Carbon capture under fire
A new research paper from American academics is threatening to blow a hole in growing political support for carbon capture and storage (CCS) as a weapon in the fight against global warming.
The document, from Houston University, claims that governments wanting to use CCS have overestimated its value and says it would take a reservoir the size of a small US state to hold the CO2 produced by one power station.
Previous modelling has hugely underestimated the space needed to store CO2 because it was based on the ‘totally erroneous” premise that the pressure feeding the carbon into the rock structures would be constant, argues Michael Economides, professor of chemical engineering at Houston University, and his co-author, Christene
Ehlig-Economides, professor of energy engineering at Texas A&M University.
‘It is like putting a bicycle pump up against a wall. It would be hard to inject CO2 into a closed system without eventually producing so much pressure that it fractured the rock and allowed the carbon to migrate to other zones and possibly escape to the surface,” Economides said.
The paper concludes that CCS ‘is not a practical means to provide any substantive reduction in CO2 emissions, although it has been repeatedly presented as such by others.” The report has come at a time when governments worldwide have started to fasttrack a series of CCS prototype schemes as a way of removing carbon from the atmosphere and helping with climate change.
On April 8 in the UK the Energy Act 2010 became law. It plans to raise a levy on power users to establish four CCS projects in Britain. Ministers see this as a potentially planet-friendly way of building new coal-fired power stations.
The Carbon Capture and Storage Association (CCSA), which lobbies on behalf of the sector, says Britain is now at the forefront of new technology, with a legislative framework in place that offers the opportunity for long-term investment.
Projects are proceeding in the US, such as the experimental coal-fired Mountaineer plant in West Virginia, which began small-scale carbon capture last year, as well as in Canada, China and other countries.
Jeff Chapman, chief executive of the CCSA, believes Economides has made inappropriate assumptions about the science and geology. He believes the conclusions in the paper are wrong and says his views are backed up by rebuttals from the Lawrence Berkeley National Laboratory, the Pacific Northwest National Laboratory and the American Petroleum Institute (API).
The British Geological Survey confirmed it was looking at the Economides findings and was hoping to produce a peerreviewed analysis shortly. Economides, who has a PhD from Stanford University, said he had seen the arguments against his paper from the API and dismissed them as ‘nonsense”, saying vested interests are protecting a new concept foisted on the world by geologists without proper thought.
‘I was a [practising] petroleum engineer for many years and soon realised that geologists did not understand flow and the laws of physics, against which you can’t argue.”
Chapman pointed out that Statoil, a Norwegian oil company, had been injecting CO2 into an old reservoir on the North Sea Sleipner field for some time as a successful experiment in carbon storage. But Economides says the Sleipner scheme involved a million tonnes over three years, while one 500MW commercial station would need to absorb and store three million tonnes annually for 25 years.
Economides, who admits he veers towards being something of a climate change sceptic, says the oil and coal industries see these schemes as potential solutions so they can keep on doing what they have been doing in the past, but ‘CCS is the last refuge of the scoundrel,” he said.—