Table TS.12. Differences in the forms of CCS and biological sinks that might influence the way accounting is conducted.

Property Terrestrial biosphere Deep ocean Geological reservoirs
CO2 sequestered or stored Stock changes can be monitored over time. Injected carbon can be measured. Injected carbon can be measured.
Ownership Stocks will have a discrete location and can be associated with an identifiable owner. Stocks will be mobile and may reside in international waters. Stocks may reside in reservoirs that cross national or property boundaries and differ from surface boundaries.
Management decisions Storage will be subject to continuing decisions about land- use priorities. Once injected there are no further human decisions about maintenance once injection has taken place. Once injection has taken place, human decisions about continued storage involve minimal maintenance, unless storage interferes with resource recovery.
Monitoring Changes in stocks can be monitored. Changes in stocks will be modelled. Release of CO2 can be detected by physical monitoring.
Expected retention time Decades, depending on management decisions. Centuries, depending on depth and location of injection. Essentially permanent, barring physical disruption of the reservoir.
Physical leakage Losses might occur due to disturbance, climate change, or land-use decisions. Losses will assuredly occur as an eventual consequence of marine circulation and equili- bration with the atmosphere. Losses are unlikely except in the case of disruption of the reservoir or the existence of initially undetected leakage pathways.
Liability A discrete land-owner can be identified with the stock of sequestered carbon. Multiple parties may contribute to the same stock of stored CO2 and the CO2 may reside in international waters. Multiple parties may contribute to the same stock of stored CO2 that may lie under multiple countries.

Source: IPCC  Carbon Dioxide Capture and Storage: Technical Summary (2005)
9. Emission inventories and accounting, p. 44

Related publication:
CO2 Capture & Storage homeCO2 Capture and Storage
Other Figures & Tables on this publication:

Table TS.1. Current maturity of CCS system components. An X indicates the highest level of maturity for each component. There are also less mature technologies for most components.

Table TS.2. Profile by process or industrial activity of worldwide large stationary CO2 sources with emissions of more than 0.1 MtCO2 per year.

Table TS.3. Summary of CO2 capture costs for new power plants based on current technology. Because these costs do not include the costs (or credits) for CO2 transport and storage, this table should not be used to assess or compare total plant costs for different systems with capture. The full costs of CCS plants are reported in Section 8.

Table TS.4. Summary of CO2 capture costs for new hydrogen plants based on current technology

Table TS.5. Sites where CO2 storage has been done, is currently in progress or is planned, varying from small pilots to large-scale commercial applications.

Table TS.6. Storage capacity for several geological storage options. The storage capacity includes storage options that are not economical.

Table TS.7. Fraction of CO2 retained for ocean storage as simulated by seven ocean models for 100 years of continuous injection at three different depths starting in the year 2000.

Table TS.8. Costs for ocean storage at depths deeper than 3,000 m.

Table TS.9. 2002 Cost ranges for the components of a CCS system as applied to a given type of power plant or industrial source. The costs of the separate components cannot simply be summed to calculate the costs of the whole CCS system in US$/CO2 avoided. All numbers are representative of the costs for large-scale, new installations, with natural gas prices assumed to be 2.8-4.4 US$ GJ-1 and coal prices 1-1.5 US$ GJ-1.

Table TS.10. Range of total costs for CO2 capture, transport and geological storage based on current technology for new power plants using bituminous coal or natural gas

Table TS.11. Mitigation cost ranges for different combinations of reference and CCS plants based on current technology for new power plants. Currently, in many regions, common practice would be either a PC plant or an NGCC plant14. EOR benefits are based on oil prices of 15 - 20 US$ per barrel. Gas prices are assumed to be 2.8 -4.4 US$/GJ-1, coal prices 1-1.5 US$/GJ-1 (based on Table 8.3a).

Table TS.12. Differences in the forms of CCS and biological sinks that might influence the way accounting is conducted.

Figure TS.1. Schematic diagram of possible CCS systems

Figure TS.2a. Global distribution of large stationary sources of CO2

Figure TS.2b. Prospective areas in sedimentary basins

Figure TS.3. Overview of CO2 capture processes and systems

Figure TS.4. (a) CO2 post-combustion capture at a plant in Malaysia

Figure TS.5. Transport costs for onshore pipelines and offshore pipelines

Figure TS.6. Costs, plotted as US$/tCO2 transported against distance, for onshore pipelines, offshore pipelines and ship transport

Figure TS.7. Methods for storing CO2 in deep underground geological formations

Figure TS.8. Potential leakage routes and remediation techniques for CO2 injected into saline formations

Figure TS.9. Methods of ocean storage

Figure TS.10. Material fluxes and process steps associated with the mineral carbonation of silicate rocks or industrial residues (Courtesy ECN).

Figure TS.11. CO2 capture and storage from power plants

Figure TS.12. Global potential contribution of CCS as part of a mitigation portfolio

Figures TS.2a. & TS.2b.