Carbon capture and storage



Carbon capture and storage (CCS) is a process in which a relatively pure stream of carbon dioxide (CO2) from industrial sources is separated, treated and transported to a long-term storage location. In CCS, the CO2 is captured from a large point source, such as a chemical plant, coal power plant, cement kiln, or bioenergy plant, and typically is stored in a suitable geological formation.

CCS can reduce greenhouse gas emissions and thus mitigate climate change. For example, CCS retrofits for existing power plants can be one of the ways to limit emissions from the electricity sector and meet the Paris Agreement goals. However, as of 2022, only about one thousandth of global CO2 emissions are captured by CCS, and most of those CCS projects are for natural-gas processing. CCS projects generally aim for 90% capture efficiency, but most of the current installations have failed to meet that goal.

Storage of the captured CO2 is either in deep geological formations or in the form of mineral carbonates. Long-term predictions about submarine or underground storage security are difficult. There is still the risk that some CO2 might leak into the atmosphere. A 2018 evaluation estimates the risk of substantial leakage to be fairly low. As of 2022, around 73% of the CO2 captured annually is used for enhanced oil recovery (EOR), a process in which CO2 is injected into partially-depleted oil reservoirs in order to extract more oil and then is left underground. Since EOR utilizes the CO2 in addition to storing it, CCS is also known as carbon capture, utilization, and storage (CCUS).

CCS is so far still a relatively expensive process. Carbon capture becomes more economically viable when the carbon price is high, which is the case in much of Europe. Some environmental activists and politicians have criticized CCS as a false solution to the climate crisis. They cite the role of the fossil fuel industry in origins of the technology and in lobbying for CCS focused legislation. Critics also argue that CCS is only a justification for indefinite fossil fuel usage and equate to further investments into the environmental and social harms related to the fossil fuel industry. With regards to public support, communities who have been negatively affected by an industrial activity in the past are less supportive of CCS. Communities that feel inadequately informed about or excluded from project decision-making may also resist CCS development.

Globally, a number of laws and rules have been issued that either support or mandate the implementation of CCS. In the US, the 2021 Infrastructure Investment and Jobs Act provides support for a variety of CCS projects, and the Inflation Reduction Act of 2022 updates tax credit law to encourage the use of CCS. Other countries are also developing programs to support CCS technologies, including Canada, Denmark, China, and the UK.

Terminology
The terms carbon capture and storage (CCS), carbon capture and utilization (CCU), and carbon capture, utilization, and storage (CCUS) are closely related and often used interchangeably.

In the context of these terms, "carbon capture" refers to a process in which carbon dioxide (CO2) is separated from the other components of industrial or power plant flue gas. Once a relatively pure stream of CO2 has been captured and compressed, it can be transported and put to use ("utilized") and/or sequestered ("stored").

Terminology in this area is often inconsistent and confusing. Some institutions use these terms more broadly or more narrowly than others.

The terms CCS, CCU, and CCUS often refer to the practice of capturing CO2 and using it for enhanced oil recovery, a process in which CO2 is injected into partially-depleted oil reservoirs in order to extract more oil and then is left underground. As of 2022, around 73% of the CO2 captured annually is used for EOR. EOR is both "utilization" and "storage", as the CO2 left underground is intended to be trapped indefinitely. Prior to 2013, this practice was primarily called CCS; since then the more valuable-sounding CCUS has gained popularity.

However, CCS or CCUS can also be used to refer to the process is of injecting CO2 into underground formations such as saline aquifers where it will be trapped, without attempting to extract oil or gas. This process, called dedicated geological storage, is used for around 27% of the CO2 captured each year.

Around 1% of captured CO2 is used as a feedstock for making products such fertilizer, synthetic fuels, and plastics. These uses are forms of CCU. In some cases, the product durably stores the carbon from the CO2 and thus is also considered to be a form of CCS or CCUS. In CCS, carbon storage must be long-term, therefore utilization of  CO2  to produce fertilizer, fuel, or chemicals is not CCS because these substances release CO2  when burned or consumed.

Early uses
The natural gas industry has used carbon capture technology for decades. Raw natural gas contains CO2 that needs removal to produce a marketable product. The sale of captured CO2, mainly to oil producers for EOR, has enhanced the economic viability of natural gas development projects. CO2 removal for this purpose first occurred at The Terrell Natural Gas Processing Plant, in Terrell, Texas, US, in 1972. The use of CCS as a means of reducing anthropogenic CO2 emissions is more recent. The Sleipner CCS project, which began in 1996, and the Weyburn-Midale Carbon Dioxide Project, which began in 2000, were the first international demonstrations of the large-scale capture, utilization, and storage of anthropogenic CO2 emissions.

Role in climate change mitigation
The rationale for CCS is to allow the continued use of fossil fuels while reducing the emission of CO2 into the atmosphere, thereby mitigating global climate change.

In the 21st century CCS is employed to contribute to climate change mitigation. For example, CCS retrofits for existing power plants is one way to limit emissions from the electricity sector for meeting Paris Agreement goals. However, analyses of modeling studies indicate that over-reliance on CCS presents risks, and that global rates of CCS deployment remain far below those depicted in mitigation scenarios of the IPCC Sixth Assessment Report. Total annual CCS capacity was only 45 MtCO2 as of 2021. The implementation of default technology assumptions would cost 29-297% more over the century than efforts without CCS for a 430-480 ppm CO2/yr scenario.

As of 2018, for a below 2.0 °C target, Shared socioeconomic pathways (SSPs) had been developed adding a socio-economic dimension to the integrative work started by RCPs models. All SSPs scenarios show a shift away from unabated fossil fuels, that is processes without CCS. It was proposed that bioenergy with carbon capture and storage (BECCS) was necessary to achieve a 1.5 °C, and that with the help of BECCS, between 150 and 12,000 GtCO2 still had to be removed from the atmosphere.

A 2019 study found CCS plants to be less effective than renewable electricity. The electrical energy returned on energy invested (EROEI) ratios of both production methods were estimated, accounting for their operational and infrastructural energy costs. Renewable electricity production included solar and wind with sufficient energy storage, plus dispatchable electricity production. Thus, rapid expansion of scalable renewable electricity and storage would be preferable over fossil-fuel with CCS.

CO2 capture
Capturing CO2 is most cost-effective at point sources, such as large fossil fuel-based energy facilities, industries with major CO2 emissions (e.g. cement production, steelmaking ), natural gas processing, synthetic fuel plants and fossil fuel-based hydrogen production plants. Extracting CO2 from air is possible, although the lower concentration of CO2 in air compared to combustion sources complicates the engineering and makes the process therefore more expensive. The net storage efficiency of carbon capture projects is maximally 6–56%. About two thirds of CCS cost is attributed to capture. Optimizing capture would significantly increase CCS feasibility since the transport and storage steps of CCS are rather mature.

Impurities in CO2 streams, like sulfurs and water, can have a significant effect on their phase behavior and could cause increased pipeline and well corrosion. In instances where CO2 impurities exist, especially with air capture, a scrubbing separation process is needed to initially clean the flue gas.

A wide variety of separation techniques are being pursued, including gas phase separation, absorption into a liquid, and adsorption on a solid, as well as hybrid processes, such as adsorption/membrane systems. There are three ways that this capturing can be carried out: post-combustion capture, pre-combustion capture, and oxy-combustion:


 * In post combustion capture, the CO2 is removed after combustion of the fossil fuel—this is the scheme that would apply to fossil-fuel power plants. CO2 is captured from flue gases at power stations or other point sources. The technology is well understood and is currently used in other industrial applications, although at much smaller scale than required for a commercial operation. Post combustion capture is most popular in research because it is hoped that fossil fuel power plants can be retrofitted with CCS technology in this configuration.
 * The technology for pre-combustion is widely applied in fertilizer, chemical, gaseous fuel (H2, CH4), and power production. In these cases, the fossil fuel is partially oxidized, for instance in a gasifier. The CO from the resulting syngas (CO and H2) reacts with added steam (H2O) and is shifted into CO2 and H2. The resulting CO2 can be captured from a relatively pure exhaust stream. The H2 can be used as fuel; the CO2 is removed before combustion. Several advantages and disadvantages apply versus post combustion capture. The CO2 is removed after combustion, but before the flue gas expands to atmospheric pressure. The capture before expansion, i.e. from pressurized gas, is standard in almost all industrial CO2 capture processes, at the same scale as required for power plants.
 * In oxy-fuel combustion the fuel is burned in pure oxygen instead of air. To limit the resulting flame temperatures to levels common during conventional combustion, cooled flue gas is recirculated and injected into the combustion chamber. The flue gas consists of mainly CO2 and water vapor, the latter of which is condensed through cooling. The result is an almost pure CO2 stream. Power plant processes based on oxyfuel combustion are sometimes referred to as "zero emission" cycles, because the CO2 stored is not a fraction removed from the flue gas stream (as in the cases of pre- and post-combustion capture) but the flue gas stream itself. A fraction of the CO2 inevitably ends up in the condensed water. To warrant the label "zero emission" the water would thus have to be treated or disposed of appropriately.

Absorption, or carbon scrubbing with amines is the dominant capture technology. It is the only carbon capture technology so far that has been used industrially. Other technologies proposed for carbon capture are membrane gas separation, chemical looping combustion, calcium looping, and use of metal-organic frameworks:

After the has been captured, it is usually compressed into a supercritical fluid. The is compressed so that it can be more easily transported. Compression is done at the capture site. This process requires its own energy source. Like the capture stage, compression is achieved by increasing the parasitic load. Compression of is an energy intensive procedure that involves multi-stage complex compressors and a power-generated cooling process.

CO2 transport
Some highly pressurized is already transported via pipelines. For example, approximately 5,800 km of CO2 pipelines operated in the US in 2008, and a 160 km pipeline in Norway, used to transport CO2 to oil production sites where it is injected into older fields to extract more oil.

In 2021, two companies, namely Navigator Ventures and Summit Carbon Solutions were planning pipelines through the Midwestern US from North Dakota to Illinois to connect ethanol companies to sites where liquefied  is injected into porous rock. The Navigator Heartland Greenway pipeline project was cancelled after encountering significant local resistance to the project. As of 2023, the Summit Carbon pipeline has also been encountering significant headwinds, and is currently forecasting a COD in 2026.

Transmission pipelines may leak or rupture. A severed 19" pipeline section 8 km long could release its 1,300 tonnes in about 3–4 min. Pipelines can be fitted with remotely controlled valves that can limit the release quantity to one pipe section, however, operators have not been required to retrofit older pipes because of the nonapplication clause found at 49 U.S.C. § 60104(b), which prohibits the Pipeline and Hazardous Materials Safety Administration (PHMSA) from promulgating regulations to existing facilities.

In 2020 a CO2-pipeline exploded near Satartia, Mississippi, causing cars to stop and people to go unconscious; 45 were hospitalized, and some experienced longer term effects on their health.

The US Pipeline and Hazardous Materials Safety Administration, the agency in charge of pipeline safety, is a notoriously underfunded and understaffed agency.

CO2 sequestration (storage)
Various approaches have been conceived for permanent storage. These include gaseous storage in deep geological formations (including saline formations and exhausted gas fields), and solid storage by reaction of CO2 with metal oxides to produce stable carbonates. Storage capacity, containment efficiency and injectivity are the three factors that require major pre-assessment to decide the feasibility of CO2 storage in a candidate geological formation. Geo-sequestration, involves injecting CO2, generally in supercritical form, into underground geological formations. Oil fields, gas fields, saline formations, unmineable coal seams, and saline-filled basalt formations have been suggested as alternatives. At the molecular level, carbon dioxide is shown to affect the mechanical properties of the formation where it has been injected. Physical (e.g., highly impermeable caprock) and geochemical trapping mechanisms prevent the CO2 from escaping to the surface.

Unmineable coal seams can be used because CO2 molecules attach to the coal surface. Technical feasibility depends on the coal bed's permeability. In the process of absorption the coal releases previously absorbed methane, and the methane can be recovered (enhanced coal bed methane recovery). Methane revenues can offset a portion of the cost, although burning the resultant methane, however, produces another stream of CO2 to be sequestered.

Saline formations contain mineralized brines and have yet to produce benefit to humans. Saline aquifers have occasionally been used for storage of chemical waste in a few cases. The main advantage of saline aquifers is their large potential storage volume and their ubiquity. The major disadvantage of saline aquifers is that relatively little is known about them. To keep the cost of storage acceptable, geophysical exploration may be limited, resulting in larger uncertainty about the aquifer structure. Unlike storage in oil fields or coal beds, no side product offsets the storage cost. Trapping mechanisms such as structural trapping, residual trapping, solubility trapping and mineral trapping may immobilize the CO2 underground and reduce leakage risks.

Enhanced oil recovery
CO2 has been injected into partially depleted oil fields for several decades for enhanced oil recovery. This has been criticised for producing more emissions when the gas or oil is burned.

Long-term retention
IPCC estimates that leakage risks at properly managed sites are comparable to those associated with current hydrocarbon activity. It recommends that limits be set to the amount of leakage that can take place. However, this finding is contested given the lack of experience. CO2 could be trapped for millions of years, and although some leakage may occur, appropriate storage sites are likely to retain over 99% for over 1000 years. Several approaches to minimize the risk of leakage have been proposed and researched. There is also a proposed approach of utilizing clay-rich sandstone formations.

Mineral storage is not regarded as presenting any leakage risks.

Norway's Sleipner gas field is the oldest industrial scale retention project. An environmental assessment conducted after ten years of operation concluded that geosequestration was the most definite form of permanent geological storage method: "Available geological information shows absence of major tectonic events after the deposition of the Utsira formation [saline reservoir]. This implies that the geological environment is tectonically stable and a site suitable for CO2 storage. The solubility trapping [is] the most permanent and secure form of geological storage."

In March 2009, the national Norwegian oil company StatoilHydro (later renamed Equinor) issued a study documenting the slow spread of CO2 in the formation after more than 10 years operation.

Gas leakage into the atmosphere may be detected via atmospheric gas monitoring, and can be quantified directly via eddy covariance flux measurements.

Sudden leakage hazards
At the storage site, the injection pipe can be fitted with non-return valves to prevent an uncontrolled release from the reservoir in case of upstream pipeline damage.

Large-scale CO2 releases present asphyxiation risks. For example, in the 1953 Menzengraben mining accident, several thousand tonnes were released and asphyxiated a person 300 meters away. Malfunction of a CO2 industrial fire suppression system in a large warehouse released 50 t CO2 after which 14 people collapsed on the nearby public road.

Scale
Worldwide storage capacity in oil and gas reservoirs is estimated to be 675–900 Gt CO2, and in un-minable coal seams is estimated to be 15–200 Gt CO2. Deep saline formations have the largest capacity, which is estimated to be 1,000–10,000 Gt CO2. In the US, there is estimated to be at least 2,600 Gt and at most 22,000 Gt total CO2 storage capacity.

According to the Global CCS Institute, in 2020 there was about 40 million tons CO2 per year capacity of CCS in operation and 50 million tons per year in development. In contrast, the world emits about 38 billion tonnes of CO2 every year, so CCS captured about one thousandth of the 2020 CO2 emissions. Iron and steel is expected to dominate industrial CCS in Europe, although there are alternative ways of decarbonizing steel.

Example projects
There are a number of large-scale carbon capture and sequestration projects that have demonstrated the viability and safety of this method of carbon storage, which are summarized by the Global CCS Institute.

In September 2020, the US Department of Energy awarded $72 million in federal funding to support the development and advancement of carbon capture technologies.

One of the most well-known failures is the FutureGen program, partnerships between the US federal government and coal energy production companies which were intended to demonstrate "clean coal", but never succeeded in producing any carbon-free electricity from coal.

Cost
Cost is a significant factor affecting CCS. The cost of CCS, plus any subsidies, must be less than the expected cost of emitting CO2 for a project to be considered economically favorable.

Tests of CCS at the Petra Nova and Boundary Dam coal-fired power plants and has been found to be technically feasible but not economically viable for use with coal, due to reductions in the cost of solar PV technology.

CCS technology is expected to use between 10 and 40 percent of the energy produced by a power station. The energy consumed by CCS is called an "energy penalty". It has been estimated that about 60% of the penalty originates from the capture process, 30% comes from compression of the extracted CO2, while the remaining 10% comes from pumps and fans. CCS would increase the fuel requirement of a gas plant with CCS by about 15%. The cost of this extra fuel, as well as storage and other system costs, are estimated to increase the costs of energy from a power plant with CCS by 30–60%. This makes it more difficult for fossil fuel plants with CCS to compete with renewable energy combined with energy storage, especially as the cost of renewable energy and batteries continues to decline.

Constructing CCS units is capital-intensive. The additional costs of a large-scale CCS demonstration project are estimated to be €0.5–1.1 billion per project over the project lifetime. Other applications are possible. CCS trials for coal-fired plants in the early 21st century were economically unviable in most countries, including China, in part because revenue from enhanced oil recovery collapsed with the 2020 oil price collapse. A carbon price of at least 100 euros per tonne CO2 is estimated to be needed to make industrial CCS viable, together with carbon tariffs. But, as of mid-2022, the EU Allowance had never reached that price, and the Carbon Border Adjustment Mechanism had not yet been implemented. However, a company making small modules claims it can get well below that price by mass production by 2022.

According to UK government estimates made in the late 2010s, carbon capture (without storage) is estimated to add 7 GBP per MWh by 2025 to the cost of electricity from a gas-fired power plant. However, the CO2 will need to be stored, so in total the increase in cost for gas or biomass generated electricity is around 50%.

A 2020 study concluded that half as much CCS might be installed in coal-fired plants as in gas-fired; these would be mainly in China and India. However a 2022 study concluded that it would be too expensive for coal power in China.

Bill Gates said in 2023 that in his view CCS was unlikely to be economically viable for mass-scale use in the long term, and that "for most cases, you should use an alternative technique rather than emitting and then paying for capturing.... For everything you can, you want to solve it by never generating the carbon dioxide.”

Related impacts
Since liquid amine solutions are used to capture CO2 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, which are carcinogenic when inhaled or drunk in water. CCS systems also reduce the efficiency of the power plants that use them to control CO2. For super-critical pulverized coal (PC) plants, CCS' energy requirements range from 24 to 40%, while for coal-based gasification combined cycle (IGCC) systems it is 14–25%. Using CCS for natural gas combined cycle (NGCC) plants can decrease operating efficiency from 11 to 22%. This in turn could cause a net increase of non-GHG pollutants from those facilities. However, most of these impacts are controlled by the pollution control equipment already installed at these plants to meet air pollution regulations. CCS technology also has operational impacts. These impacts increase as the capacity factor decreases (the plant is used less - for example only for times of highest demand or in emergencies).

Other impacts occur outside the facility. As a result of efficiency losses at coal plants, fuel use and environmental problems arising from coal extraction increase. Plants equipped with flue-gas desulfurization (FGD) systems for sulfur dioxide control require proportionally greater amounts of limestone, and systems equipped with selective catalytic reduction systems for nitrogen oxides produced during combustion require proportionally greater amounts of ammonia.

Analysis of IPCC modeling work shows that mitigation strategies that rely less on CCS would bring about localized, near-term benefits from reduced air and water pollution, human rights violations, and biodiversity loss.

Monitoring
Monitoring allows leak detection with enough warning to minimize the amount lost, and to quantify the leak size. Monitoring can be done at both the surface and subsurface levels. The dominant monitoring technique is seismic imaging, where vibrations are generated that propagate through the subsurface. The geologic structure can be imaged from the refracted/reflected waves.

Subsurface
Subsurface monitoring can directly and/or indirectly track the reservoir's status. One direct method involves drilling deep enough to collect a sample. This drilling can be expensive due to the rock's physical properties. It also provides data only at a specific location.

One indirect method sends sound or electromagnetic waves into the reservoir which reflects back for interpretation. This approach provides data over a much larger region; although with less precision.

Both direct and indirect monitoring can be done intermittently or continuously.

Seismic
Seismic monitoring is a type of indirect monitoring. It is done by creating seismic waves either at the surface using a seismic vibrator, or inside a well using a spinning eccentric mass. These waves propagate through geological layers and reflect back, creating patterns that are recorded by seismic sensors placed on the surface or in boreholes. It can identify migration pathways of the CO2 plume.

Examples of seismic monitoring of geological sequestration are the Sleipner sequestration project, the Frio CO2 injection test and the CO2CRC Otway Project. Seismic monitoring can confirm the presence of CO2 in a given region and map its lateral distribution, but is not sensitive to the concentration.

Zoback and Gorelick (2012) identified the need for further study into how low to moderate intensity seismic events can impact the seal integrity of any prospective reservoirs for geologic carbon storage. Induced seismicity due to wastewater injection is widely documented; however these discussions are typically not in the context of nearby CCS storage sites. This prompts the need for a greater understanding of the risks of local and regional seismic impacts of storage integrity over time.

Tracer
Organic chemical tracers, using no radioactive or Cadmium components, can be used during the injection phase in a CCS project where CO2 is injected into an existing oil or gas field, either for EOR, pressure support or storage. Tracers and methodologies are compatible with CO2 – and at the same time unique and distinguishable from the CO2 itself or other molecules present in the sub-surface. Using laboratory methodology with an extreme detectability for tracer, regular samples at the producing wells will detect if injected CO2 has migrated from the injection point to the producing well. Therefore, a small tracer amount is sufficient to monitor large scale subsurface flow patterns. For this reason, tracer methodology is well-suited to monitor the state and possible movements of CO2 in CCS projects. Tracers can therefore be an aid in CCS projects by acting as an assurance that CO2 is contained in the desired location sub-surface. In the past, this technology has been used to monitor and study movements in CCS projects in Algeria, the Netherlands and Norway (Snøhvit).

Surface
Eddy covariance is a surface monitoring technique that measures the flux of CO2 from the ground's surface. It involves measuring CO2 concentrations as well as vertical wind velocities using an anemometer. This provides a measure of the vertical CO2 flux. Eddy covariance towers could potentially detect leaks, after accounting for the natural carbon cycle, such as photosynthesis and plant respiration. An example of eddy covariance techniques is the Shallow Release test. Another similar approach is to use accumulation chambers for spot monitoring. These chambers are sealed to the ground with an inlet and outlet flow stream connected to a gas analyzer. They also measure vertical flux. Monitoring a large site would require a network of chambers.

InSAR
InSAR monitoring involves a satellite sending signals down to the Earth's surface where it is reflected back to the satellite's receiver. The satellite is thereby able to measure the distance to that point. CO2 injection into deep sublayers of geological sites creates high pressures. These layers affect layers above and below them, change the surface landscape. In areas of stored CO2, the ground's surface often rises due to the high pressures. These changes correspond to a measurable change in the distance from the satellite.

Social acceptance
In a 2011 publication it was suggested that people who were already affected by climate change, such as drought,tended to be more supportive of CCS. As of 2014, multiple studies indicated that risk-benefit perception were the most essential components of social acceptance.

In 2021, it was suggested that risk perception was mostly related to concerns on safety issues in terms of hazards from its operations and the possibility of CO2 leakage, which may endanger communities, commodities, and the environment in the vicinity of the infrastructure. Other perceived risks relate to tourism and property values. as of 2011, CCS public perceptions appeared among other controversial technologies to tackle climate change such as nuclear power, wind, and geoengineering

Locally, communities are sensitive to economic factors, including job creation, tourism or related investment. Experience is another relevant feature: people already involved or used to industry are likely to accept the technology. In the same way, communities who have been negatively affected by any industrial activity are also less supportive of CCS. Perception of CCS has a strong geographic component. Public perception can depend on the available information about pilot projects, trust in government entities and developers involved, and awareness of successes and failures of CCS projects both locally and globally. These considerations vary by country and by community.

If only considering technical feasibility, countries with no known viable storage sites may dismiss CCS as an option in national emissions reduction strategies. In contrast, countries with several, or an abundance of viable storage sites may consider CCS as essential to reducing emissions.

Few members of the public know about CCS. This can allow misconceptions that lead to less approval. No strong evidence links knowledge of CCS and public acceptance, but one experimental study amongst Swiss people from 2011 found that communicating information about monitoring tended to have a negative impact on attitudes. Conversely, approval seems to be reinforced when CCS was compared to natural phenomena.

Connected to how public perception influences the success or failure of a CCS project is consideration for how decision-making processes are implemented equitably and meaningfully for "impacted communities" at all stages of the project. Public participation alone does not encompass all aspects of procedural justice needed for CCS projects to receive the "social license" to operate.

Due to the lack of knowledge, people rely on organizations that they trust. In general, non-governmental organizations and researchers experience higher trust than stakeholders and governments. As of 2009 Opinions amongst NGOs were mixed. Moreover, the link between trust and acceptance was at best indirect. Instead, trust had an influence on the perception of risks and benefits.

CCS is embraced by the Shallow ecology worldview, which promotes the search for solutions to the effects of climate change in lieu of/in addition to addressing the causes. This involves the use of advancing technology and CCS acceptance is common among techno-optimists.

CCS is an "end-of-pipe" solution which reduces atmospheric CO2, that can be used alongside minimizing the use of fossil fuel.

Political debate
CCS has been discussed by political actors at least since the start of the UNFCCC negotiations in the beginning of the 1990s, and remains a very divisive issue.

Some environmental groups raised concerns over leakage given the long storage time required, comparing CCS to storing radioactive waste from nuclear power stations.

Other controversies arose from the use of CCS by policy makers as a tool to fight climate change. In the IPCC's Sixth Assessment Report in 2022, most pathways to keep the increase of global temperature below 2 °C include the use of negative emission technologies (NETs).

Some environmental activists and politicians have criticized CCS as a false solution to the climate crisis. They cite the role of the fossil fuel industry in origins of the technology and in lobbying for CCS focused legislation and argue that it would allow the industry to "greenwash" itself by funding and engaging in things such as tree planting campaigns without significantly cutting their carbon emissions.

A review of studies by the Stanford Solutions Project concluded that relying on Carbon capture and storage/utilization (CCS/U) is a dangerous distraction, with it (in most and large-scale cases) being expensive, increasing air pollution and mining, inefficient and unlikely to be deployable at the scale required in time.

Government programs
In the US, a number of laws and rules have been issued to either support or require the use of CCS technologies. The 2021 Infrastructure Investment and Jobs Act designates over $3 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. Hundreds of millions more are dedicated annually to loan guarantees supporting transport infrastructure. 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 are $85/tonne for capture and storage in saline geologic formations from industrial and power plants. Incentives for capture and utilization from these plants are $60/tonne. Thresholds for the total amount of needing to be captured are also lower, and so more facilities will be able to make use of the credits. 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.

In 2023 the 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.  For natural gas power plants, the rule would require 90 percent capture of CO2 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. In that rule EPA identified CCS as a viable technology for controlling CO2 emissions.  Costs of using CCS technology were estimated to be, on average, $14/ton of CO2 reduced for coal plants. The impact on the cost of electricity generation from coal plants was estimated as $12/ MWh. These are considered by EPA to be reasonable air pollution control costs.

Other countries are also developing programs to support CCS technologies. Canada has established a C$2.6 billion tax credit for CCS projects and Saskatchewan extended its 20 per cent tax credit under the province’s Oil Infrastructure Investment Program to pipelines carrying CO2. In Europe, Denmark has recently announced €5 billion in subsidies for CCS. 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. 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 per year by 2030.

Carbon emission status-quo
Opponents claimed that CCS could legitimize the continued use of fossil fuels, as well obviate commitments on emission reduction.

Some examples such as in Norway shows that CCS and other carbon removal technologies gained traction because it allowed the country to pursue its interests regarding the petroleum industry. Norway was a pioneer in emission mitigation, and established a CO2 tax in 1991.

Maintaining the use of fossil fuels as the energy status quo extends beyond the climate impacts of their emissions. Implementing CCS to capture carbon emissions from an industrial point source can also enable the negative environmental or social impacts "upstream" of a storage site. This is particularly evident where energy resources lie in or near areas home to indigenous communities, such as the regions overlying the Bakken Formation or the Athabasca Oil Sands. Power imbalances persist between the extractive industry corporations, state, provincial, or federal governments, and the "host" communities. As a result, the impacted populations are often displaced or criminalized when seeking to defend their ancestral lands from ecological harm (see Resource Extraction in Environmental Justice).

Another aspect of CCS that could concern project opponents is that projects only remove carbon dioxide from flue gas. Particulate matter and other toxic gas emissions would continue, which is of particular concern in places in the US where industries are in poor and/or minority communities. In many cases, CCS would not markedly improve the public or environmental health of these communities.

Because CCS is an "end of pipe" technology, part of the key to its viability as a climate change solution stems from holistically evaluating the sustainability of the energy resource pipeline tied to a project.

The communities targeted for hosting CCS projects may meet the geologic and technical siting criteria; however, non-technical social characterizations are equally important factors in the success of an individual project and the global deployment of this technology. Failing to provide meaningful engagement with local communities can drive resistance to CCS projects and enable feelings of mistrust and injustice from project developers and supporting government entities.

Environmental NGOs
Environmental NGOs are not in widespread agreement about CCS as a potential climate mitigation tool. The main disagreement amid NGOs is whether CCS will reduce CO2 emissions or just perpetuate the use of fossil fuels.

For instance, Greenpeace is strongly against CCS. According to the organization, the use of the technology will keep the world dependent on fossil fuels.

On the other hand, BECCS is used in some IPCC scenarios to help meet mitigation targets. Adopting the IPCC argument that CO2 emissions need to be reduced by 2050 to avoid dramatic consequences, the Bellona Foundation justified CCS as a mitigation action. They claimed fossil fuels are unavoidable for the near term and consequently, CCS is the quickest way to reduce CO2 emissions.