Coal at centre of fierce new climate battle

The debate over the impact of fossil fuels has been reignited by the imminent approval of a power plant at Kingsnorth, Kent. Could advances in technology provide ways of capturing dangerous emissions and make coal safer? Science Editor Robin McKie reports on a conflict of ideas
Robin McKie
The Observer, Sunday 15 February 2009

Engineers on the Sleipner East platform in the North Sea can lay claim to a unique environmental honour. Each year for the past decade they have pumped a million tonnes of carbon dioxide into an old gas field below their rig, a helpful contribution to the easing of global warming.
But there is more to the project, run by the Norwegian energy company StatoilHydro, than providing the world with some short-term climatic action. The engineers have also been studying the fate of that CO2 once it has reached its subterranean home. To their delight, the gas has stayed there, trapped in the pores of the field's sandstone rock.
"We have pumped millions of tonnes of carbon dioxide into underground fields," said project leader Tore Torp. "We see no signs of any escaping."
This lesson is crucial, say scientists. The world's longest-running carbon storage experiment has been a success and has shown that the technology is safe, effective and ready for implementation. Carbon dioxide from fossil fuel plants could soon be extracted before it reaches the atmosphere and be stored safely out of sight, a process known as carbon capture and storage (CCS).
"The idea is simple," said geologist Stuart Haszeldine, of Edinburgh University. "If you have CCS, power plant operators can still burn fossil fuels - without emitting carbon dioxide."
And not before time. According to energy experts, Britain now has no chance of meeting its climate change obligations and the planet has little prospect of tackling global warming without a means of stopping carbon emissions from fossil fuel plants. We can expand renewable power, build nuclear plants and improve energy conservation, but will remain at the mercy of power plants and factories that burn fossil fuels. The world is too dependent on carbon fuels to quit its addiction in a decade or two, it is argued. We need to deal with them directly and urgently, with prime emphasis on the most dangerous of all fossil fuels: coal.
According to Jim Hansen, the climate change champion and director of Nasa's Goddard Institute for Space Studies in New York, coal now rates as the greatest evil our planet faces. "Trains carrying coal to power plants are death trains," he says in an uncompromising opinion article in today's Observer. "Coal-fired plants are factories of death."
Many other scientists agree. Coal poses special environmental problems. It is dirty; burning it releases pollutants that cause acid rain; its combustion produces less heat than the burning of gas and oil, meaning that disproportionate amounts are needed to run power plants and factories. Yet in only a few weeks, the government is expected to approve construction of a massive new coal power plant at Kingsnorth in Kent.
Worst of all, however, is the simple fact that coal remains plentiful and cheap. "The world's oil and gas will probably run out in 50 years, but coal will last for hundreds of years," said Professor Dermot Roddy, of Newcastle University. "In Britain, with its two centuries of mining, we still have more than 100 years of coal supply. It will not run out overnight."
The fossilised remnants of 100 million-year-old plants, coal is still the world's major source of electricity, generating 41% of its power supply. Even in the United States, the most technologically advanced nation, almost half its electricity is generated this way. In rapidly developing nations such as India and China, new coal power plants are opened every month. For Hansen, the only solution is the introduction of a carbon tax across the globe. Companies would be taxed by national governments according to their levels of emissions. Any failing to set up such systems would have their exports taxed by the rest of the world. Fossil fuel plants, especially coal plants, would be priced out of existence.
But last week British energy experts warned that a system of carbon taxes had little chance of success, particularly in dealing with coal. "Coal is going to be available as a source of energy for at least another century and countries like China, India and Russia have particularly rich resources," said Mike Stephenson, head of science at the British Geological Survey. "It does not matter what we say in the west about they should do, they will always want to exploit their coal. If it is in the ground, people will always be tempted to use it. The only way round the problem is to make the use of coal safe and environmentally friendly."
In other words, only technology can save the day - in the form of CCS schemes. "The position is very simple," said energy expert Jon Gibbins, of Imperial College London. "The only way we can decarbonise our electricity production on the timescale needed to halt the worst effects of climate change is by setting up carbon capture and storage plants as matters of urgency." Nuclear and wind plants simply cannot be constructed in the time available.
This point was backed by the former cabinet minister Chris Smith in a lecture to the Royal Society for the Encouragement of Arts, Manufactures and Commerce this month. Carbon capture was, he said, the "perfect example of what can be done" and an opportunity to avoid repeating past mistakes.
"Twenty years ago, we lost out as Denmark and Germany shot ahead in developing wind-farm technology and now if we want to put big-scale offshore wind farms in place we have to buy most of the equipment from them," he said. "Let's not end up in the same position again."
Yet on its current timetable the government is destined to do just that. It is now assessing a number of small prototype projects, proposed by local authorities and power companies, that would be attached to power plants. A single winner will then be announced next year and given government support. Construction is expected to take three or four years and the plant would be then be run for several years. From the lessons learnt, the first major CCS plants would then be given the go-ahead, around 2020.
"That is simply too late," Stephenson said. "If we are to cut our carbon emissions by 20 per cent by that date, our only hope is through CCS. But if the government proceeds at its current pace, we will hardly be off the ground by then."
Only serious intervention will save the day. "We cannot expect power companies and local authorities to take all the risks," said Roddy. "We need some modest central commitment and investment for several full-scale projects in the next couple of years. Some plants will work better than others and we need to find out urgently which they are. And if, by some chance, CCS plants don't work, it is vital we know that as soon as possible.
"I am sure they will work, however. We know how to extract carbon dioxide on an industrial scale at petrochemical plants and we have learnt from projects like Sleipner how to store carbon dioxide underground. All we need to do is scale up proceedings. But we need to do that now, on a large-scale, at several sites, using different systems if we are to have a hope of getting CCS ready in time."
For Britain, the need to act swiftly over CCS is particularly acute. The nation possesses considerable North Sea oil industry expertise, a key advantage in developing expertise in CCS technology given that most projects are likely to be based near depleted, underwater oil and gas fields where leakage cannot affect towns or cities.
Thus the UK has a first-class opportunity to develop a technology with enormous industrial potential, not just as a means to hide CO2 from an overheating planet but as a technique for improving the recovery of oil. Pumping gas into a depleted field helps to push out its last reserves of oil. The technology is expensive, but combined with CCS could become increasingly viable.
Britain also has a moral obligation, say scientists such as Hansen. Per head of population, the UK has put more CO2 into the atmosphere than any other country. The nation that unleashed the industrial revolution has a lot to answer for, in other words. It is therefore clear that we should be taking a lead in the development of technologies that can fix the problem. "Certainly, we are in no position to tell China or India that they cannot burn coal," added Gibbins.
Exactly how CCS schemes would be funded is not yet clear. A carbon tax could still play a role, say experts - by making emissions costly enough to justify the price of building CCS plants.
Current estimates suggest it will cost at least £50 to bury a tonne of carbon dioxide. Given that a typical 800 megawatt power station will produce 5 million tonnes a year, it is clear this is not going to be a cheap technology. On the other hand, it is a technology that desperately needs validating, say energy experts. If it is not going to work, the world needs to know now before it places its faith in a dud saviour. On other hand, if it does work, as most experts predict, it needs to be implemented on a timetable that will give our warming world a chance to breathe as soon as possible.
Carbon controls
Three main types of carbon capture techniques have been developed:
Pre-combustion capture
Coal particles are mixed with steam, a reaction which produces hydrogen and carbon dioxide. The hydrogen is burned to drive turbines and the carbon dioxide is buried.
Post-combustion capture
Coal is burned normally and the carbon dioxide produced is then extracted and stored.
Oxy-fuel combustion
Coal is burned in pure oxygen, triggering high-temperature reactions which produce fewer polluting by-products.
Each system has its own advantages and disadvantages. Pre-combustion plants generate hydrogen, an extremely useful green fuel, but they can only be fitted to new plants. Post-combustion can be retro-fitted - a unit can be installed on to existing power plants. Oxy-fuel plants are expensive but generate little pollution. As a result, engineers argue that all three technologies need to be developed as speedily as possible and used where each is most appropriate.