The past couple of years has seen increased global attention and investment in carbon capture technology as a way to capture the emissions causing climate change before they enter the atmosphere. This technology has been further amplified by recent U.S. legislation — the Bipartisan Infrastructure Law and Inflation Reduction Act — which provide billions of dollars to support carbon capture, utilization and sequestration (CCUS) development and deployment.
Today CCUS captures around 0.1% of global emissions — around 45 million metric tons of carbon dioxide (CO2). Climate models from the Intergovernmental Panel on Climate Change (IPCC) and the International Energy Agency show it capturing around 1 billion metric tons of carbon dioxide (CO2) by 2030 and several billions of tons by 2050.
But not everyone sees CCUS as part of the climate solution. Some countries are moving ahead with CCUS deployment, while others are skeptical of its use. Some nongovernment organizations and other stakeholders oppose CCUS, arguing that it creates a moral hazard and that it’s only a band-aid over what they see as the real problem: ending use of fossil fuels. They point to a mixed record of success, high costs and disproportionate impacts on vulnerable communities among reasons to not rely on CCUS.
At this year’s UN climate summit (COP28) in Dubai, the role of carbon capture technologies in meeting long-term climate goals is expected to be a focus in negotiations around the urgent need to shift away from fossil fuels. The topic is especially heated as its host — the United Arab Emirates — has announced plans to use CCUS in its oil and gas sector, potentially prolonging fossil fuel use.
This article addresses key questions around the role of CCUS, including where the technology is today, in which sectors it will be most useful, and how much of the total mitigation need it can provide to help meet global climate targets.
1) What is Carbon Capture, Utilization and Sequestration (CCUS)?
Carbon capture technology combined with utilization (sometimes referenced as “use”) or sequestration (sometimes referenced as “storage”) is a way to reduce CO2 from emissions sources (such as power plants or industrial facilities) using different technologies that separate CO2 from the other gases coming out of a facility. The CO2 is thus captured before entering the atmosphere and then either permanently stored underground or incorporated into certain types of products, such as concrete or chemicals.
2) Is Carbon Capture the Same as Carbon Removal?
No, CCUS is not the same as carbon removal. Carbon dioxide removal (or just “carbon removal”) removes CO2 that is already in the atmosphere. Carbon removal includes a range of approaches from familiar things like tree restoration, to newer technological approaches like direct air capture and carbon mineralization. Another type of carbon removal is bioenergy with carbon capture and sequestration, where biomass is combusted, and carbon capture technology is used to capture those emissions before they enter the atmosphere. Even though this process involves carbon capture at an emissions source, it is considered a type of carbon removal because the captured CO2 originally came from the air via photosynthesis in the biomass that was combusted.
While CCUS and carbon dioxide removal differ on where CO2 is collected, both CCUS and some types of carbon removal require somewhere to sequester the captured CO2.
Captured CO2 — either from emission sources or from the air — can be pumped underground into certain geological formations where it is permanently sequestered, or it can be used in products ranging from concrete to chemicals to synthetic fuels. If used in products, the duration of sequestration depends on the product: For example, if CO2 is used to produce synthetic fuel, it would be re-emitted when the fuel is combusted, while CO2 used in concrete would be sequestered permanently.
CCUS is one of many ways to reduce emissions and plays a different role from carbon removal in long-term and net-zero climate plans developed by countries or companies. While emissions reduction — including CCUS and many other options — should make up the vast majority of mitigation in those plans, carbon removal can be used to counterbalance a much smaller portion of emissions that are too hard to abate with other means. In the longer-term, carbon removal is also needed to achieve and sustain net-negative emissions to reduce the excess CO2 in the atmosphere that is causing harmful climate impacts.
Notably, the term “carbon management” can be used to include both CCUS and carbon removal, which can be misleading because along with playing different roles in reaching net-zero, CCUS and carbon removal have different risks, benefits and social and environmental impacts.
3) Which Sectors Use CCUS? Which sectors need CCUS the Most to Decarbonize?
The main sectors where CCUS can be deployed are power and industry — whether it makes sense to use CCUS in those sectors will depend on costs, feasibility of other decarbonization options, and other project- and location-specific factors.
In the industrial sector, production of materials such as cement, steel and chemicals will likely need CCUS to fully decarbonize in the near-term because other decarbonization approaches do not exist or are in earlier stages of development. Current production methods for these industrial products include chemical reactions that inherently release CO2 leading to “process emissions” as well as fuel combustion for high temperatures that causes “thermal emissions.” CCUS can be used to abate both process emissions and thermal emissions, making it a particularly impactful decarbonization option for industry if scaled.
CCUS can also be used in oil and gas refining, another part of the industrial sector, to reduce emissions associated with the production of fuels used in heavy industries, transportation and power. However, the current rates of oil and gas use are incompatible with limiting global warming to 1.5 degrees C (2.7 degrees F), the target set by the Paris Agreement to ensure the world avoids the worst impacts of climate change, and using CCUS on refineries should not be a reason for that to continue. Lowering emissions associated with production does not reduce the emissions from these fuels when they’re ultimately combusted.
Within the power sector, the IPCC and other credible modeling indicate that CCUS is one option for the clean, firm power that can complement solar and wind that are likely to predominantly supply the grid. (Other options for clean, firm power include hydropower, geothermal, hydrogen, nuclear and long-duration storage.) The actual deployment of CCUS will depend in part on its costs when fully commercialized along with individual country resources and circumstances.
In these sectors, it’s crucial to note that the use of CCUS should not be seen as a license to perpetuate the use of fossil fuels – particularly in the power sector where many other options are commercially available today. CCUS could play an indispensable role in the industrial sector but isn’t a silver bullet. Overall, the use of CCUS will need to be accompanied by a steep decline in the production and use of fossil fuels along with other decarbonization options to address remaining emissions.
4) How Much Carbon Dioxide is CCUS Currently Capturing?
According to recent reports — and depending on the source — there are around 40 operational CCUS projects globally, with about 25 under construction, and more than 300 in some stage of planning. Operational projects are capturing between 42 and 49 million metric tons of CO2 per year (MtCO2/yr). If all projects in development were complete, total CCUS capacity would be around 360 MtCO2/yr, which is around 0.7% of today’s global greenhouse gas emissions. Currently, North America leads in operational projects, with most applications in the natural gas processing and ethanol industries, where capturing CO2 is relatively less expensive than in other subsectors. Other regions, such as Europe and the Middle East have a handful of operational projects as well, along with a growing number of announced projects in Europe, East Asia, the Middle East and Oceania/Australia.
Projects in the development pipeline are increasingly focused on blue hydrogen, where natural gas is used to produce hydrogen and then CO2 emissions are captured, and applications in industrial sectors like steel, cement, bioenergy, ammonia and refining.
5) How Much CCUS is Needed to Reach Net Zero and What Portion of the Total Mitigation Need Is This?
The IPCC, International Energy Agency and others find that CCUS can play a critical but limited role in addressing the climate crisis. Their analyses show that CCUS can be a complementary tool to reduce emissions where eliminating fossil fuel use or other emissions are not feasible.
The 2023 IEA Roadmap to Net Zero estimates that in order to reach net-zero in the energy sector by 2050 CCUS contributes about 8% of the total CO2 mitigation of energy sector emissions. This includes around 1 gigaton of C02 (GtCO2) in 2030 (out of a total of 13 GtCO2 abated by that date) and 5 GtCO2 in 2050 at net-zero. Notably, this roadmap just considers energy related CO2 emissions – total GHG emissions across all sectors are around 59 GtCO2e and need roughly to be halved by 2030 to limit warming to 1.5 degrees C. Considering this fuller picture, the role of CCUS would likely be a smaller percentage of total mitigation.
The IPCC Sixth Assessment Report, which examined over 200 mitigation scenarios that could limit warming to 1.5 degrees C, found that there are no scenarios in which CCUS would allow continued use of fossil fuels at current levels, let alone expansion of oil and gas production. IPCC scenarios show a wide range of potential deployment of carbon capture technology: CCUS applied to fossil fuels reduces CO2 emissions by 0 to 5 GtCO2 by 2030 with a median of 1 GtCO2. By 2050, that range is 0 to 13 GtCO2 with a median of 2 to 3 GtCO2. This means that by 2050, roughly 6% of the mitigation needed to reach net-zero could come from CCUS.
The IPCC recognizes that CCUS faces “technological, economic, institutional, ecological-environmental and socio-cultural barriers” such that current rates of CCUS deployment are far below those in most scenarios that limit global warming to 1.5 degrees C (2.7 degrees F) or 2 degrees C (3.6 degrees F). At the same time, the number of CCUS projects in the pipeline tripled in 2021 and has nearly doubled again since then. If all of the announced projects come online, capture levels could increase nearly nine times over.
6) What Are the Risks and Concerns Associated with CCUS?
Slow adoption of CCUS technology and a fear that using CCUS will perpetuate the use of fossil fuels and continue negative health and social impacts of emitting facilities are two key concerns around scaled-up implementation of CCUS.
While carbon capture has been in use since the 1970s in the United States (almost entirely for natural gas processing and for using CO2 for enhanced oil recovery), its adoption has been slow. There are not many examples to date of its successful application, and several high-profile projects have been abandoned or shuttered. Unlike many other clean technologies (such as solar photovoltaic), CCUS systems can’t be mass produced because they are specifically designed to match the facility that’s capturing the CO2. CCUS projects are also complex to coordinate because each step of the process — capture, transport and sequestration — is often owned and operated by a different company.
Additionally, each CCUS system has high upfront costs (often upwards of $1 billion) that can be prohibitive for project developers, combined with a riskier revenue structure compared to other clean technologies. Costs are expected to decline as more projects come online, the technology improves and financing costs fall.
Furthermore, today’s carbon capture systems do not capture 100% of emissions. Most are designed to capture 90%, but reported capture rates are lower in some cases. Additional energy is also required to power the capture system — depending on the application it can be 13-44% more. Access to suitable geologic sequestration sites may also be needed, and in some cases these can be far from capture sites, requiring CO2 transport.
Transport and geologic sequestration of CO2 also present risks — mainly of CO2 leakage. While CO2 in high concentrations from a pipeline leak could cause asphyxiation risk under certain circumstances, CO2 is not flammable like leaks from oil and gas pipelines. The environmental and health impacts of potential CO2 leakage are site specific and merit further research and testing to minimize them, as well as strong regulatory policy to set high standards for site characterization, monitoring, transparency and emergency response.
Concerns about Perpetuating Fossil Fuel Use
A major concern associated with CCUS is its potential to lock in fossil power production and other fossil dependent processes. Associated with this, CCUS also risks perpetuating the negative health and environmental impacts caused by emissions intensive facilities and is seen as a band-aid over these polluting industries that disproportionately harm vulnerable communities that have historically borne disproportionate levels of air pollution and toxic emissions.
Recent research shows that carbon capture systems can reduce (but not eliminate) harmful pollutants, but in many cases, community-based organizations and other advocates would prefer a facility is shut down and investment is focused instead on cleaner production processes, such as renewables in the power sector.
In the United States, where CCUS has recently received billions of dollars in government funding, the types of facilities that could be retrofitted with CCUS are often located in communities that have already borne the negative environmental and health impacts of living near power or industrial facilities. While there is evidence that CCUS can help reduce non-CO2 pollutants along with capturing CO2, many environmental justice groups are concerned that CCUS is being pushed on them without consultation and that CCUS will be used as a way to prolong a facility’s lifetime and continue the local harms it causes.
7) What Are Some Ways to Deploy CCUS Responsibly?
Responsible deployment of CCUS technology must focus not only on ensuring that the technology is effective at reducing emissions, but also that its application minimizes harm to people and the environment and maximizes benefits to them.
Robust governance and regulatory frameworks are needed to facilitate safe and effective deployment of CCUS where it is needed to reach climate goals. Regulatory frameworks should address issues such as permitting, liability and long-term monitoring as well as supportive infrastructure such as pipelines and pore space ownership for geologic sequestration sites. Regulatory frameworks should also require strategies to quantify, transparently share and minimize negative environmental and social impacts such as emission of air pollutants. Some of this work is already underway in the United States with guidance to promote responsible development and permitting of CCUS projects and state-level regulatory frameworks, starting with California. In Europe, the European Commission has developed a CCS Directive which establishes a legal framework for safe and effective geologic sequestration of CO2.
Any plan to implement CCUS must involve meaningful engagement with and buy-in from the local communities around existing facilities where project developers plan to add CCUS. A critical early step in any community engagement process is understanding community perspectives on the project and sharing information on expected local environmental and health impacts.
One outcome of this engagement process can be development of a legally binding community benefits agreement that lays out benefits the community will receive in exchange for supporting the project – such as local jobs or other types of investment. Community benefits plans, which can lead to community benefits agreements, are required in the vast majority of U.S. government funding for carbon capture and carbon removal projects.
Retrofitting a facility with CCUS does not always make sense as the first decarbonization option for technical and financial reasons. But some CO2 emission sources, particularly those in heavy industry, have few other options (such as cement process emissions). Generally, from an economic standpoint, it makes sense, to focus CCUS technology on facilities that are younger, efficient and located near suitable options for C02 sequestration or use. The ability to acquire the relevant permits and coordinate across different owners of CO2 transport and sequestration infrastructure are also critical to consider.
Companies using or planning to use CCUS at their facilities should adhere to relevant regulatory frameworks, monitor and report the environmental impacts of the technology, engage with local communities, and commit to project agreements, including community benefits agreements. These companies should also demonstrate their commitments towards responsible decarbonization by implementing other decarbonization technologies and practices along with CCUS. Along with verifying carbon removal, third party auditors could also be used to evaluate the health and environmental impacts of CCUS projects to provide greater transparency and accountability. For example, the Department of Energy is developing an initiative to recognize project developers adopting responsible carbon management practices.
What’s Next for CCUS?
CCUS will likely need to play some role in helping to meet net-zero goals. The ultimate level of scale-up required is uncertain and will depend on many factors, including how quickly other decarbonization options are developed and commercialized in different sectors, the level of policy and financial support provided, and how public perceptions shift in the coming years. At the same time, it is important to separate the technological feasibility from the policies, regulations and incentives that drive where and how it is applied. Focusing on ways to ensure that the needed applications of CCUS do not perpetuate fossil fuels or local harms related to continued operation of power or industrial facilities will be critical to making it a viable option to support reaching net zero.
The upcoming COP28 in Dubai will present a key moment to dispel the idea that CCUS could make current rates of oil and fossil gas production compatible with limiting warming to 1.5 degrees C. This notion that CCUS can allow us to avoid or slow the process phasing out fossil fuels is not only factually inaccurate but incredibly dangerous and would guarantee that we blow past our climate goals and put our collective future at risk.