Carbon Capture and Storage in Sub-Seabed Geological Formations

Carbon Capture and Storage (CCS) may be one of the most promising approaches to reducing CO2 concentrations in the atmosphere in the short and medium term.  CCS generally involves the capture of carbon dioxide (CO2) directly from industrial or power plant fossil-fueled sources -- CO2 that would otherwise enter the atmosphere and eventually penetrate into deep ocean waters.  Capture is then followed by removal of the CO2 to secure subsurface reservoirs for long-term storage, either on land or beneath the seabed of the ocean.   

Efforts to reduce CO2 concentrations in the atmosphere may call for very substantial contributions from CCS in the coming years.  Appropriate regulatory structures will be needed.  The use of geological formations on land or in waters subject to national jurisdiction will generally be subject to national law.  However, the use of geological formations beneath the seabed beyond national jurisdiction raises transboundary issues and issues with respect to the protection of the global commons.  And there are other challenges.  Costs will be high and the regulatory climate needs to be supportive while, at the same time, ensuring the protection of the environment.  See Vidas, H., B. Hugman, A. Chikkatur, B. Venkatesh.  2012.  Analysis of the Costs and Benefits of CO2 Sequestration on the U.S. Outer Continental Shelf.  U.S. Department of the Interior, Bureau of Ocean Energy Management.  Herndon, Virginia.  OCS Study BOEM  2012-100, Ch. 5 and 6.


At the international level, measures have been enacted under the London Convention/London Protocol and the regional Convention for the Protection of the Marine Environment of the North-East Atlantic (the OSPAR Convention) to regulate the injection of carbon dioxide into sub-seabed geologic formations for the purpose of climate change mitigation.

London Convention/London Protocol

In 2005, the Parties to the London Convention and London Protocol began discussing CCS in relation to the ocean.  LC.2/Circ. 439 (Mar. 31, 2005).  The London Convention (1972) is the original ocean dumping convention.  Its goal was to control sources of marine pollution and to take all practical steps to prevent pollution of the ocean by the dumping of wastes.  The U.S. is a party to the London Convention   The London Protocol (1996) strengthened the Convention and will eventually replace it.  The U.S. is not a party to the London Protocol.  The Parties to these two instruments were concerned, among other things, about the effect of climate change on the marine environment and the pace of ocean acidification caused by elevated concentrations of CO2 in the atmosphere.  They recognized that one option for addressing this trend was CO2 sequestration in sub-seabed geological formations.  However, Annex 1 of the Protocol, which listed wastes or other matter that may be considered for dumping, did not list CO2.  At the time, sequestration in deep seabed geological formations was considered dumping.

On November 2, 2006, the Contracting Parties amended Annex 1 of the London Protocol in order to regulate CO2 sequestration.  Under the rule, CO2 streams may only be considered for disposal if (a) it is disposal into a sub-seabed geological formation (not into the ocean itself); (b) the streams consist overwhelmingly of CO2 (except for incidental associated substances); and (c) no waste is added for the purpose of disposal.  These amendments entered into force for the Parties to the Protocol on February 10, 2007.

The Parties then produced two sets of guidelines.  In November 2006, they adopted a “Risk Assessment and Management Framework for CO2 Sequestration in Sub-Seabed Geological Structures” which reflected the following structure: (a) Problem Formulation, (b) Site Characterization, (c) Exposure Assessment, (d) Effects Assessment, (e) Risk Characterization, and (f) Risk Management.  This was followed in November 2007 with “Specific Guidelines for Assessment of Carbon Dioxide Streams for Disposal into Sub-Seabed Geological Formations” (Sequestration  Guidelines)  (amended 2012) which advised the Parties on how to capture and sequester CO2 in a manner that is safe for the marine environment over both the short and long term.  The Sequestration Guidelines are to be used in conjunction with Guidelines for the Assessment of Waste or Other Matter that may be Considered for Dumping (Generic Guidelines) which were adopted by the Parties in 1997 and which “embody mechanisms to guide national authorities in evaluating applications for  dumping of waste in a manner consistent with the provisions of [the LC and LP].”   Generic Guidelines at 2.  A specific CO2 reporting format was adopted in October 2008, see IMO Report LC/SG 31/16 (Annex 8). Article 6 of the London Protocol was amended in October 2009 to enable Parties to export carbon dioxide streams for purpose of sequestration in transboundary sub-seabed geological formations.  This amendment for CO2 must be ratified by 31 London Protocol Parties.  As of 2017, only three Parties have ratified it.

The OSPAR Convention

The Convention for the Protection of the Marine Environment of the North-East Atlantic, or the OSPAR Convention, was opened for signature in 1992 and entered into force in 1998.  Fifteen nations and the European Commission are Parties to OSPAR.  The U.S. is not a Party.  As with the London Protocol, OSPAR specifies what may be dumped in the Northeast Atlantic marine environment.  This is done under two Annexes to the Convention -- Annex II and Annex III.

In light of the amendment of the London Protocol, the Parties to OSPAR began in 2006 to work on their own amendment.  This resulted in a guidance document entitled the OSPAR Guidelines for Risk Assessment and Management of Storage of CO2 Streams in Geological Formations. The Guidelines included a “Framework” for Risk Assessment and Management for Risk Assessment and Management of CO2 Streams in Geological Formations (Annex 1 to the Guidelines).  The Framework is similar to the London Protocol’s 2006 Risk Assessment and Management Framework.  

The following year, in June 2007, OSPAR was amended by consensus of the Parties to allow the storage of carbon dioxide in geological formations under the seabed.  These Carbon Capture and Storage measures entered into force in 2011.  Amendments of Annex II and Annex III to the Convention in Relation to the Storage of Carbon Dioxide Streams in Geological Formations, Summary Record OSPAR 07/24/1 -E Annex 4 (2007).  The amendments were similar to the London Protocol’s but added one condition.   Under the London Protocol, storage must be in sub-soil geological formations, must consist overwhelmingly of CO2, and no wastes or other matter may be added for disposal.   OSPAR adds that CO2 is “intended to be retained permanently and will not lead to significant adverse consequences for the marine environment, human health and other users.”  OSPAR  Convention Annex II, Art.3 (June 2007).  In addition, OSPAR adopted a Decision to prohibit “[t]he placement of carbon dioxide streams in the water column or on the seabed….”  OSPAR Decision 2007/1,  Convention Annex 5 (June 2007).


Additional References

DOE Selects Projects for Offshore Storage Assessment (2015)
DOE, National Energy Technology Laboratory: Carbon Storage Technology Page
Report of the Interagency Task Force on Carbon Capture and Storage (2010)
International Energy Agency, Legal and Regulatory Review (2012)
International Energy Agency, 20 Years of Carbon Capture and Storage: Accelerating Future Deployment (2016)
OECD/IEA, Carbon Capture and Storage and the London Protocol:  Options for Enabling Transboundary CO2 Transfer (2011)

Last updated 10/12/2017