CO2 removal from the atmosphere Lead authors: Mark Workman1 and Niall McGlashan1 Other contributors: Nilay Shah1, Mark Flower1, Jon Gibbins2 and Hannah Chalmers2,*

1
CO2 removal from the atmosphereLead authors
Mark Workman1 and Niall McGlashan1Other
contributors Nilay Shah1, Mark Flower1, Jon
Gibbins2 and Hannah Chalmers2,

• 1Imperial College London
• 2Imperial College London (visiting) and
  University of Edinburgh
• hannah.chalmers02_at_imperial.ac.uk,
  hannah.chalmers_at_ed.ac.uk
• AVOID session 2, Earth Systems Science 2010
• Edinburgh, 12th May 2010

2
Context

• A robust strategic plan is needed for 80 cuts in
  GHG emissions by 2050
• Need to allow for emissions that are difficult to
  reduce in agriculture, some transport sectors etc
• Useful to have options available for an
  emergency where stock of CO2 in atmosphere is
  too high
• Some CO2 emissions abatement options are
  expensive, so search for alternatives continues
• A range of options for removing CO2 from the
  atmosphere have been identified
• Some approaches to CO2 removal from the
  atmosphere could increase options available due
  to potential flexibility in location for
  deployment

3
Preliminary illustrative numbers

• Technical potential for CO2 abatement at prices
  below 200/tCO2...
• ...and could be (significantly?) below 100/tCO2
• Number of individual units depends on technology
  approach chosen, e.g. dispersed/centralised
  choice?
• Klaus Lackner artificial trees
• Could need around 1.5million units for 10 of UK
  CO2 emissions
• 1ppm global contribution estimated to require lt2
  of current global electricity demand
• Biomass enhanced CCS (BECCS) could have negative
  emissions potential of at least 10 of current
  UK CO2 emissions by 2030
• Need to consider international trade for maximum
  contribution
• Full lifecycle analysis remains challenging

4
Class 1 Class 2 Class 3 CCS projects
Class 1 carbon positive CCS Class 2 (near)
carbon neutral CCS Class 3 carbon negative
CCS Class 1 Usually producing hydrocarbons,
CCS gets the carbon footprint down to
conventional hydrocarbon levels e.g. LNG,
coal-to-liquids, oil sands Class 2 Producing
carbon free energy vectors electricity,
hydrogen or heat Class 3B Biomass plus CCS
(takes CO2 from the air) Class 3A Technology to
process air directly to capture CO2 Enhanced oil
recovery (EOR) and replacing natural gas
reinjected in oil fields are grey areas.
Chalmers, H., Jakeman, N., Pearson, P. and
Gibbins, J. (2009) CCS deployment in the UK
What next after the Government competition?,
Proc. I.Mech.E. Part A Journal of Power and
Energy, 223(3), 305-319.
5
Class 3AA

• CO2 removed directly from the air and stored as
  CO2
• Large enough potential to pursue further
• Need to find sufficient low carbon energy sources
  
• Scale-up to be done

Sources for pictures IMechE (2009), Keith et al
(2006)
6
Class 3AA

• CO2 removed directly from the air and stored as
  CO2
• Large enough potential to pursue further
• Need to find sufficient low carbon energy sources
  
• Scale-up to be done

Also note some details can be missed in artistic
impressions! - Need to handle/process caustic
soda solution (including potential crashes) -
Wind turbines have shed blades in other places
(unusual, but has happened at Whitelee, Scotland
this year)
Sources for pictures IMechE (2009), Keith et al
(2006)
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Class 3AB

• CO2 removed directly from the air and fixed in a
  stable material
• Further work on monitoring, verification and
  reporting needed
• Co-benefits also being explored (reversing ocean
  acidification, soil improvement)
• Reasonable potential, but time needed for scale-up

Sources for pictures Kruger (2010), Lehmann et
al (2006)
8
Class 3B

• Biomass enhanced CCS (BECCS)
• Can be stand-alone use of biomass or
  co-firing/gasification
• Fuel diversity (geography and feedstock)
  important to counteract seasonal availability and
  regional surpluses
• Must be sensitive to competing uses and land use
  change
• Can make non-trivial contribution now/soon and
  unlikely to have CO2 storage capacity constraint
  in UK context

9
Emerging conclusions

• A mix of options could be viable at reasonable
  scale for removing CO2 from the atmosphere
• Flexibility in location could be helpful to avoid
  large CO2 transport systems
• Costs could be reasonable and may allow a cap on
  CO2 emission trading/tax costs
• Some options could be significant by 2030, while
  others may need longer to scale-up
• For technologies to be available asap, pilot and
  scale-up support will be needed