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Carbon Capture and Storage (CCS) Factfile
Key points
 This is not an energy source but a way of dealing with CO2 emissions
 It is only practical to use CCS at power stations or large industrial sites
 Adds costs to the electricity generated as facilities need to be constructed, operated and
15-30% more fuel used for same output
 Has not yet been shown to work on a large scale
Background information
 Carbon capture and storage, or CCS, is a technology that involves:
o the capture of carbon dioxide (CO2) from burning a fuel or industrial processes,
o the transport of that CO2 via ships or pipelines, and
o its storage underground, in depleted oil and gas fields and deep saline formations
[1].
 This prevents the CO2 from contributing to climate change.
 CCS could be particularly useful for capturing CO2 emissions from electricity generation
using coal or gas.
 If the CO2 from burning sustainably grown biomass (wood etc) were captured, over time this
could produce negative emissions or “carbon sequestration”, reducing the amount of CO2
in the atmosphere.
Current use in world and UK
World
 Currently CCS has only been put to use at industrial scale in a small number of places.
 Most of the active ones are in industry, such as when natural gas is processed.
 Large-scale systems are starting to be built to go with electricity production, with about 30
projects being developed, mainly in the US, Europe and Southeast Asia [2].
Britain
 In the UK, there are no active CCS systems but several projects are being developed.
These include:
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o a new coal-fired power station fitted with CCS,
o a project to retrofit a gas-fired power station with CCS
o a mixed coal and biomass power station fitted with CCS.
 CO2 storage for these projects are:
o empty oil and gas fields
o offshore saline formations (underground rocks with porous spaces filled with salt
water)
 A pipeline infrastructure is being developed by National Grid for the transport of CO2 [2].
Climate change and impact on nature
Climate change
 CCS technology has the potential to greatly reduce emissions from fossil fuel power
stations, or even help remove some CO2 from the atmosphere if sustainably grown
biomass is used as the fuel.
 CCS cannot capture all of the CO2 from a power station - some CO2 is still emitted. Carbon
capture efficiency of about 90% is considered most likely.
 Lifecycle CO2 emissions are estimated to be about:
o 75 gCO2e/kWh for gas CCS and
210-230 grams of CO2 or equivalent greenhouse gas per kilowatt-hour (gCO2e/kWh)
for coal CCS
Direct emissions from combustion are about
o 40 gCO2e/kWh for gas CCS and
o 120 gCO2e/kWh for coal CCS
Remaining lifecycle emissions relate mainly to fuel supply.
 The process of capturing the CO2 means that about 15-30% more fuel is used per kWh of
electricity generated than for power stations without CCS, so fuel supply emissions are
therefore higher [3].
Other environmental impacts
 The other impacts on nature from CCS are fairly small, with the construction and
maintenance of pipelines to carry CO2 being the main impact, and these should have little
impact once completed.
 All the impacts of mining coal or extracting gas still apply when these are used as fuels.
 As 15-30% more fuel is required to run the CCS systems and supply the same amount of
electricity than in a power station without CCS, the impacts of obtaining the fuel are
greater.
Risks
Climate change risk
 A key risk would be if the stores of CO2 were to leak rapidly. This would release CO2 into
the atmosphere possibly causing rapid, unpredicted climate change.
 This is considered very unlikely to occur if the geology is correctly assessed, suitable
storage sites chosen, and correct storage methods used [4].
 Since storage of CO2 is a large additional cost, the risk of shortcuts being taken must be
strongly guarded against.
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Risks to humans
 Risks in building and maintaining CCS infrastructure are similar to other forms of energy
industry operations in similar situations.
 All the risks of mining coal or extracting gas still apply when these are used as fuels with
CCS.
 For coal powered electricity generation with CCS, the impacts on human health from other
air pollutants are changed, in comparison with coal powered electricity generation without
CCS:
o sulphur dioxide emissions are reduced
o nitrogen oxide and particulate matter are expected to increase in line with additional
fuel used
o ammonia pollution is expected to increase as it is a product of the CO2 capture
process [5]
Cost now and in the future
 It is estimated that CCS power stations could produce electricity at a cost of about:
o 9 pence per kWh for gas CCS and
o 10p/kWh for coal CCS.
 This compares to about 6p/kWh for gas or coal electricity generation without CCS.
 If carbon taxes are increased as expected in future then coal with CCS electricity
generation could become cheaper than coal generation without CCS and similar in cost to
gas generation without CCS [6, 7].
 Electricity generation with CCS would though be even more affected by rises in fossil fuel
prices as 15-30% more fuel is required per unit of electricity produced.
World and UK resource
World
 The limiting factor in using CCS is to identify and develop enough sites for CO2 storage,
and to develop the network of pipelines to connect power stations to this storage.
 The United Nations Intergovernmental Panel on Climate Change estimates the world’s
potential capacity at two trillion tonnes of CO2, and there could be a “much larger
potential” [4].
 This compares with annual emission of CO2 from fossil fuels of around 35 billion tonnes.
Britain
 The UK has a good potential resource for storing CO2. Estimates suggest that about:
o 3,500 million tonnes of CO2 could be stored in old oil and gas fields, and
o 4,600 to 46,000 million tonnes of CO2 could be stored in ‘saline aquifers’ (rock
saturated with salty water) [8].
Using the low end of the estimate for saline aquifers, this is enough to store all the CO2
emissions from current UK electricity generation for around 50 years.
Reliability/flexibility
 As long as fuel supplies can be maintained, CCS should provide a reliable way to generate
electricity and safely store most, but not all, of the CO2 emissions.
 The technology is yet to be demonstrated on a large scale.
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 CCS is flexible in that it can be applied to a range of fuels, including gas, coal and biomass
[2]. In theory, CCS power plants could be flexible in their output of electricity, although in
practice, given the large investment cost, plant operators will want to run CCS power
stations as much as possible.
 The flexibility of CCS is limited by the fact that CCS facilities can only be built where they
can be connected by a pipeline network to adequate CO2 storage.
 It is only practical to use CCS at power stations or large industrial sites.
 CCS can’t be used to capture the emissions from the millions of petrol and diesel vehicles
or gas boilers in homes.
Wales
The first and only carbon capture and storage facility in Wales operated at Aberthaw Power Station
in the Vale of Glamorgan but has now finished [10].
Aberthaw
Power Station
It was planned to capture 50 tonnes of carbon dioxide per day from the flue gases of the 1.5 GW
coal power station on the site. This is equivalent to the daily emissions of a 3 MW coal power
station (RWE, 2014). [9]
References
[1] IEA (undated). topic: carbon capture and storage. International Energy Agency. http://www.iea.org/topics/ccs/
[accessed 16/1/2014].
[2] Global CCS Institute (undated). Large-scale Integrated CCS Projects. Global CCS Institute.
http://www.globalccsinstitute.com/projects/browse [accessed 16/1/2014].
[3] CCC (2013). Reducing the UK’s carbon footprint and managing competitiveness risks. The Committe on Climate
Change. http://www.theccc.org.uk/publication/carbon-footprint-and-competitiveness/ [accessed 14/1/2014].
[4] Global CCS Institute (undated). How CCS works - storage. Global CCS Institute.
http://www.globalccsinstitute.com/understanding-ccs/how-ccs-works-storage [accessed 16/1/2014].
[5] EEA (2011). Carbon capture and storage could also impact air pollution. European Environment Agency.
http://www.eea.europa.eu/highlights/carbon-capture-and-storage-could [accessed 16/1/2014].
[6] CCC (2010). The Fourth Carbon Budget – reducing emissions through the 2020s. The Committee on Climate
Change. http://www.theccc.org.uk/publication/the-fourth-carbon-budget-reducing-emissions-through-the-2020s-2/
[accessed 9/1/2014].
[7] DECC (2012). Electricity Generation Costs. Department for Energy and Climate Change.
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/65713/6883-electricity-generationcosts.pdf [accessed 9/1/2014].
[8] CCC (2011). The Renewable Energy Review. The Committee on Climate Change.
http://www.theccc.org.uk/publication/the-renewable-energy-review/ [accessed 16/1/2014].
[9] Link to project website:
http://www.rwe.com/web/cms/en/2756/rwe/innovation/projects-technologies/power-generation/fossil-fired-powerplants/co2-removal-uk/
[10] email from Aberthaw Power Station 31/3/2015
– background information for Energy Trumps cards. Full resource available as free download at
http://learning.cat.org.uk/en/resources
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