1 iron fertilization, air capture, and geoengineering woods hole, ma 26 september 2007 david keith...
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Iron Fertilization, Air Capture,and Geoengineering
Woods Hole, MA
26 September 2007
David Keith ([email protected]; www.ucalgary.ca/~keith)
Director, Energy and Environmental Systems GroupInstitute for Sustainable Energy, Environment and Economy
University of Calgary
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New York Times May 24th 1953
Emissions are rising faster than expected
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Skeptics argued that this “unrealistic” scenario was included only to make the problem look worse
This is where we need to be heading
And, it’s melting quicker than models predict
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Ice cover on16 September 2007
minimum ice cover 1979-2000
Hum an actions tha tchange clim ate
C lim ateSystem
Clim ate im pact on hum an we lfa re
G eoeng ineering Adapta tionM itigation
Hum an actions tha tchange clim ate
C lim ateSystem
Clim ate im pact on hum an we lfa re
G eoeng ineering Adapta tionM itigation
Hum an actions tha tchange clim ate
C lim ateSystem
Clim ate im pact on hum an we lfa re
C lim a te im p acto n n a tu ra l w o rld (P o lar B e a rs)
Carbon Management: Location vs Mechanism
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Biomass Energy with Capture
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Biomass with Capture
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Electricity for free…
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0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0
C a rb o n p r ice ($ /tC )
Cos
tofe
lect
ricity
(c/k
Wh)
C o a l
N a tu ra l g a s
B io m as s
C o s t o f a ir ca p tu re w ithc u r re n t e le c tr ic i ty p r ice s
B io m as sw ith C O c ap tu re2
… at a ~300 $/tC carbon price
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Air Capture
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Thermodynamics of CO2 capture
Free energy of mixing:
To get 1 bar it takes:~ 6 kJ/mol starting at 10% CO2 in a power plant exhaust, and
~ 20 kJ/mol starting at the 380 ppm ambient atmospheric concentration
It takes ~13 kJ/mol to compress from 1 to 100 bar
C + 2 O2 CO2 394 kJ/mol
Power plants are ~35% efficient (~160 kJe/mol-C from coal)min loss of electric output should be ~12% ((6+13)/160).
Current designs are at least twice as bad.
0ln pkT p
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Direct Air Capture
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A
A
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Cost and energy use vs flow rate
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Negative emissions change long-run climate policy
300
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2000 2050 2100 2150 2200 2250
ppm
v C
O2
Year
Unlucky
Lucky
Reference
Air cap
Air cap
Keith, D. W., Ha-Duong, M. & Stolaroff, J. K. Climate strategy with CO2 capture from the air. Climatic Change (2005).
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Air Capture Summary
1. Three uses • Long run negative emissions (2100?).• Acting in a rush, AC along while we do Coal CCS (2030?) • Low Carbon Fuels and remote EOR (2015?)
2. NaOH contactor• ETH/Rome group using commercial data on packed towers.• Calgary/CMU using spray tower
• Less than $50/tCO2
3. NaOH regen• Nuclear heat• Electrochemical• Borates/Titenates• No good end-to-end costing.
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Other Methods
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Increasing ocean alkalinity
Motivation: 2×[CO3-2] + [HCO3
-] [A]
• Mg-silicates
– Olivine (Mg2SiO4) and serpentine (Mg3Si2O5(OH)4) are the most abundant Mg-silicates
• MgO
• CaCO3
• CaO
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Comparisons
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