Carbon capture and storage

Carbon Capture and Storage (CCS) refers to technology allowing for zero greenhouse emissions from coal production. The technology is centres on the capture of greenhouse emissions post combustion and their storage in the Earth's crust.

=Technology Overview=

Terms such as zero emissions and low emissions coal technologies are misleading, coal generation will continue to produce GHG's from combustion or gasification. For a coal technology to be considered low emissions, the emissions must be physically captured, transported and sequestered in the Earth's crust. The coal industry are promoting two technologies as clean, Oxyfuel and Coal Gasification.

Existing coal plants
Existing coal plants are generally located in close proximity to a Coalmine, this is due to the very low value of coal (typically $20-$30/tonne). Consideration needs to be given to sites where the carbon is to be stored, this may be a great distance from the site of the coal plant. Also existing plants will need to derate their performance, boilers, generators and crushers will have been designed to handle a certain quantity of coal, it is likely that the capture and storage of coal could be very energy intensive and so the plants net energy production may be significantly reduced. It is also likely that the retrofitting will not suit all coal plants, if it can be done at all it may only suit small generators and those designed specifically with CCS in mind.

New coal plants
CCS power plants will need to be sited both in terms of proximity to a source of coal and in terms of proximity to a suitable location for the storage of GHG's. Capital costs are likely to rise significantly, as is the cost of production. Current technology does not meet the requirements of large scale power plants and so it is also likely that new constructions will be lower efficiency and lower capacity than present technology.

=Carbon storage=


 * Capacity of geosequestration in porpous rock
 * Limited to rare and remote sites
 * Used to increase the capacity of oil and gas fields?
 * What about leakage
 * How to monitor?
 * Solubility of carbon in water
 * Capacity becomes limitless
 * But what about environmental impacts?

=Environmental impacts=


 * Increased coal mining - and associated environmental damage
 * Underground gasification - very scary stuff!
 * Carbon leakage from storage sites
 * Dissolving CO2 in groundwater
 * Storage of carbon in the ocean.

=Economic analysis=


 * Capital expenditure of CCS equipment
 * Cost of pipelines
 * Cost of Air separation units
 * Increased running costs
 * Projection of price of electricity due to CCS

=See Also=
 * CCS Demonstration Projects