CO2 removal from the atmosphere
Lead authors: Mark Workman1 and Niall McGlashan1
Other contributors: Nilay Shah1, Mark Flower1,
Jon Gibbins2 and Hannah Chalmers2,*
1Imperial
College London
2Imperial College London (visiting) and University of Edinburgh
*hannah.chalmers02@imperial.ac.uk, hannah.chalmers@ed.ac.uk
AVOID session 2, Earth Systems Science 2010
Edinburgh, 12th May 2010
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
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 <2% 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
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.
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)
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)
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)
Class 3B
(e) GHG Emissions
(a) Biomass Feedstock
Production:
(b) Harvesting, Storage,
Processing, Transport
(c) Bio Energy Power Plant
(f) Fossil Fuel Energy Displaced
(d) Carbon Capture and
Sequestration
• 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
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