Potential for carbon sequestration in a low-carbon-emission world

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Potential for carbon sequestrationin a
low-carbon-emission world
AAAS19 Feb 2005

• Ken CaldeiraEnergy Environment
  DirectorateLawrence Livermore National
  Laboratorykenc_at_llnl.gov

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What is carbon sequestration?

• Storage of carbon in a reservoir1 so as to keep
  carbon dioxide out of the atmosphere
• 1e.g., geologic, oceans, biomass,etc.

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IPCC Taxonomy

• Carbon storage
• Physics and chemistry-based approaches
• Geologic, oceans, etc.
• Carbon sequestration
• Biology-based approaches
• Land biomass, ocean fertilization, etc.

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A 5000 PgC emission trajectory and emissions
stabilizing CO2 at 550 ppm
Caldeira and Wickett, JGR, submitted
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CO2-stabilization requires a huge abatement effort
Abatement required (PgC/yr)
Year2055 Year2105
3 24 128
2.5 17 76
2 12 44
1.5 8 24
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CO2-stabilization requires a huge abatement effort
Integrated abatement required (PgC)
Year2055 Year2105
3 450 3600
2.5 340 2400
2 250 1500
1.5 170 900
For 1.5 to 2 growth in energy demand
Emissions to be avoided 900-1500 PgC up to year
2105
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Three complementary strategiesto CO2
stabilization
CO2stabilization
Developnon-fossilenergy sources
Sequestercarbon
Diminishend-usedemand
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A taxonomy of carbon storage options
Carbonsequestration
Removal from point sources
Removal fromatmosphere
Geologicinjection
Oceaninjection
Landbiomass
Oceanfertilization
Silicatemineralweathering
Carbonatemineralweathering
EngineeredatmosphericCO2 removal
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Capture and compression are the drivers of cost
and energy penalties
Year 2000 IGCC PC NGCC
/KwH (busbar) 1.70 3.32 1.61
Energy penalty () 14.6 25.0 13.0
/tonne CO2 avoided 26 49 49
IGCC Integrated coal Gasification, Combined
CyclePC Pulverized Coal, simple cycleNGCC
Natural Gas, Combined Cycle Estimates by David
and Herzog (2000)
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Increasing efficiency diminishes cost and energy
penalties
Year 2012 IGCC PC NGCC
/KwH (busbar) 1.04 2.16 1.23
Energy penalty () 9.0 15.0 10.0
/tonne CO2 avoided 18 32 41
IGCC Integrated coal Gasification, Combined
CyclePC Pulverized Coal, simple cycleNGCC
Natural Gas, Combined Cycle Estimates by David
and Herzog (2000)
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Some geologic storage options
www.co2captureproject.com
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Can we find an environmentally and economically
acceptable way to isolatefossil-fuel CO2 from
the atmosphere?
Atmosphere 750 PgC
Oil 130
Gas 120
PgC
PgC
Coal
5,000 to 8,000 PgC
Tar sands, organic carbon rich shales, methane
hydrates, etc.  ???
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Carbon dioxide storage capacities
Emissions to be avoided 900-1500 PgC up to year
2105
Source Moomaw et al, IPCC, 2001
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Estimated capacity is the same order-of-magnitude
as anticipated demand
Emissions to be avoided 900-1500 PgC up to year
2105
DOE Roadmap 1998
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CO2 Burial Saline Reservoirs
Different test sequestration projects 2002-2004

• Mountaineer Project
• AEP/Battelle
• Mt Simon Fm.
• NOT closure dependent -- dynamic sequestration

• S. Texas
• DOE/U. Texas
• Frio Trend
• closure dependent already mapped
• Small (2000 tons)

DOE, 1999
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India and China
Almost 40of world population Large coal
resources, consumption Few oil/gas
resources Growing auto industry
Growth of developing nation energy, esp. China
and India, will be coal-based, requiring CO2
storage options that are affordable.
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Sleipner Vest Utsira Formation
FIRST major attempt an large volume CO2
sequestration, offshore Norway. Active since
1996. Monoethanolamine (MEA) capture
Geol. Survey of Denmark Greenland
Operator Statoil Partners Norsk-Hydro, Petoro,
Shell-Esso, Total-Elf-Fina
Economic driver Norwegian carbon tax on industry
(50/ton C) makes this commercial Cost of
storage 15/ton C
Target 1 MM ton CO2/yr. So far, 6 MM tons
http//www.statoil.com
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Sleipner mathematics

• 1 Sleipner 106 tCO2/yr 270,000 tC/yr
• 1 Sleipner per day for the next 50 years 5
  PgC/yr
• Abatement needed with 2 energy demand growth
  12 PgC/yr in 50 years

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Risk of CO2 Leakage
CO2 is less dangerous than natural gas.Risks in
piping, etc., are real but manageable
Leakage risk may be greatest from poorly sealed
drill holes penetrating cap rock Possibility of
accumulation in topographic depressions in
quiescent weather conditions (public acceptance?)
Crystal Geyser CO2 leak
Photograph by Zoe Shipton, Trinity College Dublin
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Monitoring geologic storage

• Given the potential for leakage, surface
  monitoring is required. For any site, multiple
  techniques will be needed to cover a range of
  conditions within a given footprint.
• areal techniques
• point techniques
• inside homes
• These should be tailored to 100 m surface
  expression

town
Courtesy J. Friedmann
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Geologic carbon storage

• Capacity of the same order-of-magnitude as known
  fossil-fuel resources
• Saline aquifers main storage reservoir
• Some capacity in depleted oil and gas wells, coal
  seams
• Basic technology already exists
• Opportunity to bring down costs with RD
• Perhaps, 2/3 of power plants in the USA could
  store CO2 in geologic formations without long
  pipelines
• Few potential reservoirs have been characterized
• Risk of leaks thought to be manageable (public
  acceptance?)

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Can we find an environmentally and economically
acceptable way to isolatefossil-fuel CO2 from
the atmosphere?
Atmosphere 750 PgC
Oil 130
Gas 120
PgC
PgC
Coal
5,000 to 8,000 PgC
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Can we find an environmentally and economically
acceptable way to isolatefossil-fuel CO2 from
the atmosphere?
Atmosphere 750 PgC
Oil 130
Gas 120
Vegetation
PgC
PgC
600 PgC
Coal
Soils 1,000 to 1,500 PgC
5,000 to 8,000 PgC
Oceans
40,000 PgC
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Permanent vs. temporary storage

• Some approaches, i.e., geologic storage, can be
  effectively permanent
• Other approaches, i.e., ocean CO2 injection and
  land biosphere storage, are temporary

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Permanent vs. temporary storage

• Temporary storage has value (but is not as
  valuable as permanent storage)
• Economic perspective
• Temporary storage is equivalent to delayed
  emission
• Value depends on economic discount rates and
  future cost of CO2 emissions
• Climate perspective
• Temporary storage can help buy time to develop
  more-permanent solutions

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Ocean storage
Various methodshave been designed to inject
separated and compressed CO2 into the deep ocean
Figure courtesy P. Johnston
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We already have an ocean carbon storage policy
IPCC Special Report (in prep.)
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Most coasts are near the deep ocean
Red dots represent OCMIP injection simulation
locations
Caldeira and Wickett, JGR, submitted
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A 5000 PgC emission trajectory and emissions
stabilizing CO2 at 550 ppm
Caldeira and Wickett, JGR, submitted
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A 5000 PgC emission trajectory, WRE550, and the
use of ocean storage to get from one to the other
CO2 release to ocean
CO2 release to atmosphere
Caldeira and Wickett, JGR, submitted
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The use of ocean storage
Caldeira and Wickett, JGR, submitted
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Inorganic sinks for CO2 emissions to the
atmosphere

• CO2 absorption by surface ocean
• 1 yr
• CO2 H2O ? H HCO3
• Mixing to deep ocean
• 300 yr
• Carbonate dissolution
• 6000 yr
• CO2 CaCO3 H2O ? Ca2 2HCO3
• Silicate-rock weathering
• 300,000 yr
• CO2 CaSiO3 ? CaCO3 SiO2

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Salt water aquarium-keepers maintain healthy
coral growth by circulating tank water through a
reactor that uses CO2 to dissolve limestone
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Accelerated carbonate weathering

• Bring CO2-rich waste gas in contact with seawater
  in a reactor vessel at a power plant to produce
  carbonic acid
• CO2 H2O ? H HCO3
• use this carbonic acid to dissolve crushed
  limestone
• H HCO3 CaCO3 ? Ca2 2HCO3
• dilute the resulting solution in the
  near-surface ocean

Experiments led by Kevin Knauss, LLNL
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CaCO3 neutralizationand ocean chemistry

• Dissolution of CaCO3 can mitigate many, but not
  all, chemical effects of excess CO2
• If deployed on a large scale, would require huge
  amount of limestone (order of 1 m3 per ton CO2)

Caldeira and Wickett, JGR, submitted
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Can we find an environmentally and economically
acceptable way to isolatefossil-fuel CO2 from
the atmosphere?
Atmosphere 750 PgC
Oil 130
Gas 120
Vegetation
PgC
PgC
600 PgC
Coal
Soils 1,000 to 1,500 PgC
5,000 to 8,000 PgC
Oceans
40,000 PgC
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Land biosphere carbon storage

• Approaches
• Forest regrowth
• Agricultural practices to increase soil carbon
  storage (e.g., no-till)

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Forest regrowth

• Carbon stored in forests 13.1 kg / m2
• (Birdsey, 1992)
• 1 PgC 76,000 km2
• maintained indefinitely or harvested and stored

Emissions to be avoided 900-1500 PgC up to year
2105
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Forest regrowth may store carbon, but warm the
world
Regrowing forests storecarbon cooling effect
but the dark forest canopy absorbs more
sunlight warming effect Net effect is warming
inthis calculation
Schematic model calculation Caldeira, in prep.
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Carbon storage in the land biosphere

• Good points
• Technically ready now, room for RD improvement
• Low-tech, can be applied in developing world
  (e.g., no till practices)
• Direct climate effects of tropical forests is
  cooling
• Can have ancillary benefits (e.g., biodiversity,
  soil retention)
• Bad points
• Upper bound for increase 10 x 2,000 PgC 200
  PgC
• Storage is temporary (gt50 yr?)
• Land intensive
• Direct climate effects of afforestation in mid-
  and high-latitudes can overwhelm carbon storage
  gains

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A taxonomy of carbon storage options
Carbonsequestration
Removal from point sources
Removal fromatmosphere
Geologicinjection
Oceaninjection
Landbiomass
Oceanfertilization
Silicatemineralweathering
Carbonatemineralweathering
EngineeredatmosphericCO2 removal
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Enabling technologies

• Constraints limit application of carbon storage
  options
• Geographic mismatch of power demand and potential
  storage sites
• Long-distance electricity transmission
• Capture and storage options unlikely to be
  economic for small, mobile, CO2 sources
• Hydrogen or electric cars

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Conclusions

• Carbon capture and storage (sequestration) has
  the potential to eliminate most of the CO2 from
  fossil-fuel burning
• To be affordable beyond centralized power plants,
  enabling technologies must be developed, such as
  long-distance electricity transmission and H2 (or
  electric) cars
• Geologic storage is the most promising strategy
  for large-scale and long-term storage, but other
  approaches will probably find niche applications

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