Wednesday, 9 September 2009

UK could be CO2 sink for Europe

UK could be the CO2 sink for Europe, capitalising on the potential for carbon capture under the North Sea, said a professor this week speaking at the British Science Festival

Professor Stuart Haszeldine has urged the government to capitalise on the UK’s current position as world leader in carbon capture and storage technology.

Speaking at the British Science Festival on Tuesday, Professor Haszeldine emphasised the need for policy makers and industry not to be “faint hearted when it comes to the practical stuff”.

The UK Department of Energy and Climate Change aims to put four plants into operation between 2015 and 2018, but Professor Haszeldine thinks more ambitious targets should be set. He would like to see five plants active by 2016, to demonstrate to industry that the technology works and can be profitable.

The UK has a huge, but as yet unexploited natural asset – microscopic spaces in the rocks beneath the North Sea. Professor Stuart Haszeldine and Dr Mike Stephenson explained the role this could play in locking underground CO2 produced by power stations.

Carbon capture and storage (CCS) has the potential to reduce the amount of CO2 pumped out by fossil fuel fired power stations by up to 90 per cent, making it a powerful weapon in the drive to curb carbon emissions. It is particularly important as a ‘bridging technology’, providing breathing space before renewable sources are able to meet global energy demand.

In CCS, the CO2 produced from burning coal and gas is trapped in special units attached to power stations, liquefied and piped out to sea. There it is pumped 1000 metres under the sea bed, into the tiny spaces between the grains of sandstone rocks. To stop the gas from escaping upwards, storage sites must have a ‘lid’ of impermeable rock. Possible sites include depleted offshore oil and gas fields and salt water aquifers.

The amount of space potentially available in the North Sea is massive and few other countries have such extensive reservoirs available. Professor Haszeldine, of the University of Edinburgh, estimates around 150 billion tons of CO2 could be stored in the UK, equivalent to 100 years worth of emissions from north-west Europe. Following the example of Texas, which markets itself as ‘the CO2 sink for the USA’, it is hoped that the UK can sell storage to other countries.

Concerns have been raised over the possibility of massive CO2 leakages hundreds of years in the future. In the case of depleted gas fields, Dr Stephenson of the British Geological Survey argued that as natural gas has stayed safely buried for millions of years, why shouldn’t the CO2?

Seismic imaging is used to monitor the underground CO2 and check it is stable. Evidence from the Sleipner field, which has been used as an underground CO2 store since 1996, suggests that the CO2 is indeed confined securely.

CCS is one of the cheapest options in the search for clean energy supplies, and although capturing CO2 and forcing it underground is not without energy costs these are expected to fall over coming years. Professor Haszeldine predicts that by 2020 the cost will only add £28 to a typical household electricity bill of £498.

Source: The New Civil Engineer

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