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{{publication  

{{publication  

  | image  = ST59_lg.jpg

  | image  = ST59_lg.jpg

  | width  = 120px

  | width  = 400px

  | series  = Studies in Geology

  | series  = Studies in Geology

  | title  = Carbon dioxide sequestration in geological media: State of the science

  | title  = Carbon dioxide sequestration in geological media: State of the science

  | isbn    = 0-89181-0668

  | isbn    = 0-89181-0668

}}

}}

[[Coal]], [[Oil as an energy source|oil]], and [[natural gas]] currently supply about 85% of the world's [[energy]] needs. Moreover, given the relatively low cost and abundance of [[fossil fuel]]s together with the huge sunken investment in fossil-fuel-based infrastructure, fossil fuels will likely continue to be used for at least the next 25 to 50 years. The burning of fossil fuels is, however, the major source of anthropogenic (man-made) carbon dioxide (CO₂). Carbon dioxide is the main greenhouse gas released to the atmosphere.<ref name=IPCC_2005 />

[[Coal]], [[oil]], and [[natural gas]] currently supply about 85% of the world's [[energy]] needs. Moreover, given the relatively low cost and abundance of [[fossil fuel]]s together with the huge sunken investment in fossil-fuel-based infrastructure, fossil fuels will likely continue to be used for at least the next 25 to 50 years. The burning of fossil fuels is, however, the major source of anthropogenic (man-made) carbon dioxide (CO₂). Carbon dioxide is the main [[greenhouse gas]] released to the atmosphere.<ref name=IPCC_2005 />

Geosequestration, also known as carbon capture and storage (CCS), is a means to reduce anthropogenic CO₂ emissions to the atmosphere. Geosequestration involves the long-term storage of captured CO₂ emissions in deep subsurface geological [[reservoir]]s. Carbon sequestration can be pursued as part of a portfolio of [[greenhouse gas]] abatement options, when this portfolio also includes improving the conservation and efficiency of energy use and utilizing nonfossil energy forms such as renewable ([[Solar energy|solar]], [[wind]], and [[tidal]]) and [[Nuclear power|nuclear energy]].<ref name=Kaldi_2005>Kaldi, J. G., 2005, Geosequestration: Australian Institute of Geoscientists Quarterly Newsletter, v. 80, p. 1–6.</ref> Geosequestration may contribute significant reductions to anthropogenic CO₂ emissions. Estimates by the Intergovernmental Panel on Climate Change indicate that a technical potential of at least about 2000 billion metric tonnes of CO₂ storage capacity in geological formations likely exists (Table 1).<ref name=IPCC_2005 />

[[Geosequestration]], also known as carbon capture and storage (CCS), is a means to reduce anthropogenic CO₂ emissions to the atmosphere. Geosequestration involves the long-term storage of captured CO₂ emissions in deep subsurface geological [[reservoir]]s. Carbon sequestration can be pursued as part of a portfolio of greenhouse gas abatement options, when this portfolio also includes improving the conservation and efficiency of energy use and utilizing nonfossil energy forms such as renewable ([[Solar energy|solar]], [[wind]], and [[tidal]]) and [[Nuclear power|nuclear energy]].<ref name=Kaldi_2005>Kaldi, J. G., 2005, Geosequestration: Australian Institute of Geoscientists Quarterly Newsletter, v. 80, p. 1–6.</ref> Geosequestration may contribute significant reductions to anthropogenic CO₂ emissions. Estimates by the Intergovernmental Panel on Climate Change indicate that a technical potential of at least about 2000 billion metric tonnes of CO₂ storage capacity in geological formations likely exists (Table 1).<ref name=IPCC_2005 />

{| class = "wikitable"

{| class = "wikitable"

| Deep saline formations || 1000 || Uncertain but possibly 10,000

| Deep saline formations || 1000 || Uncertain but possibly 10,000

|}

|}

<span style="font-size:8pt">''*The storage capacity includes storage options that are not economical.<ref name=IPCC_2005>Intergovernmental Panel on Climate Change (IPCC), 2005, IPCC special report on carbon dioxide capture and storage, prepared by Working Group III of the IPCC (B. Metz, O. Davidson, H. C. de Connick, M. Loos, and L. A. Meyer, eds): New York, Cambridge University Press, 442 p.</ref> **These numbers would increase by 25% if undiscovered oil and gas fields were included in this assessment. ***ECBM = enhanced coalbed methane.''</span>

^{* The storage capacity includes storage options that are not economical.<ref name=IPCC_2005>Intergovernmental Panel on Climate Change (IPCC), 2005, IPCC special report on carbon dioxide capture and storage, prepared by Working Group III of the IPCC (B. Metz, O. Davidson, H. C. de Connick, M. Loos, and L. A. Meyer, eds): New York, Cambridge University Press, 442 p.</ref>}<br>

^{**These numbers would increase by 25% if undiscovered oil and gas fields were included in this assessment.}<br>

^{***ECBM = enhanced coalbed methane.''}

[[file:GeosequestrationProcess.JPG|thumb|400px|{{figure number|1}}A simplified view of the steps involved in the geosequestration process (image courtesy of Cooperative Research Centre for Greenhouse Gas Technologies [CO2CRC]).<ref name=Kaldietal_2009>Kaldi, J. G., C. M. Gibson-Poole, and T. H. D. Payenberg, 2009, Geological input to selection and evaluation of CO₂ geosequestration sites, in M. Grobe, J. C. Pashin, and R. L. Dodge, eds., Carbon dioxide sequestration in geological media—State of the science: AAPG Studies in Geology 59 , p. 5–16.</ref>]]

[[file:GeosequestrationProcess.JPG|thumb|400px|{{figure number|1}}A simplified view of the steps involved in the geosequestration process (image courtesy of Cooperative Research Centre for Greenhouse Gas Technologies [CO2CRC]).<ref name=Kaldietal_2009>Kaldi, J. G., C. M. Gibson-Poole, and T. H. D. Payenberg, 2009, [http://archives.datapages.com/data/specpubs/study59/CHAPTER01/CHAPTER01.HTM Geological input to selection and evaluation of CO₂ geosequestration sites], in M. Grobe, J. C. Pashin, and R. L. Dodge, eds., Carbon dioxide sequestration in geological media—State of the science: [http://store.aapg.org/detail.aspx?id=739 AAPG Studies in Geology 59], p. 5–16.</ref>]]

Geosequestration comprises several steps: first, the CO₂ is captured at the source, which can be a power plant or other industrial facility; the captured CO₂ is then transported, typically via pipeline, from the source to the geological storage site; next, the CO₂ is injected deep underground via wells into the geological reservoir; and finally, the CO₂ is stored in the geological reservoir, where its movement is carefully monitored and the quantity stored is regularly verified ([[:file:GeosequestrationProcess.JPG|Figure 1]]). The capture, transport, and injection processes do require additional energy to be expended (and hence more CO₂ is emitted); however, the net CO₂ emission reduction is still a significantly large volume to make deep reductions in anthropogenic greenhouse gas emissions. For example, a power plant with CCS could reduce net CO₂ emissions to the atmosphere by approximately 80–90% compared to a plant without CCS ([[:file:CO2EmissionsComparison.JPG|Figure 2]]).<ref name=IPCC_2005 />

Geosequestration comprises several steps: first, the CO₂ is captured at the source, which can be a power plant or other industrial facility; the captured CO₂ is then transported, typically via pipeline, from the source to the geological storage site; next, the CO₂ is injected deep underground via wells into the geological reservoir; and finally, the CO₂ is stored in the geological reservoir, where its movement is carefully monitored and the quantity stored is regularly verified ([[:file:GeosequestrationProcess.JPG|Figure 1]]). The capture, transport, and injection processes do require additional energy to be expended (and hence more CO₂ is emitted); however, the net CO₂ emission reduction is still a significantly large volume to make deep reductions in anthropogenic greenhouse gas emissions. For example, a power plant with CCS could reduce net CO₂ emissions to the atmosphere by approximately 80–90% compared to a plant without CCS ([[:file:CO2EmissionsComparison.JPG|Figure 2]]).<ref name=IPCC_2005 />

==Carbon dioxide injection==

==Carbon dioxide injection==

Carbon dioxide injection involves taking the CO₂ from the surface and injecting it deep underground into a [[reservoir rock]]. The CO₂ is injected into the reservoir via a single well or array of wells. Both [[enhanced oil recovery]] (EOR) using [[carbon dioxide flood]]s and [[acid gas injection]] (AGI) are mature technologies that involve significant quantities of CO₂ being injected underground and are therefore very good analogs for CO₂ injection as part of geosequestration activities. The first project using CO₂ for EOR began in 1972, and by 1999, 84 operational projects worldwide existed (72 in the United States) injecting an estimated total of more than 15 million tonnes of CO₂ per year.<ref name=EPRI_1999>Electric Power Research Institute (EPRI), 1999, [http://www.energy.ca.gov/process/pubs/electrotech_opps_tr113836.pdf Enhanced oil recovery scoping study, final report], October 1999, TR-113836 (accessed August 10, 2007).</ref>

Carbon dioxide injection involves taking the CO₂ from the surface and injecting it deep underground into a [[reservoir]] rock. The CO₂ is injected into the reservoir via a single well or array of wells. Both [[enhanced oil recovery]] (EOR) using [[carbon dioxide flood]]s and [[acid gas injection]] (AGI) are mature technologies that involve significant quantities of CO₂ being injected underground and are therefore very good analogs for CO₂ injection as part of geosequestration activities. The first project using CO₂ for EOR began in 1972, and by 1999, 84 operational projects worldwide existed (72 in the United States) injecting an estimated total of more than 15 million tonnes of CO₂ per year.<ref name=EPRI_1999>Electric Power Research Institute (EPRI), 1999, [http://www.energy.ca.gov/process/pubs/electrotech_opps_tr113836.pdf Enhanced oil recovery scoping study, final report], October 1999, TR-113836 (accessed August 10, 2007).</ref>

[[File:CO2StorageOptions.JPG|thumb|400px|{{figure number|3}}|Options for the geological storage of CO2 (image courtesy of Cooperative Research Centre for Greenhouse Gas Technologies [CO2CRC]).<ref name=Kaldietal_2009 />]]

[[File:CO2StorageOptions.JPG|thumb|400px|{{figure number|3}}|Options for the geological storage of CO2 (image courtesy of Cooperative Research Centre for Greenhouse Gas Technologies [CO2CRC]).<ref name=Kaldietal_2009 />]]