Carbon capture and storage

Written by David Howarth MP and published in Lib Dem News on Wed 30th May 2007

An emerging theme in energy policy is the growing importance of the idea of carbon capture and storage as a way of reducing carbon emissions from electricity generation.

The idea of carbon capture and storage is simple - instead of releasing carbon dioxide into the atmosphere, where it contributes to climate change, we should pump it back underground, where it does no harm. Carbon capture and storage can reduce carbon emissions from fossil fuel power stations by 90%.

Capturing the carbon can take place either by separating CO2 out of the exhaust gases of conventional gas or coal power stations, or by gasifying the fuel first and separating the CO2 out before combustion. According to the International Panel on Climate Change, both methods are economic given the right conditions - for example a carbon price of around the levels recommended by Sir Nicholas Stern. Other methods, including the 'oxy-fuel' method, are at an earlier stage of development, but show promise.

Potential storage includes existing oil and gas wells and coal mines with seams too difficult to mine. Another possibility, which recent research has shown to be credible, is to use saline aquifers. There is probably enough storage space with minimal risk of leakage to take, at the lowest estimate, 50 years of output and, at the highest, several centuries' worth. More speculative is the idea of storing CO2 in lakes at the bottom of the sea. If that works, the amount of storage would be very great indeed.

Transferring the CO2 would be by pipeline where possible and by ship where not.

The practical engineering is, of course, not so simple, but, as a spokesperson for Scottish and Southern Energy said last month, "All the technology is proven at the desired scale - we are only demonstrating the ability to integrate technologies."

The advantage of carbon capture and storage is that, although not a fully sustainable technology in itself (since the gas and coal will run out eventually) it does buy us time to switch to a fully renewable and low energy-using system without having to resort to nuclear power. Carbon capture does not share nuclear power's notorious problems - for example its connection with nuclear weapons proliferation, a fuel of use to terrorists, its need for hidden subsidies such as a cap on liability for accidents and its inflexibility in changing output to match the needs of the grid. Carbon capture works better than nuclear with renewables and with efforts to reduce energy consumption.

The trouble is that carbon capture and nuclear are in direct competition as transitional technologies. In terms of timing, for example, both will be fully available only in the 2020s. The government's announcement that it favours nuclear has therefore dealt a blow to carbon capture. One of the first business reactions to the government's energy white paper was that BP announced the suspension of its carbon capture joint venture with Scottish and Southern at Peterhead. The government's rhetoric that we can have it all in energy - nuclear, carbon capture and renewables - has been shown instantly to be false. Their choice for nuclear is already undermining all the other options.