It sounds such a simple idea. Take the carbon dioxide emissions from coal-fired power stations, store them underground and prevent global warming. The trouble is, it’s not as simple as that.

Carbon Capture and Storage (CCS) has got politicians excited. It’s based on technology already used in the oil industry. Energy companies pump carbon dioxide into oil reservoirs so that they can raise the pressure and extract more oil and gas.

Once the oil or gas have been extracted, the companies haven’t, in the main, been too worried about what happens to the carbon dioxide afterwards. However, now some of them are testing to see whether the carbon dioxide remains underground.

It’s difficult to know whether the carbon dioxide will mix with subterranean
water and react with the minerals in the ground. It’s like the carbon dioxide in a fizzy drink dissolving the calcium carbonate in teeth. Greenpeace calculates that a 1% leakage rate would cause 63% of the carbon dioxide in any storage unit to be released within 100 years.

But it’s cost that remains the real sticking point. Adding to CCS technology to power stations is expensive. About a quarter of the power generated by a CCS-equipped power station is used in the chemical capture of the carbon dioxide, its compression and transport. Subsequently, CCS power stations will need to be about a third bigger to generate the same power as an equivalent conventional power station.

Many governments are hoping that CCS technology will improve and become less expensive. In 2008, the European Union required its members to draw up rules for CCS within two years. But it’s unlikely that this deadline will be met.

So for CCS, it’s a matter of watch this space.

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