View source for Carbon capture and storage

{{Short description|Process of capturing and storing carbon dioxide from industrial flue gas}}
{{about|capturing CO<sub>2</sub> directly from industrial facilities and power plants|processes that remove and sequester CO<sub>2</sub> from the atmosphere|Carbon dioxide removal}}
{{good article}}
[[File:CBO-how-carbon-capture-works.png|thumb|With CCS, carbon dioxide is captured from a point source, such as an ethanol refinery. It is usually transported via pipelines and then either used to [[Enhanced oil recovery|extract oil]] or stored in a dedicated geologic formation. |alt=Diagram showing a coal plant and an ethanol plant at the surface, connected to pipes. The pipes go through several underground layers to depleted oil reservoirs and to saline formations. A pipe connects the oil reservoir to an oil rig at the surface and another pipe away from the oil rig is labelled "to market". ]]
{{Use dmy dates|date=May 2022}}

'''Carbon capture and storage''' ('''CCS''') is a process by which [[carbon dioxide]] (CO<sub>2</sub>) from industrial installations is separated before it is released into the atmosphere, then transported to a long-term storage location.<ref name=":9">IPCC, 2021: [https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_AnnexVII.pdf Annex VII: Glossary] [Matthews, J.B.R., V. Möller, R. van Diemen, J.S. Fuglestvedt, V. Masson-Delmotte, C.&nbsp; Méndez, S. Semenov, A. Reisinger (eds.)]. In [https://www.ipcc.ch/report/ar6/wg1/ Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change] [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 2215–2256, doi:10.1017/9781009157896.022.</ref>{{Rp|page=2221}} The CO<sub>2</sub> is captured from a large [[point source pollution|point source]], such as a [[natural gas processing plant]] and is typically stored in a deep [[geological formation]]. Around 80% of the CO<sub>2</sub> captured annually is used for [[enhanced oil recovery]] (EOR), a process by which CO<sub>2</sub> is injected into partially depleted oil reservoirs in order to extract more oil and then is largely left underground.<ref name=":13">{{Cite journal |last1=Zhang |first1=Yuting |last2=Jackson |first2=Christopher |last3=Krevor |first3=Samuel |date=2024-08-28 |title=The feasibility of reaching gigatonne scale CO<sub>2</sub> storage by mid-century |journal=Nature Communications |language=en |volume=15 |issue=1 |pages=6913 |doi=10.1038/s41467-024-51226-8 |issn=2041-1723 |pmc=11358273 |pmid=39198390|bibcode=2024NatCo..15.6913Z }}[[File:CC-BY_icon.svg|50x50px]] Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref> Since EOR {{Em|utilizes}} the CO<sub>2</sub> in addition to {{Em|storing}} it, CCS is also known as '''carbon capture, utilization, and storage''' ('''CCUS''').<ref name=":113" /> 

Oil and gas companies first used the processes involved in CCS in the mid 20th century. Early CCS technologies were mainly used to purify natural gas and increase oil production. Beginning in the 1980s and accelerating in the 2000s, CCS was discussed as a strategy to [[climate change mitigation|reduce greenhouse gas emissions]]. Around 70% of announced CCS projects have not materialized,<ref name=":13" /> with a failure rate above 98% in the electricity sector.<ref name=":23" /> As of 2024 CCS was in operation at 44 plants worldwide,<ref name=":21" /> collectively capturing about one-thousandth of global carbon dioxide emissions.<ref name=":2" /> 90% of CCS operations involve the oil and gas industry.<ref name=":28" />{{Rp|page=15}} Plants with CCS require more energy to operate, thus they typically burn additional fossil fuels and increase the pollution caused by extracting and transporting fuel.
         
CCS could have a critical but limited role in reducing [[greenhouse gas emissions]].<ref name=":2" /> However, other emission-reduction options such as solar and wind energy, [[electrification]], and public transit are less expensive than CCS and are much more effective at reducing air pollution. Given its cost and limitations, CCS is envisioned to be most useful in specific niches. These niches include [[heavy industry]] and plant retrofits.<ref name=":44" />{{Rp|page=|pages=21–24}} In the context of deep and sustained cuts in natural gas consumption,<ref>{{Cite web |title=Executive summary – Net Zero Roadmap: A Global Pathway to Keep the 1.5 °C Goal in Reach – Analysis |url=https://www.iea.org/reports/net-zero-roadmap-a-global-pathway-to-keep-the-15-0c-goal-in-reach/executive-summary |access-date=2024-11-10 |website=IEA |language=en-GB}}</ref> CCS can reduce emissions from [[Natural-gas processing|natural gas processing]].<ref name=":44" />{{Rp|page=|pages=21–24}} In electricity generation and [[hydrogen production]], CCS is envisioned to complement a broader shift to renewable energy.<ref name=":44" />{{Rp|page=|pages=21–24}} CCS is a component of [[bioenergy with carbon capture and storage]], which can under some conditions remove carbon from the atmosphere.     

The effectiveness of CCS in reducing carbon emissions depends on the plant's capture efficiency, the additional energy used for CCS itself, leakage, and business and technical issues that can keep facilities from operating as designed. Some large CCS implementations have sequestered far less CO<sub>2</sub> than originally expected.<ref name=":14" /><ref name=":2" /> Controversy remains over whether using captured CO<sub>2</sub> to extract more oil ultimately benefits the climate.<ref name=":27" /> Many environmental groups regard CCS as an unproven, expensive technology that perpetuates [[fossil fuel]] dependence. They believe other ways to reduce emissions are more effective and that CCS is a distraction.<ref name=":73" />

Some international climate agreements refer to the concept of '''fossil fuel abatement''', which is not defined in these agreements but is generally understood to mean use of CCS.<ref name=":11" /> Almost all CCS projects operating today have benefited from government financial support. Countries with programs to support or mandate CCS technologies include the US, Canada, Denmark, China, and the UK.{{TOC limit|3}}

== Terminology ==

The [[Intergovernmental Panel on Climate Change]] (IPCC) defines CCS as:<blockquote>"A process in which a relatively pure stream of carbon dioxide (CO<sub>2</sub>) from industrial and energy-related sources is separated (captured), conditioned, compressed and transported to a storage location for long-term isolation from the atmosphere."<ref name=":9"/>{{Rp|page=2221}}</blockquote>The terms ''carbon capture and storage'' (CCS) and ''carbon capture, utilization, and storage'' (CCUS) are closely related and often used interchangeably.<ref name=":113">{{Cite journal |last1=Sekera |first1=June |last2=Lichtenberger |first2=Andreas |date=6 October 2020 |title=Assessing Carbon Capture: Public Policy, Science, and Societal Need: A Review of the Literature on Industrial Carbon Removal |journal=Biophysical Economics and Sustainability |volume=5 |issue=3 |pages=14 |bibcode=2020BpES....5...14S |doi=10.1007/s41247-020-00080-5 |issn= |doi-access=free}}Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref> Both terms have been used predominantly to refer to [[enhanced oil recovery]] (EOR) a process in which captured CO<sub>2</sub> is injected into partially-depleted oil reservoirs in order to extract more oil.<ref name=":113" /> EOR is both "utilization" and "storage", as the CO<sub>2</sub> left underground is intended to be trapped indefinitely. Prior to 2013, the process was primarily called ''CCS.'' In 2013 the term ''CCUS'' was introduced to highlight its potential economic benefit, and this term subsequently gained popularity.<ref name=":113" />

Around 1% of captured CO<sub>2</sub> is used as a feedstock for making products such as fertilizer, fuels, and plastics.<ref>{{Cite journal |last1=Martin-Roberts |first1=Emma |last2=Scott |first2=Vivian |last3=Flude |first3=Stephanie |last4=Johnson |first4=Gareth |last5=Haszeldine |first5=R. Stuart |last6=Gilfillan |first6=Stuart |date=November 2021 |title=Carbon capture and storage at the end of a lost decade |url=https://linkinghub.elsevier.com/retrieve/pii/S2590332221006096 |journal=One Earth |volume=4 |issue=11 |pages=1645–1646 |bibcode=2021OEart...4.1645M |doi=10.1016/j.oneear.2021.10.023 |issn=2590-3322 |access-date=2024-06-21 |hdl-access=free |hdl=20.500.11820/45b9f880-71e1-4b24-84fd-b14a80d016f3}}</ref> These uses are forms of ''carbon capture and utilization''.<ref name=":232">{{Cite web |title=CO2 Capture and Utilisation - Energy System |url=https://www.iea.org/energy-system/carbon-capture-utilisation-and-storage/co2-capture-and-utilisation |access-date=2024-06-27 |website=IEA |language=en-GB}}</ref> In some cases, the product durably stores the carbon from the CO<sub>2</sub> and thus is also considered to be a form of CCS. To qualify as CCS, carbon storage must be long-term, therefore utilization of  CO<sub>2</sub>  to produce fertilizer, fuel, or chemicals is not CCS because these products release CO<sub>2</sub> when burned or consumed.<ref name=":232" />

Some sources use the term ''CCS, CCU, or CCUS'' more broadly, encompassing methods such as [[direct air capture]] or tree-planting which [[Carbon dioxide removal|remove CO<sub>2</sub> from the air.]]<ref name=":522">{{Cite journal |last1=Snæbjörnsdóttir |first1=Sandra Ó |last2=Sigfússon |first2=Bergur |last3=Marieni |first3=Chiara |last4=Goldberg |first4=David |last5=Gislason |first5=Sigurður R. |last6=Oelkers |first6=Eric H. |date=February 2020 |title=Carbon dioxide storage through mineral carbonation |url=https://www.nature.com/articles/s43017-019-0011-8 |journal=Nature Reviews Earth & Environment |volume=1 |issue=2 |pages=90–102 |bibcode=2020NRvEE...1...90S |doi=10.1038/s43017-019-0011-8 |issn=2662-138X |access-date=2024-06-21}}</ref><ref>{{Cite journal |last1=Hepburn |first1=Cameron |last2=Adlen |first2=Ella |last3=Beddington |first3=John |last4=Carter |first4=Emily A. |last5=Fuss |first5=Sabine |last6=Mac Dowell |first6=Niall |last7=Minx |first7=Jan C. |last8=Smith |first8=Pete |last9=Williams |first9=Charlotte K. |date=November 2019 |title=The technological and economic prospects for CO<sub>2</sub> utilization and removal |url=https://www.nature.com/articles/s41586-019-1681-6 |journal=Nature |language=en |volume=575 |issue=7781 |pages=87–97 |doi=10.1038/s41586-019-1681-6 |pmid=31695213 |bibcode=2019Natur.575...87H |issn=1476-4687}}</ref><ref>{{Cite web |date=2021-04-07 |title=About CCUS – Analysis |url=https://www.iea.org/reports/about-ccus |access-date=2024-08-24 |website=IEA |language=en-GB}}</ref> In this article, the term ''CCS'' is used according to the IPCC's definition, which requires CO<sub>2</sub> to be captured from point-sources such as a natural gas processing plant.

== History and current status ==
[[File:20210413 Carbon capture and storage - CCS - proposed vs implemented.svg|thumb|upright=1.25 | Global proposed (grey bars) vs. implemented (blue bars) annual {{CO2}} captured. Both are in million tons of CO<sub>2</sub> per annum (Mtpa). More than 75% of proposed CCS installations for [[natural-gas processing]] have been implemented.|alt=Diagram titled "Proposed vs. implemented CO2 capture". Y axis is "Millions tons CO2 captured". X axis is years from 2000 to 2020. Chart shows a strong upward trend for "Proposed, not implemented" and a much smaller trend for "Implemented". Highest percentage of proposals implemented are for natural gas processing, then other industrial, then power.]]
[[File:2000- Patents covering carbon capture and storage (CCS) technologies.svg |thumb |upright=1.25 |The number of patents covering CCS technologies surged in the 2000s, but stalled or declined in the 2010s.<ref name=CCS_patents_2000>{{cite web |title=Annual patents filed for carbon capture and storage technologies |url=https://ourworldindata.org/grapher/patents-ccs?tab=chart |publisher=Our World in Data |date=2022 |archive-url=https://web.archive.org/web/20250106181535/https://ourworldindata.org/grapher/patents-ccs?tab=chart |archive-date=6 January 2025 |url-status=live}} (Click "chart" tab) Source states: "Data source: IRENA - INSPIRE Platform (2022) / Data for the most recent years are not complete due to a lag between the filing date and the time at which the patents are officially published. Further information can be found on IRENA INSPIRE."</ref>]]
[[File:Bełchatów Elektrownia.jpg |thumb |upright=1.25 |Plans to add CCS to Poland's [[Bełchatów Power Station]] were cancelled in 2013.<ref>{{cite web|last1=STEFANINI|first1=SARA |title=Green Coal in the Red|url=https://www.politico.eu/article/paperthe-eus-failed-ccs-ambitions/ |website=Politico|date=21 May 2015|accessdate=21 November 2017}}</ref>  Over 98% of plans to use CCS in [[Power station|power plants]] have failed.<ref name=":23">{{Cite journal |last1=Kazlou |first1=Tsimafei |last2=Cherp |first2=Aleh |last3=Jewell |first3=Jessica |date=October 2024 |title=Feasible deployment of carbon capture and storage and the requirements of climate targets |journal=Nature Climate Change |language=en |volume=14 |issue=10 |pages=1047–1055, Extended Data Fig. 1 |doi=10.1038/s41558-024-02104-0 |pmid=39386083 |issn=1758-6798|pmc=11458486 |bibcode=2024NatCC..14.1047K }}</ref> |alt=Aerial view of the Belchatow Power Station site, with smoke coming from its smokestacks, and surrounding buildings.]]

In the natural gas industry, technology to [[Natural-gas processing|remove CO<sub>2</sub> from raw natural gas]] was patented in 1930.<ref name= "rochelle">{{Cite journal |last=Rochelle |first=Gary T. |date=2009-09-25 |title=Amine Scrubbing for CO 2 Capture |url=https://www.science.org/doi/10.1126/science.1176731 |journal=Science |language=en |volume=325 |issue=5948 |pages=1652–1654 |doi=10.1126/science.1176731 |pmid=19779188 |issn=0036-8075|url-access=subscription }}</ref> This processing is essential to make natural gas ready for commercial sale and distribution.<ref name=":44">IEA (2020), ''[https://www.iea.org/reports/ccus-in-clean-energy-transitions CCUS in Clean Energy Transitions]'', IEA, Paris [[File:CC-BY_icon.svg|50x50px]] Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref>{{Rp|page=25}} Usually after CO<sub>2</sub> is removed, it is vented to the atmosphere.<ref name=":44" />{{Rp|page=25}} In 1972, American oil companies discovered that  CO<sub>2</sub> could profitably be used for EOR.<ref>{{Cite web |last=United States Office of Fossil Energy and Carbon Management |date= |title=Enhanced Oil Recovery |url=https://www.energy.gov/fecm/enhanced-oil-recovery |access-date=August 9, 2024}}</ref> Subsequently, natural gas companies in Texas began capturing the CO<sub>2</sub> produced by their processing plants and selling it to local oil producers for EOR.<ref name=":44" />{{Rp|page=25}}

The use of CCS as a means of reducing [[Human impact on the environment|human-caused]] CO<sub>2</sub> emissions is more recent. In 1977, the Italian physicist [[Cesare Marchetti]] proposed that CCS could be used to reduce emissions from [[Coal-fired power station|coal power plants]] and fuel refineries.<ref name="auto1">{{cite journal |last1=Ma |first1=Jinfeng |last2=Li |first2=Lin |last3=Wang |first3=Haofan |last4=Du |first4=Yi |last5=Ma |first5=Junjie |last6=Zhang |first6=Xiaoli |last7=Wang |first7=Zhenliang |date=July 2022 |title=Carbon Capture and Storage: History and the Road Ahead |journal=Engineering |volume=14 |pages=33–43 |bibcode=2022Engin..14...33M |doi=10.1016/j.eng.2021.11.024 |s2cid=247416947}}</ref><ref>{{cite journal | url=https://link.springer.com/article/10.1007/BF00162777 | doi=10.1007/BF00162777 | title=On geoengineering and the CO<sub>2</sub> problem | date=1977 | last1=Marchetti | first1=Cesare | journal=Climatic Change | volume=1 | issue=1 | pages=59–68 | bibcode=1977ClCh....1...59M }}</ref> Small-scale implementations were first demonstrated in the early 1980s and an economic evaluation was published in 1991.<ref name= "rochelle"/><ref>{{cite journal |last1=Booras |first1=G.S. |last2=Smelser |first2=S.C. |title=An engineering and economic evaluation of CO2 removal from fossil-fuel-fired power plants |journal=Energy |date=November 1991 |volume=16 |issue=11–12 |pages=1295–1305 |doi=10.1016/0360-5442(91)90003-5}}</ref> The first large-scale CO<sub>2</sub> capture and injection project with dedicated CO<sub>2</sub> storage and monitoring was commissioned at the [[Sleipner gas field]] in Norway in 1996.<ref name=":44" />{{Rp|page=25}}

In 2005, the IPCC released a report highlighting CCS,<ref name=":18" /> leading to increased government support for CCS in several countries.<ref name=":06">{{Cite journal |last1=Wang |first1=Nan |last2=Akimoto |first2=Keigo |last3=Nemet |first3=Gregory F. |date=2021-11-01 |title=What went wrong? Learning from three decades of carbon capture, utilization and sequestration (CCUS) pilot and demonstration projects |url=https://www.sciencedirect.com/science/article/pii/S030142152100416X |journal=Energy Policy |volume=158 |pages=112546 |doi=10.1016/j.enpol.2021.112546 |bibcode=2021EnPol.15812546W |issn=0301-4215 |access-date=2024-06-24|url-access=subscription }}</ref> Governments spent an estimated USD $30 billion on subsidies for CCS and for fossil-fuel-based hydrogen.<ref>{{Cite news |last=Lakhani |first=Nina |date=2024-08-29 |title=US leads wealthy countries spending billions of public money on unproven 'climate solutions' |url=https://www.theguardian.com/business/article/2024/aug/29/unproven-climate-solutions-spending |access-date=2024-09-18 |work=The Guardian |language=en-GB |issn=0261-3077}}</ref> Globally, 149 projects to store 130 million tonnes of CO<sub>2</sub> annually were proposed to be operational by 2020. Of these, around 70% were not implemented.<ref name=":13" /> Limited one-off capital grants, the absence of measures to address long-term liability for stored CO<sub>2</sub>, high operating costs, limited social acceptability and vulnerability of funding programmes to external budget pressures all contributed to project cancellations.<ref name=":12" />{{Rp|pages=|page=133}}

In 2020, the [[International Energy Agency]] (IEA) stated, “The story of CCUS has largely been one of unmet expectations: its potential to mitigate climate change has been recognised for decades, but deployment has been slow and so has had only a limited impact on global CO<sub>2</sub> emissions.”<ref name=":44" />{{Rp|page=18}}  

By July 2024, commercial-scale CCS was in operation at 44 plants worldwide.<ref name=":21">{{Cite web |title=Global Status Report 2024 |url=https://www.globalccsinstitute.com/resources/global-status-report/ |access-date=2024-10-19 |website=Global CCS Institute |pages=57–58 |language=en-AU}} The report lists 50 facilities, of which 3 are [[direct air capture]] facilities and 3 are transport/storage facilities</ref> Sixteen of these facilities were devoted to separating naturally-occurring CO<sub>2</sub> from raw natural gas. Seven facilities were for [[Hydrogen production|hydrogen]], [[Ammonia production|ammonia]], or [[fertilizer]] production, seven for chemical production, five for electricity and heat, and two for [[Oil refinery|oil refining]]. CCS was also used in one [[Steel mill|iron and steel plant]].<ref name=":21" />  Additionally, three facilities worldwide were devoted to CO<sub>2</sub> transport/storage.<ref name=":21" /> As of 2024, the [[oil and gas industry]] is involved in 90% of CCS capacity in operation around the world.<ref name=":28">{{Cite web |date=2023-11-23 |title=The Oil and Gas Industry in Net Zero Transitions – Analysis |url=https://www.iea.org/reports/the-oil-and-gas-industry-in-net-zero-transitions |access-date=2024-11-04 |website=IEA |language=en-GB}} Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref>{{Rp|page=15}} Collectively, the facilities capture about one-thousandth of global greenhouse gas emissions.<ref name=":2" />

Eighteen facilities were in the United States, fourteen in China, five in Canada, and two in Norway. Australia, Brazil, Qatar, Saudi Arabia, and the United Arab Emirates had one project each.<ref name=":21" />  As of 2020, North America has more than {{cvt|8000|km}} of CO<sub>2</sub> pipelines, and there are two CO<sub>2</sub> pipeline systems in Europe and two in the Middle East.<ref name=":44" />{{Rp|page=|pages=103–104}}

== Process overview ==
CCS facilities capture carbon dioxide before it enters the atmosphere. Generally, a [[chemical solvent]] or a porous solid material is used to separate the CO<sub>2</sub> from other components of a plant’s exhaust stream.<ref>{{Cite web |date=2023-12-13 |title=Carbon Capture and Storage in the United States |author=Congressional Budget Office |url=https://www.cbo.gov/publication/59832 |access-date=2024-09-18 |website=www.cbo.gov |language=en}}{{Source-attribution}}</ref> Most commonly, the gas stream passes through an [[Amine gas treating|amine solvent]], which binds the CO<sub>2</sub> molecule. This CO<sub>2</sub>-rich solvent is heated in a regeneration unit to release the CO<sub>2</sub> from the solvent. The CO<sub>2</sub> stream then undergoes conditioning to remove impurities and bring the gas to an appropriate temperature for compression.<ref>{{Cite journal |last1=Tamburini |first1=Federica |last2=Zanobetti |first2=Francesco |last3=Cipolletta |first3=Mariasole |last4=Bonvicini |first4=Sarah |last5=Cozzani |first5=Valerio |date=2024-11-01 |title=State of the art in the quantitative risk assessment of the CCS value chain |journal=Process Safety and Environmental Protection |volume=191 |pages=2044–2063 |doi=10.1016/j.psep.2024.09.066 |issn=0957-5820|doi-access=free |bibcode=2024PSEP..191.2044T }}</ref> The purified CO<sub>2</sub> stream is compressed and transported for storage or end-use and the released solvents are recycled to capture more CO<sub>2</sub> from the facility.<ref>{{Cite web |date=April 2023 |title=Pathways to Commercial Liftoff: Carbon Management |url=https://liftoff.energy.gov/carbon-management/ |access-date=2024-09-18 |website=United States Department of Energy |page=11 |language=en-US}}{{Source-attribution}}</ref>

After the {{CO2}} has been captured, it is usually compressed into a [[supercritical fluid]] and then injected underground. Pipelines are the cheapest way of transporting CO<sub>2</sub> in large quantities onshore and, depending on the distance and volumes, offshore.<ref name=":44" />{{Rp|page=|pages=103–104}} Transport via ship has been researched.  CO<sub>2</sub> can also be transported by truck or rail, albeit at higher cost per tonne of CO<sub>2</sub>.<ref name=":44" />{{Rp|page=|pages=103–104}}

== Technical components ==
{{See also|Carbon dioxide scrubber|Amine gas treating}}

CCS processes involve several different technologies working together. Technological components are used to separate and treat CO<sub>2</sub> from a  gas mixture, compress and transport the CO<sub>2</sub>, inject it into the subsurface, and monitor the overall process.  

There are three ways that CO<sub>2</sub>  can be separated from a gas mixture: post-combustion capture, pre-combustion capture, and oxy-combustion:<ref>{{cite journal |last1=Kanniche |first1=Mohamed |last2=Gros-Bonnivard |first2=René |last3=Jaud |first3=Philippe |last4=Valle-Marcos |first4=Jose |last5=Amann |first5=Jean-Marc |last6=Bouallou |first6=Chakib |title=Pre-combustion, post-combustion and oxy-combustion in thermal power plant for CO<sub>2</sub> capture |journal=Applied Thermal Engineering |date=January 2010 |volume=30 |issue=1 |pages=53–62 |doi=10.1016/j.applthermaleng.2009.05.005 |bibcode=2010AppTE..30...53K |url=https://hal.science/hal-00584285/file/PEER_stage2_10.1016%252Fj.applthermaleng.2009.05.005.pdf }}</ref>
*In ''[[post combustion capture]]'', the CO<sub>2</sub> is removed after combustion of the fossil fuel.
*The technology for ''pre-combustion'' is widely applied in natural gas processing.<ref name=":03" /> In these cases, the fossil fuel is partially [[redox|oxidized]], for instance in a [[gasification|gasifier]]. The [[Carbon monoxide|CO]] from the resulting [[syngas]] (CO and H<sub>2</sub>) reacts with added steam (H<sub>2</sub>O) and is [[Water gas shift reaction|shifted]] into CO<sub>2</sub> and H<sub>2</sub>. The resulting CO<sub>2</sub> can be captured from a relatively pure exhaust stream. The H<sub>2</sub> can be used as fuel. Several advantages and disadvantages apply versus post combustion capture.<ref name=":03" />
*In ''[[oxy-fuel combustion]]'' the fuel is burned in pure oxygen instead of air. The gas that is released consists of mostly CO<sub>2</sub> and water vapor. After water vapor is condensed through cooling, the result is an almost pure CO<sub>2</sub> stream. A disadvantage of this technique is that it requires a relatively large amount of oxygen, which is expensive and energy-intensive to produce.<ref name=":03" />

Absorption, or [[carbon dioxide scrubber|carbon scrubbing]] with [[amines]] is the dominant capture technology.<ref name=":44" />{{Rp|page=98}} Other technologies proposed for carbon capture are [[membrane gas separation]], [[chemical looping combustion]], [[calcium looping]], and use of [[Metal–organic framework|metal-organic frameworks]] and other [[Solid sorbents for carbon capture|solid sorbents]].<ref name="Bui 2018">{{cite journal |last1=Bui |first1=Mai |last2=Adjiman |first2=Claire S. |last3=Bardow |first3=André |last4=Anthony |first4=Edward J. |last5=Boston |first5=Andy |last6=Brown |first6=Solomon |last7=Fennell |first7=Paul S. |last8=Fuss |first8=Sabine |last9=Galindo |first9=Amparo |last10=Hackett |first10=Leigh A. |last11=Hallett |first11=Jason P. |last12=Herzog |first12=Howard J. |last13=Jackson |first13=George |last14=Kemper |first14=Jasmin |last15=Krevor |first15=Samuel |date=2018 |title=Carbon capture and storage (CCS): the way forward |journal=Energy & Environmental Science |volume=11 |issue=5 |pages=1062–1176 |doi=10.1039/C7EE02342A |doi-access=free |hdl-access=free |last16=Maitland |first16=Geoffrey C. |last17=Matuszewski |first17=Michael |last18=Metcalfe |first18=Ian S. |last19=Petit |first19=Camille |last20=Puxty |first20=Graeme |last21=Reimer |first21=Jeffrey |last22=Reiner |first22=David M. |last23=Rubin |first23=Edward S. |last24=Scott |first24=Stuart A. |last25=Shah |first25=Nilay |last26=Smit |first26=Berend |last27=Trusler |first27=J. P. Martin |last28=Webley |first28=Paul |last29=Wilcox |first29=Jennifer |last30=Mac Dowell |first30=Niall |bibcode=2018EnEnS..11.1062B |hdl=10044/1/55714}}</ref><ref>{{Cite journal |last1=Jensen |first1=Mark J. |last2=Russell |first2=Christopher S. |last3=Bergeson |first3=David |last4=Hoeger |first4=Christopher D. |last5=Frankman |first5=David J. |last6=Bence |first6=Christopher S. |last7=Baxter |first7=Larry L. |date=November 2015 |title=Prediction and validation of external cooling loop cryogenic carbon capture (CCC-ECL) for full-scale coal-fired power plant retrofit |journal=International Journal of Greenhouse Gas Control |language=en |volume=42 |pages=200–212 |bibcode=2015IJGGC..42..200J |doi=10.1016/j.ijggc.2015.04.009 |doi-access=free}}</ref><ref>{{cite tech report|last1=Baxter|first1=Larry L|last2=Baxter|first2=Andrew|last3=Bever|first3=Ethan|last4=Burt|first4=Stephanie|last5=Chamberlain|first5=Skyler|last6=Frankman|first6=David|last7=Hoeger|first7=Christopher|last8=Mansfield|first8=Eric|last9=Parkinson|first9=Dallin|last10=Sayre|first10=Aaron|last11=Stitt|first11=Kyler|title=Cryogenic Carbon Capture Development Final/Technical Report|date=28 September 2019|pages=DOE–SES–28697, 1572908|doi=10.2172/1572908|osti=1572908|s2cid=213628936}}</ref>

Impurities in CO<sub>2</sub> streams, like [[sulfur dioxide]]s and water vapor, can have a significant effect on their phase behavior and could cause increased pipeline and well corrosion. In instances where CO<sub>2</sub> impurities exist, a process is needed to remove them.<ref>{{Cite journal |last1=Sonke |first1=J. |last2=Morland |first2=B. H. |last3=Moulie |first3=G. |last4=Franke |first4=M. S. |date=2024-03-01 |title=Corrosion and chemical reactions in impure CO2 |url=https://linkinghub.elsevier.com/retrieve/pii/S1750583624000185 |journal=International Journal of Greenhouse Gas Control |volume=133 |pages=104075 |doi=10.1016/j.ijggc.2024.104075 |issn=1750-5836|url-access=subscription }}</ref>

== Storage and enhanced oil recovery ==
{{seealso|Enhanced oil recovery}}
[[File:CO2 geologic trapping mechanisms.jpg|thumb|Diagram of mechanisms for trapping carbon dioxide in dedicated geologic storage|alt=Four diagrams: 1) "Capturing" of CO2 at the surface connected by pipes to mid-ocean and then down to below the ocean and below a caprock. Below the caprock there is an area called "CO2 unsaturated brine", a layer called "Residually trapped CO2", and an area called "CO2 plume". The other three diagrams are labelled "Structural trap", "Residual trap", and "Solubility and mineral trap". See article text for descriptions of these concepts.]]
Storing CO<sub>2</sub> involves the injection of captured CO<sub>2</sub> into a deep underground geological reservoir of porous rock overlaid by an impermeable layer of rocks, which seals the reservoir and prevents the upward migration of CO<sub>2</sub> and escape into the atmosphere.<ref name=":44" />{{Rp|page=112}} The gas is usually compressed first into a supercritical fluid. When the compressed CO<sub>2</sub> is injected into a reservoir, it flows through it, filling the pore space. The reservoir must be at depths greater than {{cvt|800|m}} to retain the CO<sub>2</sub> in a fluid state.<ref name=":44" />{{Rp|page=112}}

As of 2024, around 80% of the CO<sub>2</sub> captured annually is used for enhanced oil recovery (EOR).<ref name=":13" />  In EOR, CO<sub>2</sub>  is injected into partially depleted [[oil fields]] to enhance production. The CO<sub>2</sub> binds with oil to make it less dense, allowing oil to rise to the surface faster. The addition of CO<sub>2</sub> also increases the overall reservoir pressure, thereby improving the mobility of the oil, resulting in a higher flow of oil towards the production wells.<ref name=":44"/>{{Rp|page=117}} Depending on the location, EOR results in around two additional barrels of oil for every tonne of CO<sub>2</sub> injected into the ground and using that oil produces approximately one tonne of CO<sub>2</sub>.<ref>{{Cite web |date=2019-04-11 |title=Can CO<sub>2</sub>-EOR really provide carbon-negative oil? – Analysis |url=https://www.iea.org/commentaries/can-co2-eor-really-provide-carbon-negative-oil |access-date=2024-10-11 |website=IEA |language=en-GB}}</ref> Oil extracted through EOR is mixed with CO<sub>2</sub>, which can then mostly be recaptured and re-injected multiple times. This CO<sub>2</sub> recycling process can reduce losses to 1%; however, it is energy-intensive.<ref name=":26">{{Cite web |date=2015-11-03 |title=Insights Series 2015 - Storing CO<sub>2</sub> through Enhanced Oil Recovery – Analysis |url=https://www.iea.org/reports/storing-co2-through-enhanced-oil-recovery |access-date=2024-10-25 |website=IEA |pages=29–33 |language=en-GB}}</ref> 

Around 20% of captured CO<sub>2</sub> is injected into dedicated geological storage,<ref name=":13" /> usually deep saline [[aquifer]]s. These are layers of porous and permeable rocks saturated with salty water.<ref name=":44" />{{Rp|page=112}} Worldwide, saline formations have higher potential storage capacity than depleted oil wells.<ref name="auto1"/> Dedicated geologic storage is generally less expensive than EOR because it does not require a high level of CO<sub>2</sub> purity and because suitable sites are more numerous, which means pipelines can be shorter.<ref name="auto1"/>

Various other types of reservoirs for storing captured CO<sub>2</sub> were being researched or piloted as of 2021: CO<sub>2</sub> could be injected into coal beds for [[enhanced coal bed methane recovery]].<ref name=":07">{{Cite journal |last1=Dziejarski |first1=Bartosz |last2=Krzyżyńska |first2=Renata |last3=Andersson |first3=Klas |date=June 2023 |title=Current status of carbon capture, utilization, and storage technologies in the global economy: A survey of technical assessment |journal=Fuel |volume=342 |pages=127776 |doi=10.1016/j.fuel.2023.127776 |bibcode=2023Fuel..34227776D |issn=0016-2361 |doi-access=free }}[[File:CC-BY_icon.svg|50x50px]] Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref>  ''Ex-situ mineral carbonation'' involves reacting CO<sub>2</sub> with [[Tailings|mine tailings]] or alkaline industrial waste to form stable minerals such as [[calcium carbonate]].<ref name=":5">{{Cite journal |last1=Snæbjörnsdóttir |first1=Sandra Ó |last2=Sigfússon |first2=Bergur |last3=Marieni |first3=Chiara |last4=Goldberg |first4=David |last5=Gislason |first5=Sigurður R. |last6=Oelkers |first6=Eric H. |date=February 2020 |title=Carbon dioxide storage through mineral carbonation |url=https://www.nature.com/articles/s43017-019-0011-8 |journal=Nature Reviews Earth & Environment |volume=1 |issue=2 |pages=90–102 |doi=10.1038/s43017-019-0011-8 |bibcode=2020NRvEE...1...90S |issn=2662-138X |access-date=2024-06-21}}</ref> ''In-situ mineral carbonation'' involves injecting CO<sub>2</sub> and water into underground formations that are rich in highly-reactive rocks such as [[basalt]]. There, the CO<sub>2</sub> may react with the rock to form stable carbonate minerals relatively quickly.<ref name=":5" /><ref>{{Cite journal |last1=Kim |first1=Kyuhyun |last2=Kim |first2=Donghyun |last3=Na |first3=Yoonsu |last4=Song |first4=Youngsoo |last5=Wang |first5=Jihoon |date=December 2023 |title=A review of carbon mineralization mechanism during geological CO<sub>2</sub> storage |journal=Heliyon |volume=9 |issue=12 |pages=e23135 |doi=10.1016/j.heliyon.2023.e23135 |doi-access=free |issn=2405-8440 |pmc=10750052 |pmid=38149201|bibcode=2023Heliy...923135K }}</ref> Once this process is complete, the risk of CO<sub>2</sub> escape from carbonate minerals is estimated to be close to zero.<ref name=":18">{{cite web |date=2005 |title=IPCC Special Report on Carbon Dioxide Capture and Storage |url=https://www.ipcc.ch/site/assets/uploads/2018/03/srccs_wholereport.pdf |access-date=16 August 2023 |publisher=Intergovernmental Panel on Climate Change; Cambridge University Press |editor-last1=Metz |editor-first1=Bert |editor-last2=Davidson |editor-first2=Ogunlade |editor-last3=De Conink |editor-first3=Heleen |editor-last4=Loos |editor-first4=Manuela |editor-last5=Meyer |editor-first5=Leo}}</ref>{{Rp|page=66}}

The global capacity for underground CO<sub>2</sub> storage is potentially very large and is unlikely to be a constraint on the development of CCS.<ref name=":44" />{{Rp|page=|pages=112–115}} Total storage capacity has been estimated at between 8,000 and 55,000 gigatonnes.<ref name=":44" />{{Rp|page=|pages=112–115}} However, a smaller fraction will most likely prove to be technically or commercially feasible.<ref name=":44" />{{Rp|page=|pages=112–115}} Global capacity estimates are uncertain, particularly for saline aquifers where more site characterization and exploration is still needed.<ref name=":44" />{{Rp|page=|pages=112–115}}

=== Long-term CO<sub>2</sub> leakage ===
{{See also|Monitoring of geological carbon dioxide storage}}

In geologic storage, the CO<sub>2</sub> is held within the reservoir through several [[Trapping mechanisms for carbon geosequestration|trapping mechanisms]]: ''structural'' trapping by an impermeable rock layer called a [[caprock]], ''solubility'' trapping in pore space water, ''residual'' trapping in individual or groups of pores, and ''mineral'' trapping by reacting with the reservoir rocks to form carbonate minerals.<ref name=":44" />{{Rp|page=112}} Mineral trapping progresses over time but is extremely slow.<ref>{{Cite book |last=Ringrose |first=Philip |title=How to Store CO<sub>2</sub> Underground: Insights from early-mover CCS Projects |publisher=Springer |year=2020 |isbn=978-3-030-33113-9 |location=Switzerland}}</ref>{{Rp|page=26}} 

After injection, supercritical CO<sub>2</sub> tends to rise until it is trapped beneath a caprock. Once it encounters a caprock, it spreads laterally until it encounters a gap. If there are [[fault (geology)|fault]] planes near the injection zone, CO<sub>2</sub> could migrate along the fault to the surface, leaking into the atmosphere, which would be potentially dangerous to life in the surrounding area. If the injection of CO<sub>2</sub> creates pressures underground that are too high, the formation will fracture, potentially causing an earthquake.<ref name=":25">Smit, Berend; Reimer, Jeffrey A.; Oldenburg, Curtis M.; Bourg, Ian C. (2014). ''Introduction to Carbon Capture and Sequestration''. London: Imperial College Press. {{ISBN|978-1-78326-328-8}}.</ref> While research suggests that earthquakes from injected CO<sub>2</sub> would be too small to endanger property, they could be large enough to cause a leak.<ref>{{Cite journal |last1=Zoback |first1=Mark D. |last2=Gorelick |first2=Steven M. |date=2012-06-26 |title=Earthquake triggering and large-scale geologic storage of carbon dioxide |journal=Proceedings of the National Academy of Sciences |language=en |volume=109 |issue=26 |pages=10164–10168 |doi=10.1073/pnas.1202473109 |doi-access=free |issn=0027-8424 |pmc=3387039 |pmid=22711814|bibcode=2012PNAS..10910164Z }}</ref> 

According to the IPCC, well-managed storage sites likely retain over 99% of injected CO₂ for more than a thousand years, where 'likely' means a 66–90% probability.<ref name=":18" />{{Rp|page=14,12}} Estimates of long-term leakage rates rely on complex simulations since field data is limited.<ref>{{Cite journal |last=Lenzen |first=Manfred |date=2011-12-15 |title=Global Warming Effect of Leakage From CO 2 Storage |url=http://www.tandfonline.com/doi/abs/10.1080/10643389.2010.497442 |journal=Critical Reviews in Environmental Science and Technology |language=en |volume=41 |issue=24 |pages=2169–2185 |doi=10.1080/10643389.2010.497442 |bibcode=2011CREST..41.2169L |issn=1064-3389|url-access=subscription }}</ref> If very large amounts of CO<sub>2</sub> are sequestered, even a 1% leakage rate over 1000 years could cause significant impact on the climate for future generations.<ref>{{Cite web |last1=Marshall |first1=Christa |last2=Climatewire |date=June 28, 2010 |title=Can Stored Carbon Dioxide Leak? |url=https://www.scientificamerican.com/article/can-stored-carbon-dioxide-leak/ |access-date=20 May 2022 |website=Scientific American |language=en}}</ref>

== Social and environmental impacts ==
=== Energy and water requirements ===
Facilities with CCS use more energy than those without CCS.<ref name=":29">{{Cite journal |last1=Zapp |first1=Petra |last2=Schreiber |first2=Andrea |last3=Marx |first3=Josefine |last4=Haines |first4=Mike |last5=Hake |first5=Jürgen-Friedrich |last6=Gale |first6=John |date=2012-05-01 |title=Overall environmental impacts of CCS technologies—A life cycle approach |url=https://linkinghub.elsevier.com/retrieve/pii/S175058361200028X |journal=International Journal of Greenhouse Gas Control |volume=8 |pages=12–21 |doi=10.1016/j.ijggc.2012.01.014 |bibcode=2012IJGGC...8...12Z |issn=1750-5836|url-access=subscription }}</ref> The energy consumed by CCS is called an "energy penalty".<ref name=":29" />  The energy penalty of CCS varies depending on the source of CO<sub>2</sub>. If the gas from the source has a very high concentration of CO<sub>2</sub>, additional energy is needed only to dehydrate, compress, and pump the CO<sub>2</sub>.<ref name=":44" />{{Rp|page=|pages=101–102}}   If the facility produces gas with a lower concentration of CO<sub>2</sub>, as is the case for power plants, energy is also required to separate CO<sub>2</sub> from other gas components.<ref name=":44" />{{Rp|page=|pages=101–102}} 

Early studies indicated that to produce the same amount of electricity, a coal power plant would need to burn 14–40% more coal and a [[Combined cycle power plant|natural gas combined cycle]] power plant would need to burn 11–22% more gas.<ref name=":18" />{{Rp|page=27}} When CCS is used in coal power plants, it has been estimated that about 60% of the energy penalty originates from the capture process, 30% comes from compression of the extracted CO<sub>2</sub>, and the remaining 10% comes from pumps and fans.<ref name="Rubin2012">{{cite journal |last1=Rubin |first1=Edward S. |last2=Mantripragada |first2=Hari |last3=Marks |first3=Aaron |last4=Versteeg |first4=Peter |last5=Kitchin |first5=John |date=October 2012 |title=The outlook for improved carbon capture technology |journal=Progress in Energy and Combustion Science |volume=38 |issue=5 |pages=630–671 |bibcode=2012PECS...38..630R |doi=10.1016/j.pecs.2012.03.003}}</ref>  

Depending on the technology used, CCS can require large amounts of water. For instance, coal-fired power plants with CCS may need to use 50% more water.<ref name=":0">{{Cite book |author=IPCC |author-link=IPCC |url=https://ipcc.ch/report/ar6/wg3/downloads/report/IPCC_AR6_WGIII_FullReport.pdf |title=Climate Change 2022: Mitigation of Climate Change |publisher=Cambridge University Press (In Press) |year=2022 |isbn=978-1-009-15792-6 |editor1-last=Shukla |editor1-first=P.R. |series=Contribution of Working Group III to the [[IPCC Sixth Assessment Report|Sixth Assessment Report]] of the Intergovernmental Panel on Climate Change |place=Cambridge, UK and New York, NY, USA |doi=10.1017/9781009157926 |ref={{harvid|IPCC AR6 WG3|2022}} |editor2-last=Skea |editor2-first=J. |editor3-last=Slade |editor3-first=R. |editor4-last=Al Khourdajie |editor4-first=A. |editor5-last=van Diemen |editor5-first=R. |editor6-last=McCollum |editor6-first=D. |editor7-last=Pathak |editor7-first=M. |editor8-last=Some |editor8-first=S. |editor9-last=Vyas |editor9-first=P. |display-editors=4 |editor10-first=R. |editor10-last=Fradera |editor11-first=M. |editor11-last=Belkacemi |editor12-first=A. |editor12-last=Hasija |editor13-first=G. |editor13-last=Lisboa |editor14-first=S. |editor14-last=Luz |editor15-first=J. |editor15-last=Malley}}</ref>{{Rp|page=668}}

=== Pollution ===
[[File:Pipeline_construction_in_Canada.jpg|thumb|The construction of pipelines adversely affects wildlife.<ref>{{Cite journal |last1=Richardson |first1=Matthew L. |last2=Wilson |first2=Benjamin A. |last3=Aiuto |first3=Daniel A. S. |last4=Crosby |first4=Jonquil E. |last5=Alonso |first5=Alfonso |last6=Dallmeier |first6=Francisco |last7=Golinski |first7=G. Karen |date=July 2017 |title=A review of the impact of pipelines and power lines on biodiversity and strategies for mitigation |url=http://link.springer.com/10.1007/s10531-017-1341-9 |journal=Biodiversity and Conservation |language=en |volume=26 |issue=8 |pages=1801–1815 |doi=10.1007/s10531-017-1341-9 |bibcode=2017BiCon..26.1801R |issn=0960-3115|url-access=subscription }}</ref> Pipeline construction is also associated with social harms to Indigenous communities.<ref name=":3">{{Cite web |last=Markusoff |first=Jason |date=2018-05-31 |title=Are 'man camps' that house pipeline construction workers a menace to Indigenous women? |url=https://macleans.ca/news/canada/are-man-camps-that-house-pipeline-construction-workers-a-menace-to-indigenous-women/ |access-date=2024-09-30 |work=Macleans.ca}}</ref>|left|alt=Photo of a forest with a pipeline and road running through it, and a piece of construction machinery on the road]]Since plants with CCS require more fuel to produce the same amount of electricity or heat,  the use of CCS increases the "upstream" environmental problems of fossil fuels. Upstream impacts include pollution caused by [[coal mining]], emissions from the fuel used to transport coal and gas, emissions from [[gas flaring]], and [[Fugitive emission|fugitive methane]] emissions. 

Since CCS facilities require more fossil fuel to be burned, CCS can cause a net increase in air pollution from those facilities. This can be mitigated by pollution control equipment, however no equipment can eliminate all pollutants.<ref name=":2">{{Cite web |last1=Lebling |first1=Katie |last2=Gangotra |first2=Ankita |last3=Hausker |first3=Karl |last4=Byrum |first4=Zachary |date=2023-11-13 |title=7 Things to Know About Carbon Capture, Utilization and Sequestration |url=https://www.wri.org/insights/carbon-capture-technology |publisher=[[World Resources Institute]] |language=en}}[[File:CC-BY_icon.svg|50x50px]] Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref> Since liquid amine solutions are used to capture CO<sub>2</sub> in many CCS systems, these types of chemicals can also be released as air pollutants if not adequately controlled. Among the chemicals of concern are volatile [[nitrosamines]] and [[Nitroamine|nitramines]] which are carcinogenic when inhaled or drunk in water.<ref>{{Cite journal |last1=Ravnum |first1=S. |last2=Rundén-Pran |first2=E. |last3=Fjellsbø |first3=L. M. |last4=Dusinska |first4=M. |date=July 2014 |title=Human health risk assessment of nitrosamines and nitramines for potential application in CO<sub>2</sub> capture |url=https://pubmed.ncbi.nlm.nih.gov/24747397 |journal=Regulatory Toxicology and Pharmacology |volume=69 |issue=2 |pages=250–255 |doi=10.1016/j.yrtph.2014.04.002 |issn=1096-0295 |pmid=24747397}}</ref>  

Studies that consider both upstream and downstream impacts indicate that adding CCS to power plants increases overall negative impacts on human health.<ref name=":19">{{Cite journal |last1=Mikunda |first1=Tom |last2=Brunner |first2=Logan |last3=Skylogianni |first3=Eirini |last4=Monteiro |first4=Juliana |last5=Rycroft |first5=Lydia |last6=Kemper |first6=Jasmin |date=2021-06-01 |title=Carbon capture and storage and the sustainable development goals |url=https://linkinghub.elsevier.com/retrieve/pii/S1750583621000700 |journal=International Journal of Greenhouse Gas Control |volume=108 |pages=103318 |doi=10.1016/j.ijggc.2021.103318 |bibcode=2021IJGGC.10803318M |issn=1750-5836|url-access=subscription }}</ref> The health impacts of adding CCS in the industrial sector are less well-understood.<ref name=":19" /> Health impacts vary significantly depending on the fuel used and the capture technology.<ref name=":19" />

After CO<sub>2</sub>  injected into underground geologic formations, there is a risk of nearby shallow [[groundwater]] becoming contaminated.<ref name=":18" />{{Rp|page=242}} Contamination can occur either from movement of the CO<sub>2</sub> into groundwater or from movement of displaced brine.<ref name=":18" />{{Rp|page=242}} Careful site selection and long-term monitoring are necessary to mitigate this risk.<ref name=":18" />{{Rp|page=239}}

=== Sudden CO<sub>2</sub> leakage ===
[[File:Main_symptoms_of_carbon_dioxide_toxicity.svg|thumb|Main symptoms of carbon dioxide toxicity|alt=Diagram of the upper human body with callouts naming the symptoms that affect different parts of the body.]]CO<sub>2</sub> is a colorless and odorless gas that accumulates near the ground because it is heavier than air. In humans, exposure to CO<sub>2</sub> at concentrations greater than 5% (50,000 [[parts-per notation|parts per million]]) causes the development of [[hypercapnia]] and [[respiratory acidosis]]. Concentrations of more than 10% may cause convulsions, coma, and death. CO<sub>2</sub> levels of more than 30% act rapidly leading to loss of consciousness in seconds.<ref>{{Cite journal |last1=Permentier |first1=Kris |last2=Vercammen |first2=Steven |last3=Soetaert |first3=Sylvia |last4=Schellemans |first4=Christian |date=2017-04-04 |title=Carbon dioxide poisoning: a literature review of an often forgotten cause of intoxication in the emergency department |journal=International Journal of Emergency Medicine |volume=10 |issue=1 |page=14 |doi=10.1186/s12245-017-0142-y |issn=1865-1372 |pmc=5380556 |pmid=28378268 |doi-access=free}}[[File:CC-BY_icon.svg|50x50px]] Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref>

Pipelines and storage sites can be sources of large accidental releases of CO<sub>2</sub> that can endanger local communities. A 2005 IPCC report stated that "existing CO<sub>2</sub> pipelines, mostly in areas of low population density, accident numbers reported per kilometre of pipeline are very low and are comparable to those for hydrocarbon pipelines."<ref name=":18" />{{Rp|page=12}} The report also stated that the local health and safety risks of geologic CO<sub>2</sub> storage were "comparable" to the risks of underground storage of natural gas if good site selection processes, regulatory oversight, monitoring, and incident remediation plans are in place.<ref name=":18" />{{Rp|page=12}} As of 2020, the ways that pipelines can fail is less well-understood for CO<sub>2</sub> pipelines than for natural gas or oil pipelines, and few safety standards exist that are specific to CO<sub>2</sub> pipelines.<ref>{{Cite journal |last1=Lu |first1=Hongfang |last2=Ma |first2=Xin |last3=Huang |first3=Kun |last4=Fu |first4=Lingdi |last5=Azimi |first5=Mohammadamin |date=2020-09-01 |title=Carbon dioxide transport via pipelines: A systematic review |url=https://linkinghub.elsevier.com/retrieve/pii/S0959652620320412 |journal=Journal of Cleaner Production |volume=266 |pages=121994 |doi=10.1016/j.jclepro.2020.121994 |bibcode=2020JCPro.26621994L |issn=0959-6526|url-access=subscription }}</ref>

While infrequent, accidents can be serious.  In 2020 a CO<sub>2</sub> pipeline ruptured following a mudslide near [[Satartia, Mississippi]], causing people nearby to lose consciousness.<ref>{{Cite web |last=Baurick |first=Tristan |date=2024-04-30 |title='A stark warning': Latest carbon dioxide leak raises concerns about safety, regulation |url=https://veritenews.org/2024/04/30/a-stark-warning-latest-carbon-dioxide-leak-raises-concerns-about-safety-regulation/ |access-date=2024-08-21 |website=Verite News |language=en-US}}</ref> About 200 people were evacuated and 45 were hospitalized, and some experienced longer-term effects on their health.<ref>{{cite news |author=Dan Zegart |date=August 26, 2021 |title=The Gassing Of Satartia |url=https://www.huffpost.com/entry/gassing-satartia-mississippi-co2-pipeline_n_60ddea9fe4b0ddef8b0ddc8f |access-date=Jan 8, 2025 |publisher=[[Huffington Post]]}}</ref><ref>{{cite news |author=Simon |first=Julia |date=May 10, 2023 |title=A rupture that hospitalized 45 people raised questions about CO<sub>2</sub> pipelines' safety |url=https://www.npr.org/2023/05/10/1175305683/a-rupture-that-hospitalized-45-people-raised-questions-about-co2-pipelines-safet |access-date=Jan 8, 2025 |publisher=[[NPR]]}}</ref> High concentrations of CO<sub>2</sub> in the air also caused vehicle engines to stop running, hampering the rescue effort.<ref>{{Cite news |last=Simon |first=Julia |date=September 25, 2023 |title=The U.S. is expanding CO<sub>2</sub> pipelines. One poisoned town wants you to know its story |url=https://www.npr.org/2023/05/21/1172679786/carbon-capture-carbon-dioxide-pipeline |access-date=Jan 8, 2025 |work=[[NPR]]}}</ref>

=== Jobs ===
{{See also|Just transition|}}

[[Retrofitting]] facilities with CCS can help to preserve jobs and economic prosperity in regions that rely on emissions-intensive industry, while avoiding the economic and social disruption of early retirements.<ref name=":44" />{{Rp|page=|pages=21–22}} For instance, Germany's plans to retire around 40 GW of coal-fired generation capacity before 2038 is accompanied by a EUR 40 billion (USD 45 billion) package to compensate the owners of coal mines and power plants as well as support the communities that will be affected.<ref name=":44" />{{Rp|page=|pages=21–22}} There is potential for reducing these costs if plants are retrofitted with CCS. Retrofitting CO<sub>2</sub> capture equipment can enable the continued operation of existing plants, as well as associated infrastructure and supply chains.<ref name=":44" />{{Rp|page=|pages=21–22}}

=== Equity ===
{{See also|Distributive justice|}}

In the United States, the types of facilities that could be retrofitted with CCS are often located in communities that have already borne the negative environmental and health impacts of living near power or industrial facilities.<ref name=":2" /> These facilities are disproportionately located in poor and/or minority communities.<ref>{{Cite web |last=White House Environmental Justice Advisory Council |date=2021 |title=Justice40 Climate and Economic Justice Screening Tool & Executive Order 12898 Revisions: Interim Final Recommendations |url=https://legacy-assets.eenews.net/open_files/assets/2021/05/17/document_ew_01.pdf}}</ref> While there is evidence that CCS can help reduce non-CO<sub>2</sub> pollutants along with capturing CO<sub>2</sub>, [[environmental justice]] groups are often concerned that CCS will be used as a way to prolong a facility’s lifetime and continue the local harms it causes.<ref name=":2" /> Often, community-based organizations would prefer that a facility be shut down and for investment be focused instead on cleaner production processes, such as renewable electricity.<ref name=":2" />

Construction of [[Pipelines in Canada|pipelines]] often involves setting up work camps in remote areas. In Canada and the United States, oil and gas pipeline construction in remote communities is associated with social harms including sexual violence,<ref name=":3" /> and this history has led some Indigenous communities to oppose construction of CO<sub>2</sub> pipelines.<ref>{{Cite news |last=Splitter |first=Jenny |date=2022-07-07 |title=The bitter fight to stop a 2,000-mile carbon pipeline |url=https://www.theguardian.com/environment/2022/jul/07/iowa-pipelines-farmers-indigenous-people-fight |access-date=2025-01-11 |work=The Guardian |language=en-GB |issn=0261-3077}}</ref>  

== Cost ==
Project cost, low technology readiness levels in capture technologies, and a lack of revenue streams are among the main reasons for CCS projects to stop.<ref name=":13" /> A commercial-scale project typically requires an upfront capital investment of up to several billion dollars.<ref name=":22">{{Cite journal |last1=Lipponen |first1=Juho |last2=McCulloch |first2=Samantha |last3=Keeling |first3=Simon |last4=Stanley |first4=Tristan |last5=Berghout |first5=Niels |last6=Berly |first6=Thomas |date=July 2017 |title=The Politics of Large-scale CCS Deployment |journal=Energy Procedia |language=en |volume=114 |pages=7581–7595 |doi=10.1016/j.egypro.2017.03.1890|doi-access=free |bibcode=2017EnPro.114.7581L }}</ref> According to the U.S. Environmental Protection Agency, CCS would increase the cost of electricity generation from coal plants by $7 to $12/[[MWh]].<ref>{{Cite web |last=Environmental Protection Agency |date=May 23, 2023 |title=New Source Performance Standards for Greenhouse Gas Emissions From New, Modified, and Reconstructed Fossil Fuel-Fired Electric Generating Units; Emission Guidelines for Greenhouse Gas Emissions From Existing Fossil Fuel-Fired Electric Generating Units; and Repeal of the Affordable Clean Energy Rule |url=https://www.federalregister.gov/documents/2023/05/23/2023-10141/new-source-performance-standards-for-greenhouse-gas-emissions-from-new-modified-and-reconstructed |access-date=September 20, 2023 |website=Federal Register |at=Page 333447}}</ref> 

The cost of CCS varies greatly by CO<sub>2</sub> source. If the facility produces a gas mixture with a high concentration of CO<sub>2</sub>, as is the case for natural gas processing, it can be captured and compressed for USD 15–25/tonne.<ref name=":8" /> Power plants, cement plants, and iron and steel plants produce more dilute gas streams, for which the cost of capture and compression is USD 40–120/tonne CO<sub>2</sub>.<ref name=":8">{{Cite web |date=2021-02-17 |title=Is carbon capture too expensive? – Analysis |url=https://www.iea.org/commentaries/is-carbon-capture-too-expensive |access-date=2024-09-11 |website=IEA . Text was copied from this source, which is under a CC-BY licence. |language=en-GB}}</ref>  In the United States, the cost of onshore pipeline transport is in the range of USD 2–14/tonne CO<sub>2</sub>, and more than half of onshore storage capacity is estimated to be available below USD 10/tonne CO<sub>2</sub>.<ref name=":8" /> CCS implementations involve multiple technologies that are highly customized to each site, which limits the industry's ability to reduce costs through [[Learning-by-doing (economics)|learning-by-doing]].<ref>{{Cite news |last=Stapczynski |first=Stephen |date=September 13, 2023 |title=Big Oil's Climate Fix Is Running Out of Time to Prove Itself |url=https://www.bloomberg.com/features/2023-carbon-capture-technology-running-out-of-time/ |access-date=2024-10-02 |work=Bloomberg |language=en}}</ref>

== Role in climate change mitigation ==

=== Comparison with other mitigation options ===
Compared to other options for reducing emissions, CCS is very expensive. For instance, removing CO<sub>2</sub> in fossil fuel power plants increases costs by USD $50–$200 per tonne of CO<sub>2</sub> removed.<ref name=":0"/>{{Rp|page=38}} There are many ways to reduce emissions that cost less than USD $20 per tonne of avoided CO<sub>2</sub> emissions.<ref>{{Cite journal |last1=Schumer |first1=Clea |last2=Boehm |first2=Sophie |last3=Fransen |first3=Taryn |last4=Hausker |first4=Karl |last5=Dellesky |first5=Carrie |date=2022-04-04 |title=6 Takeaways from the 2022 IPCC Climate Change Mitigation Report |url=https://www.wri.org/insights/ipcc-report-2022-mitigation-climate-change |journal=World Resources Institute |language=en}}</ref> Options that have far more potential to reduce emissions at lower cost than CCS include [[Public transport|public transit]], [[Electric vehicle|electric vehicles]], and various energy efficiency measures.<ref name=":0"/>{{Rp|page=38}}  Wind and solar power are often the lowest-cost ways to produce electricity, even when compared to power plants that do ''not'' use CCS.<ref name=":0" />{{Rp|page=38}} The dramatic fall in the costs of renewable power and batteries has made it difficult for fossil fuel plants with CCS to be cost-competitive.<ref name=":8" />

=== Priority uses ===
[[File:Heidelberg Brevik Carbon Capture.jpg|thumb|The Heidelberg Brevik Carbon Capture facility, scheduled to start operating in 2025, will be the first commercial-scale use of CCS in cement production.<ref>{{Cite news |last=Niranjan |first=Ajit |date=2024-08-12 |title='We're still in the 1970s with cement': Norway plant to blaze carbon-free concrete trail |url=https://www.theguardian.com/environment/article/2024/aug/12/were-still-in-the-1970s-with-cement-norway-plant-to-blaze-carbon-free-concrete-trail |access-date=2025-01-20 |work=The Guardian |language=en-GB |issn=0261-3077}}</ref>|alt=Photo of the exterior of a cement plant]]
[[File:Percentage change wind and solar versus carbon capture and storage.png|thumb|Compared to solar and wind power, CCS has seen relatively flat growth in installed capacity since 2010.|alt=Chart showing the percentage change in global wind and storage power generation from 2010 to 2023, and the same for carbon capture and storage capacity from 2010 to 2023]]
In the literature on [[climate change mitigation]], CCS is described as having a small but critical role in reducing greenhouse gas emissions.<ref name=":2" /><ref name=":0" />{{Rp|page=28}} The IPCC estimated in 2014 that forgoing CCS altogether would make it 138% more expensive to keep global warming within 2 degrees Celsius.<ref>{{Cite book |author=IPCC |author-link=IPCC |title={{Harvnb|IPCC AR5 WG3 |2014}} |year=2014 |page=15 |chapter=Summary for Policymakers |ref={{harvid|IPCC AR5 WG3 Summary for Policymakers|2014}}<!-- ipcc:20200216 --> |chapter-url=https://archive.ipcc.ch/pdf/assessment-report/ar5/wg3/ipcc_wg3_ar5_summary-for-policymakers.pdf}}</ref> Excessive reliance on CCS as a mitigation tool would also be costly and technically unfeasible. According to the IEA, attempting to abate oil and gas consumption only through CCS and direct air capture would cost USD 3.5 trillion per year, which is about the same as the annual revenue of the entire oil and gas industry.<ref name=":4">{{Cite web |title=Executive summary – The Oil and Gas Industry in Net Zero Transitions – Analysis |url=https://www.iea.org/reports/the-oil-and-gas-industry-in-net-zero-transitions/executive-summary |access-date=2024-09-19 |website=IEA |language=en-GB}}Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref> Emissions are relatively difficult or expensive to abate without CCS in the following niches:<ref name=":44" />{{Rp|page=|pages=13–14}}

* '''Heavy Industry:''' CCS is one of the few available technologies that can significantly reduce emissions associated with the production of cement, chemicals, and steel.<ref name=":44" />{{Rp|page=|pages=21–24}} A portion of the CO<sub>2</sub> emissions from these processes come from chemical reactions, in addition to emissions from burning fuels for heat. For example, approximately one third of emissions from cement making arise from burning fuels and two thirds arise from the chemical process.<ref>{{Cite web |last1=Lehne |first1=Johanna |last2=Preston |first2=Felix |date=13 June 2018 |title=Making Concrete Change: Innovation in Low-carbon Cement and Concrete |url=https://www.chathamhouse.org/sites/default/files/publications/research/2018-06-13-making-concrete-change-cement-lehne-preston.pdf |access-date=28 November 2024 |website=Chatham House}}</ref>  The Global Cement and Concrete Association say that CCS could reduce carbon emissions by 36%.<ref>{{Cite web |title=4 ways to make the cement industry more sustainable |url=https://www.weforum.org/stories/2024/09/cement-production-sustainable-concrete-co2-emissions/ |archive-url=http://web.archive.org/web/20250105131752/https://www.weforum.org/stories/2024/09/cement-production-sustainable-concrete-co2-emissions/ |archive-date=2025-01-05 |access-date=2025-01-12 |website=World Economic Forum |language=en}}</ref> Cleaner industrial processes are at varying stages of development and some have been commercialized,<ref>{{Cite journal |last1=Gailani |first1=Ahmed |last2=Cooper |first2=Sam |last3=Allen |first3=Stephen |last4=Pimm |first4=Andrew |last5=Taylor |first5=Peter |last6=Gross |first6=Robert |date=2024-03-20 |title=Assessing the potential of decarbonization options for industrial sectors |journal=Joule |volume=8 |issue=3 |pages=576–603 |doi=10.1016/j.joule.2024.01.007 |issn=2542-4351|doi-access=free |bibcode=2024Joule...8..576G }}</ref> but are far from being widely-deployed.<ref name=":0" />{{Rp|page=29}}
* '''Retrofits:''' CCS can be retrofitted to existing coal and natural gas power plants and industrial facilities to enable the continued operation of existing plants while reducing their emissions.<ref name=":44" />{{Rp|page=|pages=21–24}}
* '''Natural gas processing:''' CCUS is the only solution to reduce the CO<sub>2</sub> emissions from [[natural gas processing]].<ref name=":44" />{{Rp|page=|pages=21–24}} This does not reduce the emissions released when the gas is burned.<ref name=":2" />
* '''Hydrogen:  '''Nearly all [[Hydrogen economy|hydrogen]] today is produced from natural gas or coal. Facilities can incorporate CCS to capture the CO<sub>2</sub> released in these processes.<ref name=":44" />{{Rp|page=|pages=21–24}}   
* '''Complement to renewable electricity:''' In the IEA's scenario for net zero emissions, 251 GW of electricity worldwide are produced by coal and gas plants equipped with CCS by 2050, while 54,679 GW of electricity are produced by [[Solar power|solar PV]] and [[Wind power|wind]].<ref name=":12">{{Cite web |date=2023-09-26 |title=Net Zero Roadmap: A Global Pathway to Keep the 1.5 °C Goal in Reach – Analysis |url=https://www.iea.org/reports/net-zero-roadmap-a-global-pathway-to-keep-the-15-0c-goal-in-reach |access-date=2024-09-11 |website=IEA |language=en-GB}}</ref>{{Rp|pages=91–92}} Although solar and wind energy are typically cheaper, power plants that burn natural gas, biomass, or coal have the advantage of being able to produce electricity in any season and any time of day, and can be [[Dispatchable generation|dispatched]] at times of high demand.<ref name=":44" />{{Rp|page=|pages=51–52}} A small amount of power plant capacity can help to meet the growing need for system flexibility as the share of wind and solar increases.<ref name=":44" />{{Rp|page=|pages=51–52}}  The potential for a robust power grid using [[100% renewable energy]] has been modelled as a feasible option for many regions, which would make fossil CCS in the electricity sector unnecessary.<ref>{{Cite journal |last1=Breyer |first1=Christian |last2=Khalili |first2=Siavash |last3=Bogdanov |first3=Dmitrii |last4=Ram |first4=Manish |last5=Oyewo |first5=Ayobami Solomon |last6=Aghahosseini |first6=Arman |last7=Gulagi |first7=Ashish |last8=Solomon |first8=A. A. |last9=Keiner |first9=Dominik |last10=Lopez |first10=Gabriel |last11=Østergaard |first11=Poul Alberg |last12=Lund |first12=Henrik |last13=Mathiesen |first13=Brian V. |last14=Jacobson |first14=Mark Z. |last15=Victoria |first15=Marta |date=2022 |title=On the History and Future of 100% Renewable Energy Systems Research |url=https://ieeexplore.ieee.org/document/9837910 |journal=IEEE Access |volume=10 |pages=78176–78218 |bibcode=2022IEEEA..1078176B |doi=10.1109/ACCESS.2022.3193402 |issn=2169-3536}}</ref>  However, this approach may be more expensive.<ref name=":0" />{{Rp|page=676}}
* '''Bioenergy with carbon capture and storage:''' [[Bioenergy with carbon capture and storage]] (BECCS) is the process of extracting [[bioenergy]] from [[Biomass (energy)|biomass]] and capturing and storing the CO<sub>2</sub>  that is produced. Under some conditions, BECCS can [[Carbon dioxide removal|remove carbon dioxide]] from the atmosphere.<ref name=":34">{{Cite book |last=National Academies of Sciences |first=Engineering |url=https://www.nap.edu/catalog/25259/negative-emissions-technologies-and-reliable-sequestration-a-research-agenda |title=Negative Emissions Technologies and Reliable Sequestration: A Research Agenda |date=2018-10-24 |isbn=978-0-309-48452-7 |pages=10–13 |language=en |doi=10.17226/25259 |pmid=31120708 |access-date=2020-02-22 |archive-url=https://web.archive.org/web/20200525204549/https://www.nap.edu/catalog/25259/negative-emissions-technologies-and-reliable-sequestration-a-research-agenda |archive-date=2020-05-25 |url-status=live |s2cid=134196575}}</ref>
The IPCC stated in 2022 that “implementation of CCS currently faces technological, economic, institutional, ecological-environmental and socio-cultural barriers.”<ref name=":0" />{{Rp|page=28}}  Since CCS can only be used with large, stationary emission sources, it cannot reduce the emissions from burning fossil fuels in vehicles and homes. The IEA describes "excessive expectations and reliance" on CCS and direct air capture as a common misconception.<ref name=":4" /> To reach targets set in the [[Paris Agreement]], CCS must be accompanied by a steep decline in the production and use of fossil fuels.<ref name=":2" /><ref name=":0" />{{Rp|page=672}}

=== Effectiveness in reducing greenhouse gas emissions ===
[[File:Mina de carbón en Estercuel (Aragón).jpg|thumb|left|Coal  plants with CCS usually burn more coal to provide the energy needed for CCS processes. This increases the [[environmental effects of coal mining]].|alt=Photo of a person looking at a large open area in which coal mining has taken place]]

When CCS is used for electricity generation, most studies assume that 85-90% of the CO<sub>2</sub> in the exhaust stream is captured.<ref>{{Cite journal |last1=Budinis |first1=Sara |last2=Krevor |first2=Samuel |last3=Dowell |first3=Niall Mac |last4=Brandon |first4=Nigel |last5=Hawkes |first5=Adam |date=2018-11-01 |title=An assessment of CCS costs, barriers and potential |journal=Energy Strategy Reviews |volume=22 |pages=61–81 |bibcode=2018EneSR..22...61B |doi=10.1016/j.esr.2018.08.003 |issn=2211-467X |doi-access=free}}</ref> However, industry representatives say actual capture rates are closer to 75%, and have lobbied for government programs to accept this lower target.<ref>{{Cite web |last=Westervelt |first=Amy |date=2024-07-29 |title=Oil companies sold the public on a fake climate solution — and swindled taxpayers out of billions |url=https://www.vox.com/climate/363076/climate-change-solution-shell-exxon-mobil-carbon-capture |access-date=2024-09-11 |website=Vox |language=en-US}}</ref>  The potential for a CCS project to reduce emissions depends on several factors in addition to the capture rate. These factors include the amount of additional energy needed to power CCS processes, the source of the additional energy used, and post-capture leakage. The energy needed for CCS usually comes from fossil fuels whose mining, processing, and transport produce emissions.  Some studies indicate that under certain circumstances the overall emissions reduction from CCS can be very low, or that adding CCS can even increase emissions relative to no capture.<ref>{{Cite journal |last1=Rojas-Rueda |first1=David |last2=McAuliffe |first2=Kelly |last3=Morales-Zamora |first3=Emily |date=2024-06-01 |title=Addressing Health Equity in the Context of Carbon Capture, Utilization, and Sequestration Technologies |url=https://link.springer.com/article/10.1007/s40572-024-00447-6 |journal=Current Environmental Health Reports |language=en |volume=11 |issue=2 |pages=225–237 |doi=10.1007/s40572-024-00447-6 |pmid=38600409 |bibcode=2024CEHR...11..225R |issn=2196-5412|url-access=subscription }}</ref><ref>{{cite journal |last1=Farajzadeh |first1=R. |last2=Eftekhari |first2=A.A. |last3=Dafnomilis |first3=G. |last4=Lake |first4=L.W. |last5=Bruining |first5=J. |date=March 2020 |title=On the sustainability of CO<sub>2</sub> storage through CO<sub>2</sub>-Enhanced oil recovery |journal=Applied Energy |volume=261 |pages=114467 |doi=10.1016/j.apenergy.2019.114467|doi-access=free |bibcode=2020ApEn..26114467F }}</ref> For instance, one study found that in the [[Petra Nova]] CCS retrofit of a coal power plant, the actual rate of emissions reduction was so low that it would average only 10.8% over a 20-year time frame.<ref>{{Cite journal |last=Jacobson |first=Mark Z. |date=2019 |title=The health and climate impacts of carbon capture and direct air capture |url=https://xlink.rsc.org/?DOI=C9EE02709B |journal=Energy & Environmental Science |language=en |volume=12 |issue=12 |pages=3567–3574 |doi=10.1039/C9EE02709B |bibcode=2019EnEnS..12.3567J |issn=1754-5692|url-access=subscription }}</ref> 

Some CCS implementations have not sequestered carbon at their designed capacity, either for business or technical reasons.<ref name=":14" /><ref name=":2" /> For instance, in the [[List of carbon capture and storage projects#Shute Creek Gas Processing Facility|Shute Creek Gas Processing Facility]], around half of the CO<sub>2</sub> that has been captured has been sold for [[Enhanced oil recovery|EOR]], and the other half vented to the atmosphere because it could not be profitably sold.<ref name=":54">{{Cite web |last1=Robertson |first1=Bruce |last2=Mousavian |first2=Milad |date=September 2022 |title=The Carbon Capture Crux: Lessons Learned |url=https://ieefa.org/resources/carbon-capture-crux-lessons-learned |access-date=2022-10-01 |website=Institute for Energy Economics and Financial Analysis |language=en}}</ref>{{Rp|page=19}} In one year of operation of the [[Gorgon gas project]] in Australia, issues with subsurface water prevented two-thirds of captured CO<sub>2</sub> from being injected.<ref>{{Cite web |last1=Smyth |first1=Jamie |last2=McCormick |first2=Myles |date=November 16, 2023 |title=Chevron plots carbon storage future despite Australia plant setbacks |url=https://www.ft.com/content/82b4faf6-2915-4979-aa7c-4930eaa459b9 |access-date=2024-10-19 |website=Financial Times}}</ref>  A 2022 analysis of 13 major CCS projects found that most had either sequestered far less CO<sub>2</sub> than originally expected, or had failed entirely.<ref name=":14">{{Cite web |last=Vaughan |first=Adam |date=1 September 2022 |title=Most major carbon capture and storage projects haven't met targets |url=https://www.newscientist.com/article/2336018-most-major-carbon-capture-and-storage-projects-havent-met-targets/ |access-date=2024-08-28 |website=[[New Scientist]] |language=en-US}}</ref><ref name=":54" />

==== Emissions with enhanced oil recovery ====
<!-- This section is used as an [[Template:Excerpt|excerpt]] in [[Enhanced oil recovery]] -->There is controversy over whether carbon capture followed by enhanced oil recovery is beneficial for the climate. The EOR process is energy-intensive because of the need to separate and re-inject CO<sub>2</sub> multiple times to minimize losses. If CO<sub>2</sub> losses are kept at 1%, the energy required for EOR operations results in around 0.23 tonnes of CO<sub>2</sub> emissions per tonne of CO<sub>2</sub> sequestered.<ref name=":26" />

Furthermore, when the oil that is extracted using EOR is subsequently burned, CO<sub>2</sub> is released. If these emissions are included in calculations, carbon capture with EOR is usually found to ''increase'' overall emissions compared to not using carbon capture at all.<ref name=":113" /> If the emissions from burning extracted oil are excluded from calculations, carbon capture with EOR is found to ''decrease'' emissions. In arguments for excluding these emissions, it is assumed that oil produced by EOR displaces conventionally-produced oil instead of adding to the global consumption of oil.<ref name=":113" /> A 2020 review found that scientific papers were roughly evenly split on the question of whether carbon capture with EOR increased or decreased emissions.<ref name=":113" />

The International Energy Agency's model of oil supply and demand indicates that 80% of oil produced in EOR will displace other oil on the market.<ref name=":26" /> Using this model, it estimated that for each tonne of CO<sub>2</sub> sequestered, burning the oil produced by conventional EOR leads to 0.13 tonnes of CO<sub>2</sub> emissions (in addition to the 0.24 tonnes of CO<sub>2</sub> emitted during the EOR process itself).<ref name=":26" />   

=== Pace of implementation ===
As of 2023 CCS captures around 0.1% of global emissions — around 45 million tonnes of CO<sub>2</sub>.<ref name=":2" /> Climate models from the IPCC and the IEA show it capturing around 1 billion tonnes of CO<sub>2</sub> by 2030 and several billions of tons by 2050.<ref name=":2" /> Technologies for CCS in high-priority niches, such as cement production, are still immature. The IEA notes "a disconnect between the level of maturity of individual CO<sub>2</sub> capture technologies and the areas in which they are most needed."<ref name=":44" />{{Rp|page=92}}

CCS implementations involve long approval and construction times and the overall pace of implementation has historically been slow.<ref name=":20">{{Cite web |title=Carbon Capture, Utilisation and Storage - Energy System |url=https://www.iea.org/energy-system/carbon-capture-utilisation-and-storage#tracking |access-date=2024-08-30 |website=IEA |language=en-GB}}</ref> As a result of the lack of progress, authors of climate change mitigation strategies have repeatedly reduced the role of CCS.<ref>{{Cite web |date=2023-09-26 |title=Net Zero Roadmap: A Global Pathway to Keep the 1.5 °C Goal in Reach – Analysis |url=https://www.iea.org/reports/net-zero-roadmap-a-global-pathway-to-keep-the-15-0c-goal-in-reach |access-date=2024-09-24 |website=IEA |language=en-GB}}</ref>{{Rp|page=132}}  Some observers such as the IEA call for increased commitment to CCS in order to meet targets.<ref name=":20" />{{Rp|page=16}} Other observers see the slow pace of implementation as an indication that the concept of CCS is fundamentally unlikely to succeed, and call for efforts to be redirected to other mitigation tools such as renewable energy.<ref>{{Cite web |last=Oglesby |first=Cameron |date=2023-10-20 |title=What's the deal with carbon capture and storage? » Yale Climate Connections |url=https://yaleclimateconnections.org/2023/10/whats-the-deal-with-carbon-capture-and-storage/ |access-date=2024-09-28 |website=Yale Climate Connections |language=en-US}}</ref>
== Political debate ==
[[File:Crowd Checks Out Clean Coal at Missouri State Fair (6072555381).jpg|thumb|An information truck on "clean coal" from the [[American Coalition for Clean Coal Electricity]], an advocacy group representing coal producers, utility companies and railroads.<ref>{{Cite web| last = Samuelsohn| first = Darren| title = 'Clean coal' group downsizing amid industry struggles| work = POLITICO| access-date = 2024-09-29| date = 2015-09-28| url = https://www.politico.com/story/2015/09/american-coalition-for-clean-coal-electricity-cuts-staff-214149}}</ref>|alt=Photo of a crowd lining up outside a truck. The truck has "Clean coal technology. It works." painted on the side. ]]
[[File:Protest Against Carbon Capture and Storage (51697298019).jpg|thumb|Protest against CCS in 2021 in [[Torquay]], England|alt=Cloth banner being held up by two people. The banner has a picture of a tree with an arrow pointing to it saying "Carbon capture storage". The banner also has a picture of an industrial facility and an arrow pointing to it saying "Another big lie".]]
CCS has been discussed by political actors at least since the start of the [[UNFCCC]]<ref>{{cite journal |last1=Carton |first1=Wim |last2=Asiyanbi |first2=Adeniyi |last3=Beck |first3=Silke |last4=Buck |first4=Holly J. |last5=Lund |first5=Jens F. |title=Negative emissions and the long history of carbon removal |journal=WIREs Climate Change |date=November 2020 |volume=11 |issue=6 |doi=10.1002/wcc.671 |bibcode=2020WIRCC..11E.671C |doi-access=free }}</ref> negotiations in the beginning of the 1990s, and remains a very divisive issue.<ref name=":10">{{Cite web |last=Westervelt |first=Amy |date=2024-07-29 |title=Oil companies sold the public on a fake climate solution — and swindled taxpayers out of billions |url=https://www.vox.com/climate/363076/climate-change-solution-shell-exxon-mobil-carbon-capture |access-date=2024-07-30 |website=Vox |language=en-US}}</ref> 

Fossil fuel companies have heavily promoted CCS, framing it as an area of innovation and cost-effectiveness.<ref name=":27">{{Cite journal |last1=Gunderson |first1=Ryan |last2=Stuart |first2=Diana |last3=Petersen |first3=Brian |date=2020-04-10 |title=The fossil fuel industry's framing of carbon capture and storage: Faith in innovation, value instrumentalization, and status quo maintenance |url=https://linkinghub.elsevier.com/retrieve/pii/S0959652619346372 |journal=Journal of Cleaner Production |volume=252 |pages=119767 |doi=10.1016/j.jclepro.2019.119767 |bibcode=2020JCPro.25219767G |issn=0959-6526|url-access=subscription }}</ref> Public statements from fossil fuel companies and fossil-based electric utilities ask for “recognition” that fossil fuel usage will increase in the future and suggest that CCS will allow the fossil fuel era to be extended.<ref name=":27" />  Their statements typically position CCS as a necessary way to tackle climate change, while not mentioning options for reducing fossil fuel use.<ref name=":27" /> According to the International Energy Agency, as of 2023, annual investments in the oil and gas sector are double the amount needed to produce the amount of fuel that would be compatible with limiting global warming to 1.5°C.<ref name=":28" />{{Rp|page=14}} 

Fossil fuel industry representatives have had a strong presence at UN climate conferences.<ref name=":7">{{Cite web |last=Dinan |first=Will |date=2024-02-13 |title=Oil and gas lobbyists have deep pockets and access to politicians, but an EU ban could be in the pipeline |url=https://theconversation.com/oil-and-gas-lobbyists-have-deep-pockets-and-access-to-politicians-but-an-eu-ban-could-be-in-the-pipeline-223388 |access-date=2024-10-02 |website=The Conversation |language=en-US}}</ref> In these conferences, they have advocated for agreements to use language about reducing the emissions from fossil fuel use (through CCS), instead of language about reducing the use of fossil fuels.<ref name=":7" /> In the [[2023 United Nations Climate Change Conference]], at least 475 lobbyists for CCS were granted access.<ref>{{Cite news |last=Lakhani |first=Nina |date=2023-12-08 |title=At least 475 carbon-capture lobbyists attending Cop28 |url=https://www.theguardian.com/environment/2023/dec/08/at-least-475-carbon-capture-lobbyists-attending-cop28 |access-date=2024-10-02 |work=The Guardian |language=en-GB |issn=0261-3077}}</ref>    

Many environmental NGOs such as [[Friends of the Earth]] hold strongly negative views on CCS.<ref>{{Cite journal |last1=Hansson |first1=Anders |last2=Anshelm |first2=Jonas |last3=Fridahl |first3=Mathias |last4=Haikola |first4=Simon |date=2022-08-01 |title=The underworld of tomorrow? How subsurface carbon dioxide storage leaked out of the public debate |url=https://linkinghub.elsevier.com/retrieve/pii/S2214629622001104 |journal=Energy Research & Social Science |volume=90 |pages=102606 |doi=10.1016/j.erss.2022.102606 |bibcode=2022ERSS...9002606H |issn=2214-6296}}</ref>  In surveys, environmental NGOs'  importance ratings for fossil energy with CCS have been around as low as their ratings for nuclear energy.<ref name=":63">{{Cite journal |last1=Romanak |first1=Katherine |last2=Fridahl |first2=Mathias |last3=Dixon |first3=Tim |date=January 2021 |title=Attitudes on Carbon Capture and Storage (CCS) as a Mitigation Technology within the UNFCCC |journal=Energies |language=en |volume=14 |issue=3 |pages=629 |doi=10.3390/en14030629 |doi-access=free |issn=1996-1073}}Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref> Critics see CCS as an unproven, expensive technology that will perpetuate dependence on fossil fuels.<ref name=":73">{{Cite news |last=Lakhani |first=Nina |date=2024-08-29 |title=US leads wealthy countries spending billions of public money on unproven 'climate solutions' |url=https://www.theguardian.com/business/article/2024/aug/29/unproven-climate-solutions-spending |access-date=2024-09-21 |work=The Guardian |language=en-GB |issn=0261-3077}}</ref> They believe other ways to reduce emissions are more effective and that CCS is a distraction.<ref name=":73" /> They would rather see government funds go to initiatives that are not connected to the fossil fuel industry.<ref name=":73" /> 

=== Fossil fuel abatement ===
In international climate negotiations, a controversial issue has been whether to phase out use of fossil fuels generally or to phase out use of "unabated" fossil fuels.  In the 2023 United Nations Climate Change Conference, an agreement was reached to phase down unabated coal use.<ref name=":6">{{Cite web |last1=Khourdajie |first1=Alaa Al |last2=Bataille |first2=Chris |last3=Nilsson |first3=Lars J. |date=2023-12-13 |title=The COP28 climate agreement is a step backwards on fossil fuels |url=https://theconversation.com/the-cop28-climate-agreement-is-a-step-backwards-on-fossil-fuels-219753 |access-date=2024-10-01 |website=The Conversation |language=en-US}}</ref> The term ''abated'' is generally understood to mean the use of CCS, however the agreement left the term undefined.<ref name=":6" /> 

Since the terms ''abated'' and ''unabated'' were not defined, the agreement was criticized for being open to abuse.<ref name=":6" /> Without a clear definition, is possible for fossil fuel use to be called "abated" if it uses CCS only in a minimal fashion, such as capturing only 30% of the emissions from a plant.<ref name=":6" /> 

The IPCC considers fossil fuels to be unabated if they are "produced and used without interventions that substantially reduce the amount of GHG emitted throughout the life-cycle; for example, capturing 90% or more from power plants, or 50–80% of fugitive methane emissions from energy supply."<ref>{{Cite web |date=4 April 2022 |title=WGIII Summary for Policymakers Headline Statements |url=https://www.ipcc.ch/report/ar6/wg3/resources/spm-headline-statements/ |access-date=2024-10-02 |website=Intergovernmental Panel on Climate Change |language=en}}</ref>  The intention of the IPCC definition is to require both effective CCS and deep reduction of [[fugitive gas emissions]] in order for fossil fuel emissions to qualify as being "abated."<ref name=":11">{{Cite web |last=Staff |first=Carbon Brief |date=2023-12-05 |title=Q&A: Why defining the 'phaseout' of 'unabated' fossil fuels is so important at COP28 |url=https://www.carbonbrief.org/qa-why-defining-the-phaseout-of-unabated-fossil-fuels-is-so-important-at-cop28/ |access-date=2024-10-02 |website=Carbon Brief |language=en}}</ref>

== Social acceptance ==
The public has generally low awareness of CCS.<ref name=":0"/>{{Rp|page=|pages=642-643}} Public support among those who are aware of CCS has tended to be low, especially compared to public support for other emission-reduction options.<ref name=":0" />{{Rp|page=|pages=642-643}} 

A frequent concern for the public is transparency, e.g. around issues such as safety, costs, and impacts.<ref name=":72">{{Cite journal |last1=Nielsen |first1=Jacob A. E. |last2=Stavrianakis |first2=Kostas |last3=Morrison |first3=Zoe |date=2022-08-02 |editor-last=Ramanan |editor-first=Rishiram |title=Community acceptance and social impacts of carbon capture, utilization and storage projects: A systematic meta-narrative literature review |journal=PLOS ONE |language=en |volume=17 |issue=8 |pages=e0272409 |bibcode=2022PLoSO..1772409N |doi=10.1371/journal.pone.0272409 |issn=1932-6203 |doi-access=free|pmid=35917379 |pmc=9345485 }}Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref> Another factor in acceptance is whether uncertainties are acknowledged, including uncertainties around potentially negative impacts on the natural environment and public health.<ref name=":72" />  Research indicates that engaging comprehensively with communities increases the likelihood of project success compared to projects that do not engage the public.<ref name=":72" /> Some studies indicate that community collaboration can contribute to the avoidance of harm within communities impacted by the project.<ref name=":72" />

== Government programs ==
Almost all CCS projects operating today have benefited from government financial support, largely in the form of capital grants and – to a lesser extent – operational subsidies.<ref name=":44" />{{Rp|page=|pages=156-160}} Tax credits are offered in some countries.<ref>{{Cite web |title=Inflation Reduction Act 2022: Sec. 13104 Extension and Modification of Credit for Carbon Oxide Sequestration – Policies |url=https://www.iea.org/policies/16255-inflation-reduction-act-2022-sec-13104-extension-and-modification-of-credit-for-carbon-oxide-sequestration |access-date=2024-10-10 |website=IEA |language=en-GB}}</ref><ref name=":16" /> Grant funding has played a particularly important role in projects coming online since 2010, with 8 out of 15 projects receiving grants ranging from around USD 55 million (AUD 60 million) in the case of Gorgon in Australia to USD 840 million (CAD 865 million) for [[Quest Carbon Capture and Storage Project|Quest]] in Canada. An explicit carbon price has supported CCS investment in only two cases to date: the Sleipner and Snøhvit projects in Norway.<ref name=":44" />{{Rp|page=|pages=156–160}} 

=== North America ===
As a means to help boost domestic oil production, the US federal tax code has had some sort of incentive for enhanced oil recovery since 1979, when crude oil was still under federal price controls. A 15 percent tax credit was codified with the U.S. Federal EOR Tax Incentive in 1986, and oil production from EOR using {{CO2}} subsequently grew rapidly.<ref>{{Cite web |last=National Energy Technology Laboratory |date=March 2010 |title=Carbon Dioxide Enhanced Oil Recovery: Untapped Domestic Energy Supply and Long Term Carbon Storage Solution |url=https://www.netl.doe.gov/sites/default/files/netl-file/CO2_EOR_Primer.pdf |website=U.S, Department of Energy |page=17}}{{Source-attribution}}</ref> 

In the U.S., the 2021 [[Infrastructure Investment and Jobs Act]] designates over $3&nbsp;billion for a variety of CCS demonstration projects. A similar amount is provided for regional CCS hubs that focus on the broader capture, transport, and either storage or use of captured {{CO2}}. Hundreds of millions more are dedicated annually to loan guarantees supporting {{CO2}} transport infrastructure.<ref name="mintz.com">{{Cite web |date=2022-01-05 |title=Biden's Infrastructure Law: Energy & Sustainability Implications {{!}} Mintz |url=https://www.mintz.com/insights-center/viewpoints/2151/2022-01-05-bidens-infrastructure-law-energy-sustainability |access-date=2023-09-21 |website=www.mintz.com |language=en}}</ref> 

The [[Inflation Reduction Act]] of 2022 (IRA) updates tax credit law to encourage the use of carbon capture and storage. Tax incentives under the law provide up to $85/tonne for {{CO2}} capture and storage in saline geologic formations or up to $60/tonne for {{CO2}}  used for enhanced oil recovery.<ref name="auto4">{{Cite web |title=Carbon Capture Provisions in the Inflation Reduction Act of 2022 |url=https://www.catf.us/resource/carbon-capture-provisions-in-the-inflation-reduction-act-of-2022/ |access-date=2023-09-21 |website=Clean Air Task Force |language=en}}</ref> The [[Internal Revenue Service]] relies on documentation from the corporation to substantiate claims on how much {{CO2}} is being sequestered, and does not perform independent investigations.<ref name=":10"/> In 2020, a federal investigation found that claimants for the 45Q tax credit failed to document successful geological storage for nearly $900 million of the $1 billion they had claimed.<ref name=":113"/>  

In 2023 the [[United States Environmental Protection Agency|US EPA]] issued a rule proposing that CCS be required in order to achieve a 90% emission reduction for existing coal-fired and natural gas power plants. That rule would become effective in the 2035-2040 time period.''<ref name="auto2">{{Cite web |title=Fact Sheet: Greenhouse Gas Standards and Guidelines for Fossil Fuel Fired Power Plants Proposed Rule |url=https://www.epa.gov/system/files/documents/2023-05/FS-OVERVIEW-GHG-for%20Power%20Plants%20FINAL%20CLEAN.pdf |access-date=September 20, 2023 |website=EPA}}</ref>'' For natural gas power plants, the rule would require 90 percent capture of CO<sub>2</sub> using CCS by 2035, or co-firing of 30% low-GHG hydrogen beginning in 2032 and co-firing 96% low-GHG hydrogen beginning in 2038.''<ref name="auto2" />'' Within the US, although the federal government may fully or partially fund CCS pilot projects, local or community jurisdictions would likely administer CCS project siting and construction.<ref>{{Cite journal |last1=Oltra |first1=Christian |last2=Upham |first2=Paul |last3=Riesch |first3=Hauke |last4=Boso |first4=Àlex |last5=Brunsting |first5=Suzanne |last6=Dütschke |first6=Elisabeth |last7=Lis |first7=Aleksandra |date=May 2012 |title=Public Responses to Co 2 Storage Sites: Lessons from Five European Cases |url=http://journals.sagepub.com/doi/10.1260/0958-305X.23.2-3.227 |journal=Energy & Environment |language=en |volume=23 |issue=2–3 |pages=227–248 |bibcode=2012EnEnv..23..227O |doi=10.1260/0958-305X.23.2-3.227 |issn=0958-305X |s2cid=53392027}}</ref> CO<sub>2</sub> pipeline safety is overseen by the  [[Pipeline and Hazardous Materials Safety Administration]],<ref>{{Cite web |title=Statement: DOE Welcomes New Carbon Dioxide Pipeline Safety Measures Announced by the U.S. Department of Transportation's Pipeline and Hazardous Materials Safety Administration |url=https://www.energy.gov/fecm/articles/statement-doe-welcomes-new-carbon-dioxide-pipeline-safety-measures-announced-us |access-date=2024-09-30 |website=Energy.gov |language=en}}</ref> which has been criticized as being underfunded and understaffed.<ref>{{Cite web |last1=Restuccia |first1=Andrew |last2=Schor |first2=Elana |date=July 13, 2015 |title='Pipelines blow up and people die' - POLITICO |website=[[Politico]] |url=https://www.politico.com/story/2015/04/the-little-pipeline-agency-that-couldnt-217227 |access-date=2024-09-30}}</ref>

Canada established a tax credit for CCS equipment for 2022–2028.<ref name=":16">{{Cite news |date=2022-04-07 |title=Canada creates carbon-capture incentives, critical mineral plan to cut emissions |url=https://www.reuters.com/business/sustainable-business/canada-creates-carbon-capture-incentives-critical-mineral-plan-cut-emissions-2022-04-07/ |access-date=2024-10-10 |work=Reuters}}</ref> The credit is 50% for CCS capture equipment and 37.5% for transportation and storage equipment.<ref name=":16" /> The [[Canadian Association of Petroleum Producers]] had asked for a 75% credit.<ref name=":16" /> The federal tax credit was expected to cost the government CAD $2.6 billion over 5 years;<ref name=":16" /> in 2024 the [[Parliamentary Budget Officer]] estimated it would cost CAD $5.7 billion.<ref>{{Cite news |last=Thurton |first=David |date=2024-02-01 |title=Carbon capture tax credit could cost taxpayers $1B more than expected, PBO warns |url=https://www.cbc.ca/news/politics/carbon-capture-tax-credit-climate-pbo-1.7101808 |access-date=2024-10-10 |work=CBC News}}</ref> Saskatchewan extended its 20 per cent tax credit under the province's Oil Infrastructure Investment Program to pipelines carrying CO<sub>2</sub>.<ref>{{Cite web |last=Piller |first=Thomas |date=8 September 2021 |title=Saskatchewan government lays out carbon capture utilization, storage priorities |url=https://globalnews.ca/news/8173691/saskatchewan-carbon-capture-ccus-outline/ |access-date=2025-01-11 |website=Global News |language=en-US}}</ref>

=== Europe ===
In [[Norway]], CCS has been part of a strategy to make fossil fuel exports compatible with national emission-reduction goals.<ref>{{cite journal |last1=Røttereng |first1=Jo-Kristian S. |date=May 2018 |title=When climate policy meets foreign policy: Pioneering and national interest in Norway's mitigation strategy |journal=Energy Research & Social Science |volume=39 |pages=216–225 |bibcode=2018ERSS...39..216R |doi=10.1016/j.erss.2017.11.024}}</ref> In 1991, the government introduced a tax on CO<sub>2</sub> emissions from offshore oil and gas production.<ref>{{Cite web |date=2016-11-15 |title=20 years of carbon capture and storage – Analysis |url=https://www.iea.org/reports/20-years-of-carbon-capture-and-storage |access-date=2024-10-11 |website=IEA |language=en-GB}}</ref>{{Rp|page=20}} This tax, combined with favorable and well-understood site geology, was a reason [[Equinor]] chose to implement CCS in the Sleipner and [[Snøhvit]] gas fields.<ref name=":44" /> In June 2025, Norway also launched the world’s largest full-scale operation of industrial carbon capture and storage.<ref>{{Cite news |last=Milne |first=Richard |date=2025-06-17 |title=Norway launches full-scale industrial carbon capture project with billions in subsidies |url=https://www.ft.com/content/3c24e938-9eb0-438f-8db4-5c69733af6ec |access-date=2025-06-18 |work=Financial Times}}</ref>  

In 2022, Denmark announced up to €5&nbsp;billion in subsidies for CCS, aiming to reduce emissions by 0.9Mt of CO<sub>2</sub> by 2030.<ref>{{cite web |title=Designing Carbon Contracts for Difference |url=https://www.catf.us/resource/designing-carbon-contracts-for-difference/ |website=Clean Air Task Force |access-date=6 January 2025 |archive-url=https://web.archive.org/web/20241005231130/https://www.catf.us/resource/designing-carbon-contracts-for-difference/ |archive-date=5 October 2024 |language=en |date=12 February 2024}}</ref>

In the UK the CCUS roadmap outlines joint government and industry commitments to the deployment of CCUS and sets out an approach to delivering four CCUS low carbon industrial clusters, capturing 20–30 Mt{{CO2}} per year by 2030.<ref name="auto">{{Cite web |date=April 2023 |title=CCUS Net Zero Investment Roadmap |url=https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1167167/ccus-investment-roadmap.pdf |access-date=September 21, 2023 |website=HM Government}}</ref>
In September 2024 the UK government announced £21.7bn of subsidy over 25 years for the HyNet CCS and blue hydrogen scheme in Merseyside and the East Coast Cluster scheme in Teesside.<ref>{{Cite news |last1=Partington |first1=Richard |last2=Ambrose |first2=Jillian |date=2024-10-03 |title=Labour to commit almost £22bn to fund carbon capture and storage projects |url=https://www.theguardian.com/environment/2024/oct/04/labour-to-commit-almost-22bn-to-fund-carbon-capture-and-storage-projects |access-date= |work=The Guardian |language=en-GB |issn=0261-3077}}</ref>

=== Asia ===
The Chinese State Council has now issued more than 10 national policies and guidelines promoting CCS, including the Outline of the 14th Five-Year Plan (2021–2025) for National Economic and Social Development and Vision 2035 of China.<ref name="auto3">{{Cite web |title=2022 Status Report |url=https://status22.globalccsinstitute.com/2022-status-report/introduction/ |access-date=2023-09-21 |website=Global CCS Institute |at=Page 6 |language=en-AU}}</ref> 

==Related concepts==
{{See also|Methanol fuel#Green methanol|l1=Green methanol}}
=== CO<sub>2</sub> utilization in products ===
[[File:10mm-aggregate.jpg|alt=Photo of an outstretched hand containing gravel|thumb|Incorporating carbon dioxide into [[Construction aggregate|building aggregate]] would sequester it indefinitely. ]]
CO<sub>2</sub> can be used as a feedstock for making various types of products. As of 2022, usage in products consumes around 1% of the CO<sub>2</sub> captured each year.<ref>{{Cite journal |last1=Martin-Roberts |first1=Emma |last2=Scott |first2=Vivian |last3=Flude |first3=Stephanie |last4=Johnson |first4=Gareth |last5=Haszeldine |first5=R. Stuart |last6=Gilfillan |first6=Stuart |date=November 2021 |title=Carbon capture and storage at the end of a lost decade |url=https://linkinghub.elsevier.com/retrieve/pii/S2590332221006096 |journal=One Earth |volume=4 |issue=11 |pages=1645–1646 |doi=10.1016/j.oneear.2021.10.023 |bibcode=2021OEart...4.1645M |issn=2590-3322 |access-date=2024-06-21 |hdl-access=free |hdl=20.500.11820/45b9f880-71e1-4b24-84fd-b14a80d016f3}}</ref> In the production of [[urea]], an important agricultural fertilizer, CO<sub>2</sub> generated within an industrial process is often recycled and reused. However, by convention, this type of internal recycling is not included in figures on carbon capture.<ref name=":17" /> Similarly, CO<sub>2</sub> produced for the food and beverage industry is also excluded from these figures<ref name=":17">{{Cite web |title=CCUS Projects Database - Data product |url=https://www.iea.org/data-and-statistics/data-product/ccus-projects-database# |access-date=2024-10-16 |website=IEA |language=en-GB}}</ref>   

As of 2023, it is commercially feasible to produce the following products from captured CO<sub>2:</sub> [[Green methanol|methanol]], urea, [[Polycarbonate|polycarbonates]], [[polyols]], [[polyurethane]], and [[Salicylic acid|salicylic acids]].<ref name=":03">{{Cite journal |last1=Dziejarski |first1=Bartosz |last2=Krzyżyńska |first2=Renata |last3=Andersson |first3=Klas |date=June 2023 |title=Current status of carbon capture, utilization, and storage technologies in the global economy: A survey of technical assessment |journal=Fuel |volume=342 |pages=127776 |doi=10.1016/j.fuel.2023.127776 |issn=0016-2361 |doi-access=free |bibcode=2023Fuel..34227776D }}[[File:CC-BY_icon.svg|50x50px]] Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref>  Methanol is currently primarily used to produce other chemicals, with potential for [[Methanol economy|more widespread future use]] as a fuel.<ref name=":24">{{Cite journal |last1=Kim |first1=Changsoo |last2=Yoo |first2=Chun-Jae |last3=Oh |first3=Hyung-Suk |last4=Min |first4=Byoung Koun |last5=Lee |first5=Ung |date=November 2022 |title=Review of carbon dioxide utilization technologies and their potential for industrial application |journal=Journal of CO2 Utilization |volume=65 |pages=102239 |doi=10.1016/j.jcou.2022.102239 |issn=2212-9820|doi-access=free |bibcode=2022JCOU...6502239K }}</ref> 

Technologies for sequestering CO<sub>2</sub> in mineral carbonate products have been demonstrated, but are not ready for commercial deployment as of 2023.<ref name=":03" /> Research is ongoing into processes to incorporate CO<sub>2</sub> into [[concrete]] or [[building aggregate]]. The utilization of CO<sub>2</sub> in construction materials holds promise for deployment at large scale,<ref name=":32">{{Cite journal |last1=Li |first1=Ning |last2=Mo |first2=Liwu |last3=Unluer |first3=Cise |date=November 2022 |title=Emerging CO<sub>2</sub> utilization technologies for construction materials: A review |url=https://doi.org/10.1016/j.jcou.2022.102237 |journal=Journal of CO2 Utilization |volume=65 |pages=102237 |doi=10.1016/j.jcou.2022.102237 |issn=2212-9820}}[[File:CC-BY_icon.svg|50x50px]] Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref> and is the only foreseeable CO<sub>2</sub> use that is permanent enough to qualify as ''storage''.<ref name=":15">{{Cite web |title=CO<sub>2</sub> Capture and Utilisation - Energy System |url=https://www.iea.org/energy-system/carbon-capture-utilisation-and-storage/co2-capture-and-utilisation |access-date=2024-07-18 |website=IEA |language=en-GB}}[[File:CC-BY_icon.svg|50x50px]] Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]]</ref> Other potential uses for captured CO<sub>2</sub> that are being researched include the creation of [[synthetic fuels]], and various chemicals and plastics.<ref name=":03" /> The production of fuels and chemicals from CO<sub>2</sub> is highly energy-intensive.<ref name=":15" />

Capturing CO<sub>2</sub>  for use in products does not necessarily reduce emissions.<ref name=":44" />{{Rp|page=111}} The climate benefits associated with CO<sub>2</sub> use primarily arise from displacing products that have higher life-cycle emissions.<ref name=":44" />{{Rp|page=111}} The amount of climate benefit varies depending on how long the product lasts before it re-releases the CO<sub>2</sub>, the amount and source of energy used in production, whether the product would otherwise be produced using fossil fuels, and the source of the captured CO<sub>2</sub>.<ref name=":44" />{{Rp|page=111}} Higher emissions reductions are achieved if CO<sub>2</sub> is captured from bioenergy as opposed to fossil fuels.<ref name=":44" />{{Rp|page=111}}

The potential for CO<sub>2</sub> utilization in products is small compared to the total volume of CO<sub>2</sub> that could foreseeably be captured. For instance, in the IEA scenario for achieving net zero emissions by 2050, over 95% of captured CO<sub>2</sub> is geologically sequestered and less than 5% is used in products.<ref name=":15" /> 

According to the IEA, products created from captured CO<sub>2</sub> are likely to cost a lot more than conventional and alternative low-carbon products.<ref name=":44" />{{Rp|page=110}} One important use of captured CO<sub>2</sub> would be to produce [[Electrofuel|synthetic hydrocarbon fuels]], which alongside biofuels are the only practical alternative to fossil fuels for long-haul flights. Limitations on the availability of sustainable biomass mean that these synthetic fuels will be needed for net-zero emissions; the CO<sub>2</sub> would need to come from bioenergy production or direct air capture to be carbon-neutral.<ref name=":44" />{{Rp|page=|pages=21–24}}

=== Direct air carbon capture and sequestration ===
{{Main|Direct air capture}}
Direct air carbon capture and sequestration (DACCS) is the use of chemical or physical processes to extract CO<sub>2</sub>  directly from the ambient air and putting the captured CO<sub>2</sub> into long-term storage.<ref>{{Cite web |last= |title=DOE Explains...Direct Air Capture |url=https://www.energy.gov/science/doe-explainsdirect-air-capture |access-date=2025-01-07 |website=US Department of Energy |language=en}}</ref> In contrast to CCS, which captures emissions from a point source, DAC has the potential to remove carbon dioxide that is already in the atmosphere. Thus, DAC can be used to capture emissions that originated in non-stationary sources such as airplane engines.<ref name="Erans Sanz-Pérez Hanak et al 2022">{{cite journal |last1=Erans |first1=María |last2=Sanz-Pérez |first2=Eloy S. |last3=Hanak |first3=Dawid P. |last4=Clulow |first4=Zeynep |last5=Reiner |first5=David M. |last6=Mutch |first6=Greg A. |date=2022 |title=Direct air capture: process technology, techno-economic and socio-political challenges |journal=Energy & Environmental Science |volume=15 |issue=4 |pages=1360–1405 |doi=10.1039/D1EE03523A |s2cid=247178548 |doi-access=free |bibcode=2022EnEnS..15.1360E |hdl-access=free |hdl=10115/19074}}</ref>  As of 2023, DACCS has yet to be integrated into [[Carbon emission trading|emissions trading]] because, at over US$1000,<ref name=":33">{{cite news |date=20 November 2023 |title=Carbon-dioxide-removal options are multiplying |url=https://www.economist.com/special-report/2023/11/20/carbon-dioxide-removal-options-are-multiplying |newspaper=The Economist}}</ref> the cost per ton of carbon dioxide is many times the [[carbon price]] on those markets.<ref>{{cite news |date=20 November 2023 |title=The many prices of carbon dioxide |url=https://www.economist.com/special-report/2023/11/20/the-many-prices-of-carbon-dioxide |newspaper=The Economist}}</ref>

== See also ==
{{Portal|Energy}}
{{Div col}}
* [[List of carbon capture and storage projects]]
* [[Timeline of carbon capture and storage]]
* [[Coal pollution mitigation]] 
* [[Carbon sink]]
* [[Carbon storage in the North Sea]]
* [[Greenwashing]]
* [[Life-cycle greenhouse gas emissions of energy sources]]
* [[Methane pyrolysis]]
* [[Alberta Carbon Trunk Line]]
{{div col end}}

==References==
{{Reflist}}
===Sources===
*{{Cite book  |ref= {{harvid|IPCC AR5 WG3|2014}}<!-- ipcc:20200216 -->
 |author = IPCC |author-link = IPCC
 |year= 2014
 |title= Climate Change 2014: Mitigation of Climate Change
 |series= Contribution of Working Group III to the [[IPCC Fifth Assessment Report|Fifth Assessment Report]] of the Intergovernmental Panel on Climate Change
 |display-editors= 4
 |editor-first1= O.    |editor-last1= Edenhofer
 |editor-first2= R.    |editor-last2= Pichs-Madruga
 |editor-first3= Y.    |editor-last3= Sokona
 |editor-first4= E.    |editor-last4= Farahani
 |editor-first5= S.    |editor-last5= Kadner
 |editor-first6= K.    |editor-last6= Seyboth
 |editor-first7= A.    |editor-last7= Adler
 |editor-first8= I.    |editor-last8= Baum
 |editor-first9= S.    |editor-last9= Brunner
 |editor-first10= P.   |editor-last10= Eickemeier
 |editor-first11= B.   |editor-last11= Kriemann
 |editor-first12= J.   |editor-last12= Savolainen
 |editor-first13= S.   |editor-last13= Schlömer
 |editor-first14= C.   |editor-last14= von Stechow
 |editor-first15= T.   |editor-last15= Zwickel
 |editor-first16= J.C. |editor-last16= Minx
 |publisher= Cambridge University Press
 |place= Cambridge, United Kingdom and New York, NY, USA
 |isbn=  978-1-107-05821-7
 |url= https://archive.ipcc.ch/pdf/assessment-report/ar5/wg3/ipcc_wg3_ar5_full.pdf
}} (pb: {{ISBNT|978-1-107-65481-5}}). [https://archive.ipcc.ch/report/ar5/wg3/ Fifth Assessment Report - Mitigation of Climate Change].

==External links==
*{{commons category-inline}}
*[https://www.iea.org/data-and-statistics/data-tools/ccus-projects-explorer IEA database]
*[https://zeroemissionsplatform.eu/ Zero Emissions Platform - technical adviser to the EU Commission on the deployment of CCS and CCU]
{{Climate change}}{{Authority control}}

{{DEFAULTSORT:Carbon Capture And Storage}}
[[Category:Carbon capture and storage]]
[[Category:Bright green environmentalism]]
[[Category:Emissions reduction]]
[[Category:Gas technologies]]
[[Category:Climate change and the environment]]
[[Category:Climate change mitigation]]
[[Category:Applications of carbon dioxide]]
[[Category:Greenwashing]]
[[Category:Industrial processes]]