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Pioneering effort aims to tackle global warming

By Fiona Harvey, Financial Times

In the north of Scotland, preparations are under way for a power station that will test the limits of science in attempting to tackle global warming.

The plant, planned by BP and Scottish and Southern Energy, the UK energy companies, would convert natural gas into carbon dioxide and hydrogen. Electricity can be generated from the hydrogen using a new technique, while the carbon dioxide can be stored under the North Sea in the Miller oilfield. If successful, the plant could produce more carbon-free electricity than all of the UK's existing wind farms.

It would be one of the first of a pioneering range of installations that remove carbon dioxide that would otherwise be released into the atmosphere and place it in storage deep underground where it should stay for millennia.

Carbon capture and storage sometimes known as carbon sequestration is not a new idea. Since the mid-1990s, Statoil, the Norwegian oil company, has been taking carbon dioxide extracted from gas production in its Sleipner West field in the North Sea and storing it 1 km underground. BP has been operating an experimental plant in Algeria since last year. Other companies have also begun to investigate the possibilities of the technology.

But the technique has been moved from academic obscurity to the forefront of the political debate over climate change by the enthusiastic support given by President George W. Bush and other political leaders.

Fossil fuels

The Bush administration sees the capture and storage of carbon dioxide and other greenhouse gases as essential to tackling climate change. Its most fervent supporters posit the technology as a relatively comfortable way of continuing the world's reliance on fossil fuels while tackling climate change, without the wholesale disruption that would be involved in switching to alternative sources of energy.

The trouble with fossil fuels is that burning them releases carbon dioxide. Colourless, odourless and in other ways innocuous, carbon dioxide belongs to the group of so-called "greenhouse gases". These trap infra red radiation on earth that would otherwise dissipate into space and this gives rise to climate change.

The earth's climate is a complex system that constantly changes naturally but most scientists now agree that the release into the atmosphere of greenhouse gases such as carbon dioxide and methane is contributing to a global temperature rise with unpredictable effects.

According to scientific estimates, concentrations of carbon dioxide in the atmosphere have increased from 280 parts per million in the pre-industrial mid-eighteenth century to about 375 parts per million today. That is likely to rise much further. As developing nations such as China, India and Brazil seek to catch up with their developed counterparts, they burn fossil fuels at an unprecedented rate.

What the thirst for energy in China will do to the climate is now a matter of deep concern for scientists and political leaders.

Furthermore, once produced, carbon dioxide remains in the atmosphere for as long as a century, so that the concentrations we see now would not diminish for many decades even if we reduced our fossil fuel consumption dramatically.

For these reasons, carbon capture and storage looks increasingly attractive. The idea sounds simple: the carbon dioxide is captured as it is produced, transformed to a liquid or "supercritical" state between a liquid and a gas, and then pumped into old oilfields where it can have the effect of displacing any remaining oil, making it easier to remove by drilling.

But some environmental groups remain cautious on the prospects for carbon capture. Robert Napier, chief executive of the World Wildlife Fund, the environmental charity, says: "The science is not really there yet, in our view. It needs more re-search." There are some important questions that must be answered before the technology can take its place as a weapon against climate change.

First, is it safe? Pumping gas deep underground may seem a risky thing to do. But it should be just as stable when pumped deeply into old oil and gas reservoirs as the fossil fuels that lay there undisturbed for millions of years, says Sam Holloway, a geologist at the UK's Energy Research Centre. "If you look at the reservoir rocks, like sandstone where oil is stored, the spaces [when oil is extracted] are filled with saline water. You could displace the water with carbon dioxide. Under the pressures and temperatures that pertain in these reservoirs it would be stable," he explains.

Low-level leakage of carbon dioxide injected into these reservoirs could result in the acidification of the surrounding sea. But Holloway says the indications from projects such as the one undertaken by Statoil show leakage is unlikely.

Another problem is how to capture the carbon in the first place. This can be done using chemicals called amines that absorb the carbon dioxide at one stage of the process and then give it up again at another stage. But it is easiest to capture the carbon dioxide at the stage of extracting oil or gas, where carbon dioxide often forms a proportion of the fossil fuel in its natural state.

Usually, this carbon dioxide is simply vented into the air. It is more difficult - but still possible to remove carbon dioxide from other large sources of emissions, such as power stations. Smaller sources of carbon dioxide factories, homes and vehicles will probably never be suitable candidates for this technique.

The legality of pumping carbon dioxide widely into some undersea areas has also yet to be tested, notes Holloway.

Costly

Finally, is it economical? As carbon capture and storage techniques are still in their infancy, the economics of the technology are still unclear. It will certainly represent a cost to businesses: releasing carbon dioxide into the atmosphere has been free throughout history, and only recently have some governments taken action to put a price on the gas.

Extra revenues from using carbon dioxide to displace oil in depleted fields are likely to be outweighed by the fact that similar results could be obtained by pumping in sea water.

Lord Browne, chief executive of BP, told the Financial Times that subsidies might be needed to make the research, development and implementation of the technique attractive to oil companies. He said BP was likely to make "only a very moderate return" from its research, and the technology "needs a government subsidy in order to be able to compete just as wind and other renewable energy sources receive a subsidy".

But his call has led to criticism from parliamentarians in the UK. The UK government has agreed to devote £25 million (Dh165.15 million) to research into carbon storage in the North Sea. Awarding more public funds to oil companies that are making huge profits from the high price of crude is likely to be politically unpopular at a time when consumers are having to pay more for their petrol and electricity.

Even if the economics work out, others question whether carbon capture and storage should really be a focus, when more effective ways of reducing our need to spew carbon dioxide into the atmosphere can easily be found. Michael Dorsey, a professor of environmental studies at Dartmouth College in the US, says: "Dollar for dollar, you get more reduction of carbon dioxide from efficiency measures than from using nuclear power, and I think [the same will hold true of] carbon capture and storage."

Financial Times