Geoscience Reference
In-Depth Information
Carbon capture and storage
Removal of carbon dioxide during industrial processes can be tricky and costly, because
not only does the gas need to be removed, but it must be stored somewhere as well. In the
UK the world's first carbon capture and storage (CCS) demonstration project called White
Rose has been commissioned. White Rose will be part of the Drax Power Station site near
Selby, North Yorkshire, generating electricity for the UK as well as capturing approxim-
ately 2 million tonnes of carbon dioxide per year, some 90 per cent of all carbon dioxide
emissions produced by the plant. The carbon dioxide will be transported through the Na-
tional Grid's proposed pipeline for permanent undersea storage in the North Sea. The pro-
ject is being financially supported by both the European Commission (~£250 million) and
the UK government (~£100 million). This large-scale project is being carried out to demon-
strate that the technology does work and that CCS has a key role to play in reducing future
carbon dioxide emissions.
UK and EU financial support is required, as removal and storage costs could be somewhere
between $10 and $50 per tonne of carbon dioxide. This would cause a 15 per cent to 100
per cent increase in power production costs. However, recovered carbon dioxide does not
all need to be stored; some may be utilized in enhanced oil recovery, the food industry,
chemical manufacturing (producing soda ash, urea, and methanol), and the metal-process-
ing industries. Carbon dioxide can also be applied to the production of construction materi-
al, solvents, cleaning compounds, and packaging, and in waste-water treatment. However,
in reality, most of the carbon dioxide captured from industrial processes would have to be
stored. It has been estimated that theoretically two-thirds of the carbon dioxide formed
from the combustion of the world's total oil and gas reserves could be stored in the corres-
ponding reservoirs. Other estimates indicate storage of 90-400 Gt in natural gas fields
alone and another 90 Gt in aquifers.
Oceans could also be used to dispose of the carbon dioxide. Suggestions have included
storage by hydrate dumping—if you mix carbon dioxide and water at high pressure and
low temperatures, it creates a solid, or hydrate, which is heavier than the surrounding water
and thus drops to the bottom. Another more recent suggestion is to inject the carbon diox-
ide half a mile deep into shattered volcanic rocks in between giant lava flows. The carbon
dioxide will react with the water percolating through the rocks. The acidified water will
dissolve metals in the rocks, mainly calcium and aluminium. Once it forms calcium bicar-
bonate with the calcium, it can no longer bubble out and escape. Though if it does escape
into the ocean, then bicarbonate is relatively harmless. With ocean storage there is the ad-
