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Iceland Geothermal
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Why “technically possible” is not the same as “practical”

News this week that scientists in Iceland have found a new method for storing carbon dioxide was hailed as a climate change breakthrough.  But was it really?  In fact there are very good reasons for pessimism.

Carbon Capture and Storage (CCS) technology is at the heart of emissions reduction policies across the developed world.  The idea is that we continue (more or less) with business as usual until about 2030; by which time we will have developed CCS technologies to allow us to continue burning coal, gas and oil without adding to atmospheric carbon dioxide.  But, thus far CCS remains little more than a fantasy.

In this light, the achievements in Iceland appear promising at first sight.  By mixing carbon dioxide with water, the scientists created an acidic liquid that will rapidly react with minerals in basalt rock to lock the carbon up in new rock.  Scientists at the International Panel on Climate Change had assumed that this process could take up to 1,000 – making it wholly unsuitable as a means of storing carbon.  However, the Iceland research found that up to 98 percent of the carbon had been locked into rock within just two years.

Problem solved, you might think.  However, there are several grounds for caution.  First, the “storage” side of CCS is likely to be the easiest to deploy.  The “capture” side, by contrast has proved far too difficult and costly for anyone to attempt it commercially.  Indeed, UK CCS projects, like the ones at Drax and Aberthaw were cancelled the moment government subsidies were withdrawn.  And if you think retrofitting a coal power station to capture carbon is difficult, imagine what it is going to cost to retrofit carbon scrubbers on all of the vehicles we use.

The second problem comes from accessing basalt.  The Icelandic study was able to use boreholes that were already in place at one of Iceland’s geothermal plants.  So the cost of drilling was avoided.  Any large scale use of basalt for storing carbon would necessarily involve drilling on an industrial scale – which would itself add significant volumes of carbon dioxide to the atmosphere.

Third, the volumes of water required (25 tons for every ton of carbon dioxide) rule the process out for most of humanity simply because we do not have access to that much fresh water (salt water would interfere with the chemical reactions involved.)

Finally, and despite all of the advantages in Iceland, the process was far too expensive to carry out commercially.  That additional cost has to come from elsewhere.  For scientific research, it is paid through general taxation (allocated by a government department).  At a commercial scale, this type of storage would have to be included in the cost of energy – making it too costly to the end user… we’re still better off using less energy and deploying renewables to battle climate change.

In fact, as we reported here earlier this year, the chemistry of using some types of rock to sequester carbon dioxide is nothing new.  Scientists already know that it is technically possible.  But this is not the same as making it work in practice; because if something costs too much (usually a proxy for using up too much energy, labour, capital and resources) then it will not be done.

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