to burn the black stuff under their feet without sending emissions spiralling even higher.
It was distrusted by many mainstream environmentalists who saw it is a dangerous diversion from cleaner, renewable technologies.
Those fears have not completely evaporated - but it was significant to see green groups congratulating the Energy Secretary, Ed Miliband, for his leadership and vision, whilst harbouring residual doubts.
The CCS announcement was historic. Looking through the archive, I heard a TV reporter in 1969 intone that Drax in North Yorkshire might be the last coal power station to be built in the UK, as nuclear became the fuel of the future. And no new coal power station has been commissioned in Britain for more than 30 years.
Most energy experts now agree that coal has to play a part in securing energy diversity - especially with the intermittency of wind and uncertainty of nuclear new-build.
Building conventional coal stations would torch the UK's climate targets - so carbon capture was the only way out.
That solution was foreseen by few people in government five years ago. It has taken an impending crisis in energy and climate to focus minds on the need to fund the technology, probably with a direct levy of a few percent on bills, and - crucially - to insist that it is fitted.
Some important questions remain over the technology. I believe that it will prove feasible, if costly. The US has been injecting CO2 into rock to extract oil for decades.
I have visited three plants pioneering the technology - Polk in Florida where coal is "cooked" to produce gas and dust; Schwarze Pumpe in Germany where CO2 is captured in a pilot project by scrubbers in the chimney; and In Salah in the Sahara where BP is pumping its CO2 emissions into desert rocks.
They all appear to be working fine as components of the CCS process, and it is likely that they will work together in the UK for the whole process.
Some greens have been asking what happens if the CO2 leaks. But the CO2 will be locked into tiny cavities in the same sorts of porous rock that hold natural gas.
The pipes that lead to them will be capped with concrete. It is much safer than putting the CO2 into the air.
There are risks and uncertainties, though. Greenpeace points out that if CCS does go wrong, the UK will be left with a batch of coal-fired power plants that ruin all its climate targets.
The government is allowing leeway for the technology to be proven by insisting only that firms should install carbon capture on 20-25% of their emissions.
This is rational and fair, says Mr Miliband. The Opposition asked if there would be any limit to the emissions from the new plants until such time as the technology was deemed proven. They did not receive an answer.
There is more uncertainty on cost. When this project was first mentioned a few years ago the sum of half-a-billion pounds per plant for the extra equipment was mooted.
Now people are talking of between £1-2bn (of money raised from a levy on consumers).
Power firms managed to run rings round governments and gain billions of pounds in windfall profits from the EU Emissions Trading System.
In the unequal negotiation between teams of highly-paid industry consultants and hard-pressed civil servants, can we be confident that the consumers will not be ripped off?
The other little-mentioned factor is that CCS is by no means emissions-free. Each plant takes carbon to construct, and coal is carbon-heavy in its mining and transport.
It also takes extra energy to run the capture and storage process, meaning that substantially more coal has to be mined and shipped.
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