· World's experts focus on trial in West Virginia
· Britain slow in developing projects, say critics
The 500ft cooling tower at the Mountaineer power station in New Haven, West Virginia, does not look much different from the scores that dot the British countryside. It might need a second look to notice that, in its shadow, there is a hole in the ground that goes two miles deep into the rock next to the Ohio river.
Next spring, the attention of scientists, engineers and policymakers from around the world will be focused on this power plant as engineers there try to crack one of the most urgent technological questions facing humans today: how to remove the carbon dioxide from the fossil fuels we burn and safely bury it where it cannot warm the planet.
Mountaineer is a modest project, aiming to trap just 100,000 tonnes of CO2 a year, the equivalent of a 20MW power station which could power 20,000 homes. But if it works, the plant's place in the history books, as the first successful trial of a complete carbon capture and storage (CCS) unit attached to a power station, will be assured.
CCS has the potential to make a big impact in reducing global carbon emissions - and the components of the technology all exist. At its best, CCS could prevent 90% of the CO2 emitted by power stations from getting into the atmosphere. Better still, it could be a vital tool for developing countries, such as China, where the government's economic growth and poverty reduction targets depend on building huge numbers of coal-fired power stations.The EU commissioner for energy, Andris Piebalgs, is unequivocal about the need for technology to bridge the gap until large-scale and more climate-friendly sources of energy become viable.
"CCS is absolutely necessary to reach climate change goals: there is no other way we could do it," he told a meeting of experts organised by the Norwegian environmental group Bellona.
The case for action on climate is compelling. Since the dawn of the industrial revolution, the world has burned the equivalent of 500bn tonnes of carbon, raising the atmospheric concentration of the gas from 280 parts per million to 387ppm today.
Last year the Intergovernmental Panel on Climate Change said that global emissions of greenhouse gases must peak by 2015 for the world to avoid dangerous climate change and have any chance of limiting the expected temperature rise to 2C. But the International Energy Agency predicts the world's use of power will increase by 50% by 2030, with 77% of that coming from fossil fuels.
Despite the urgency, governments and power companies are locked in a wrangle over who will pay. Individually, the technologies needed to capture, transport and bury CO2 have been developed and are used in oilfields and chemical plants. But no one has built an entire system attached to a power station. No one wants to be the first to pay the bills for the expensive set of demonstrations needed. Estimates of the average cost of retro-fitting Britain's aged power stations are around £1bn each, with pipes to transport the CO2 to suitable burial sites costing around £1m per mile.
"From an engineering point of view, we can do it," said John Loughhead, executive director of the UK Energy Research Centre. "We know how to do it but the cost frightens us. It comes down to how seriously the government takes reducing CO2 emissions." There are three broad approaches to CCS:
· removing the CO2 before combustion by treating the coal;
· scrubbing it from exhaust gases after combustion;
· or burning the fuel with extra oxygen to produce an almost pure CO2 exhaust.
The CCS process itself uses energy and it is estimated that between 10% and 40% of a power station's energy output could end up being used to run the scrubbing and transport systems.
Projects to demonstrate parts of the CCS chain are already under way. Norway's state oil company has been stripping CO2 out of the natural gas extracted from the Sleipner oil field in the North Sea for over 10 years. About 1m tonnes of CO2 is now injected into the sandstone aquifer under the seabed every year. BP runs a similar scheme at In Salah in Algeria while at Weyburn, Saskatchewan, 1m tonnes of CO2 a year is buried, piped in from a chemical plant 400 miles away in North Dakota.
The project in West Virginia, due to begin next year, will be the first of the pilot plants to put all the pieces of the CCS technology together, a testbed for a more ambitious plan to capture and store emissions from a coal-fired power station in Oklahoma which should begin operations early next decade, trapping and burying 1.5m tonnes of CO2 a year in a nearby oilfield.
Another project nearing the pilot phase is Swedish energy company Vattenfall's plan to build a €1bn (£800m) CCS demonstration plant in Brandenburg, Germany, testing the post-combustion and high oxygen burning methods. Further CCS projects have also been announced in Norway, Australia, the United States and Canada. The EU aims to have 12 demonstration plants running by 2015.
In the UK, however, critics argue that plans are too small-scale and too slow, despite government claims that the country is in a perfect place for CCS due to the easy access to suitable burial sites for CO2 in the North Sea.
Last year, the government announced a competition to fund the construction of a 400MW CCS demonstration project that would go on line in 2014. Officials will announce a shortlist of potential sites for the demonstration plant later this month, with a leading candidate for the award a proposed 1.6GW coal-fired power station at Kingsnorth in Kent.
There are no official details of cost but a spokesman for the Department for Business, Enterprise and Regulatory Reform indicated that funding could be hundreds of millions of pounds over 15 years.
Stuart Haszeldine, a geologist and CCS specialist at the University of Edinburgh, has said the government's "incoherence and timidity" in policy had caused a dramatic slowdown of CCS development in the UK. In 2007, there were 10 test projects in the pipeline, covering a range of CCS technologies, which together could have cut the UK's emissions by 20%. Half have been abandoned, mainly because they did not fit the criteria for the UK's competition.
A senior energy industry source said the government's decision to allow only post-combustion CCS technology to enter the competition had been a mistake. "The problem with CCS is that it's often seen as a sticking plaster that allows the coal industry to carry on as normal."
Even for those environmentalists who support CCS, the post-combustion approach reinforces all that is wrong with coal. Keith Allott, head of climate change at WWF, is concerned that it legitimises a "build now, retrofit later" mindset in the power industry. "We have up to eight new coal-fired power stations being considered in the UK - if those power stations are built without carbon capture and storage, then it will blow our chances of meeting reduction targets out of the water."
The energy minister, Malcom Wicks, said the choice of technology was intended to take into account the future energy generation plans of countries such as India and China. The UK government is part-funding a project with China that will use a pre-combustion method to trap CO2 in a plant near Tianjin, to help in addressing China's emissions, which will be more than 5bn tonnes a year by 2030.
Whichever technology wins out, the largest obstacle to implementation remains money. Commercial operators point out that electricity from power stations with expensive CCS kit attached could never compete on the open market. It is therefore unsurprising that companies are biding their time.
Gardiner Hill, CCS technology director at BP, said that the cost of building CCS into power plants should eventually be borne by a higher price for carbon in markets such as Europe's emissions trading scheme, meaning that it would be too expensive to build power stations without CCS. One potential source of money is to use cash raised by governments across Europe from the auction of permits to emit CO2 from the third phase of the ETS scheme in 2013.
In their CCS policy, released today, the Conservatives have promised to do exactly that to fund up to three full-scale demonstration plants. The Labour government has rejected any hypothecation of cash raised by the ETS auction.
The cost of inaction could also be high. Paal Frisvold, chair of environmental group Bellona Europa, pointed to an impact assessment report by the European commission. "It points out that, if we don't use CCS for reaching our climate goals, the price tag is going to be €40bn more expensive. Here are some good reasons to deal with the finances of it now."
Some environmentalists remain opposed to CCS. Gavin Edwards, of Greenpeace International, wants to see governments take a second look at renewable sources of energy and energy efficiency.
Jon Gibbins, an energy technologist at Imperial College London, sees CCS as an insurance policy.
Generating power from zero-carbon renewable sources is good, he said, but to genuinely protect the climate, you have to ensure that no one releases CO2 by burning coal or other fossil fuels for centuries ahead.
Gibbins said the UK had a moral leadership role on the global stage: "With CCS you're asking people to stuff money down a hole in the ground for the sake of the climate. If we're not prepared to do it, we can't ask anyone else to do it."
· This article was amended on Friday June 13 2008. An editing error meant that we said that fossil fuel burning has released 500m tonnes of CO2 since the dawn of the industrial revolution; in fact we had meant that the world had burned 500bn tonnes of carbon. This has been corrected.