Introduction to Carbon Capture and Storage (CCS)
Carbon Capture and Storage (CCS) is an industrial emissions-reduction technology that captures carbon dioxide (CO₂) from power plants, refineries, and manufacturing facilities before it enters the atmosphere. The captured CO₂ is prepared for transport, moved to a suitable storage site, and injected into carefully selected underground geological formations for long-term storage.
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| Carbon capture, compression, pipeline transportation, and underground geological storage of CO₂. |
The CCS process involves five main stages: capture, purification and compression, transportation, geological storage, and monitoring. Each stage contributes to the effective management of captured CO₂ and the long-term integrity of the storage site.
The oil and gas industry has relevant expertise in subsurface geology, reservoir engineering, and well integrity, which can support the development of suitable CO₂ storage projects. To understand these subsurface systems, explore our guide to Oil and Gas.
This guide explores how CCS works, its main capture technologies, geological storage methods, benefits, challenges, industrial applications, and its potential role in India's energy transition.
What Is Carbon Capture and Storage (CCS)?
Carbon Capture and Storage (CCS) is a technology that captures carbon dioxide (CO₂) emissions from power plants and industrial facilities before they enter the atmosphere. The captured CO₂ is processed, compressed, transported, and injected into suitable deep underground geological formations for long-term storage.
CCS is particularly relevant to industries such as cement, steel, chemicals, and oil and gas refining, where emissions arise from both fuel combustion and industrial chemical reactions. While renewable energy and energy efficiency can reduce many emissions, CCS can help address residual emissions that are difficult to eliminate through other measures alone.CCS vs CCUS: What Is the Difference?
Both approaches involve capturing CO₂, but they differ in how the captured carbon dioxide is managed.
| Feature | Carbon Capture and Storage (CCS) | Carbon Capture, Utilization and Storage (CCUS) |
|---|---|---|
| Primary goal | Capture and store CO₂ underground | Capture CO₂ for utilization and/or storage |
| Utilization | Not required; geological storage is the focus | May include synthetic fuels, chemicals, building materials, or enhanced oil recovery (EOR) |
| Climate benefit | Depends on net emissions avoided and storage performance | Depends on the application, energy requirements, and how long the CO₂ remains contained |
Key distinction: Using captured CO₂ does not automatically deliver a lasting climate benefit. For example, CO₂ used to produce synthetic fuels is generally released again when those fuels are burned. By contrast, geological storage can provide long-term containment when the site is properly selected, managed, and monitored. Some building materials can also retain CO₂ for extended periods, depending on the application and material properties.
How Does Carbon Capture and Storage (CCS) Work?
Carbon Capture and Storage (CCS) involves capturing carbon dioxide (CO₂) from industrial sources, preparing it for transportation, injecting it into suitable underground geological formations, and monitoring the storage site to assess long-term containment.
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| The five main stages of carbon capture and storage (CCS), from industrial CO₂ capture to long-term underground storage and monitoring. |
The process follows five main stages:
CO₂ Source → Capture and Separation → Purification and Compression → Transportation → Geological Storage → Monitoring and Verification
1. CO₂ Capture
Carbon dioxide is separated from industrial exhaust gases or process streams before it is released into the atmosphere. The choice of capture technology depends on factors such as CO₂ concentration, gas composition, temperature, and operating conditions.
Common capture methods include:
- Liquid Solvents: Chemical solvents, including amine-based solutions, absorb CO₂ from gas streams and release it during regeneration, allowing the solvent to be reused.
- Solid Sorbents: Porous materials capture CO₂ on their surfaces through physical or chemical adsorption.
- Membrane Separation: Specialized membranes selectively separate CO₂ from other gases based on differences in their transport properties.
2. Purification and Compression
Captured CO₂ may contain moisture and other impurities that must be reduced to levels suitable for transportation and storage. Purification and dehydration help prevent corrosion, hydrate formation, and operational problems in pipelines and other equipment.
The CO₂ is then compressed to the pressure required by the transport system. Depending on operating conditions, it may be transported as a dense-phase fluid, which reduces its volume and supports efficient bulk transportation. The required pressure and phase depend on the CO₂ composition, temperature, and project design.
3. CO₂ Transportation
After conditioning, captured CO₂ is transported from the capture facility to a designated storage site. The main transportation options include:
- Pipelines: Suitable for continuous, large-volume transportation over established routes.
- Marine Tankers: Used for transporting CO₂ over longer distances, including between countries and to offshore storage hubs.
- Road and Rail Tankers: Suitable for smaller volumes, demonstration projects, and locations without dedicated pipeline infrastructure.
Transport systems require appropriate pressure and temperature controls, leak detection, emergency shutdown systems, and inspection procedures to support safe operation.
4. Geological Storage
CO₂ is injected through specially designed wells into suitable underground geological formations, commonly deep saline formations or depleted oil and gas reservoirs. These formations must have adequate storage capacity and suitable geological characteristics.
An impermeable or low-permeability rock layer, known as caprock, helps restrict upward migration of the injected CO₂. Several trapping mechanisms contribute to storage security, including structural trapping beneath caprock, residual trapping within rock pores, dissolution into formation water, and, over longer periods, mineral trapping as CO₂ reacts to form stable carbonate minerals.
The suitability of a storage site depends on geological structure, reservoir properties, well integrity, pressure management, and the potential for CO₂ migration.
5. Monitoring, Measurement and Verification (MMV)
Monitoring, measurement, and verification help assess storage performance and identify potential risks throughout a CCS project's operating life. The techniques used depend on the site's geology, regulatory requirements, and risk assessment.
Common monitoring methods include:
- Pressure and Temperature Monitoring: Tracks changes in reservoir conditions and helps assess injection performance.
- Seismic Surveys: Use geological imaging to evaluate subsurface conditions and, where appropriate, track the movement of the injected CO₂ plume.
- Groundwater and Soil-Gas Monitoring: May be used to establish baseline conditions and investigate potential leakage pathways.
- Well-Integrity Inspections: Assess injection wells and other relevant wells to help prevent unintended CO₂ migration.
Together, these stages form an integrated CCS system. Its effectiveness depends not only on the amount of CO₂ captured but also on energy requirements, transport efficiency, suitable geological storage, and effective long-term monitoring.
Types of Carbon Capture Technologies
Carbon capture technologies are used to separate carbon dioxide (CO₂) from industrial gases or the atmosphere. The four main types are post-combustion capture, pre-combustion capture, oxy-fuel combustion, and direct air capture (DAC).
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| Four major carbon capture technologies used to separate CO₂ from industrial emissions or directly from the air. |
1. Post-Combustion Capture
Post-combustion capture removes CO₂ from exhaust gases after fuel has been burned.
- How It Works: Exhaust gases pass through a system containing a chemical solvent, such as an amine solution, that absorbs CO₂. The solvent is then heated to release the captured CO₂. Afterward, the solvent is reused.
- Key Advantage: This technology can be installed in many existing coal-fired power plants, gas-fired power plants, cement factories, and industrial boilers.
- Main Limitation: Heating the solvent requires energy, which can increase operating costs and reduce the facility's overall efficiency.
2. Pre-Combustion Capture
Pre-combustion capture separates CO₂ before the fuel gas is burned to produce energy.
- How It Works: Fuels such as natural gas, coal, or biomass can be converted into a gas mixture containing hydrogen and carbon monoxide. Steam is then added to convert carbon monoxide into carbon dioxide and additional hydrogen.Chemical Reaction:CO + H₂O → CO₂ + H₂. The CO₂ is separated from the gas mixture, leaving a hydrogen-rich gas that can be used as fuel or in industrial processes.
- Key Advantage: CO₂ is often available at higher pressure and concentration, which can make it easier to separate.
- Main Limitation: The process requires specialised equipment and is mainly suitable for certain hydrogen production, ammonia manufacturing, and gasification facilities.
3. Oxy-Fuel Combustion
Oxy-fuel combustion burns fuel using oxygen instead of ordinary air. Recycled exhaust gas may also be used to control the combustion temperature.
- How It Works: Ordinary air contains nitrogen, which mixes with combustion gases. Using oxygen instead of air reduces the amount of nitrogen entering the combustion process. The resulting exhaust gas contains mainly CO₂ and water vapour. After the water is removed, the CO₂ can be purified and compressed.
- Key Advantage: The higher concentration of CO₂ can make separation easier. This method can also reduce the formation of certain nitrogen oxides.
- Main Limitation: Producing oxygen requires additional energy and specialised equipment, increasing project costs.
4. Direct Air Capture (DAC)
Direct Air Capture removes CO₂ directly from the atmosphere rather than from industrial exhaust gases.
- How It Works: Large fans move air through special filters or chemical solutions that capture CO₂. Heat or other energy is then used to release the captured CO₂ so it can be collected for further use or storage.
- Key Advantage: DAC can remove CO₂ already present in the atmosphere, including emissions that are difficult to capture directly from their original sources. When combined with suitable long-term storage, it can help remove carbon dioxide from the atmosphere.
- Main Limitation: Atmospheric CO₂ is present at a very low concentration, approximately 0.04% by volume. Therefore, large volumes of air must be processed, making DAC energy-intensive and expensive.
Quick Comparison of Carbon Capture Technologies
| Technology | Where CO₂ Is Captured | Main Applications | Main Limitation |
|---|---|---|---|
| Post-combustion | After fuel combustion | Existing power plants, cement factories, and industrial boilers | High energy demand for solvent regeneration |
| Pre-combustion | Before the resulting fuel gas is burned | Hydrogen production, ammonia manufacturing, and gasification plants | Requires specialised equipment |
| Oxy-fuel combustion | During fuel combustion | Suitable for power plants and industrial facilities | Additional energy required to produce oxygen |
| Direct Air Capture (DAC) | Directly from the atmosphere | Removing CO₂ already present in the air | High energy requirements and cost |
Note: Actual performance and costs depend on the technology, plant design, operating conditions, and CO₂ concentration.
Which Carbon Capture Technology Is Best?
There is no single technology that is best for every project. The right choice depends on the type of facility, fuel used, CO₂ concentration, energy requirements, and project costs.
- Existing power plants: Post-combustion capture may be suitable when major changes to the combustion system need to be avoided.
- Hydrogen and ammonia production: Pre-combustion capture may be suitable for facilities designed around these processes.
- Specially designed plants: Oxy-fuel combustion may be considered where oxygen-based combustion is practical.
- Atmospheric carbon removal: Direct air capture is an option for removing CO₂ directly from the air.
Capturing CO₂ is only one part of the process. For Carbon Capture and Storage (CCS), the captured gas must also be transported to a suitable storage site and monitored to help ensure long-term containment.
CO₂ Storage Methods and Safety
After carbon dioxide (CO₂) is captured, processed, and transported, it can be injected into suitable underground geological formations for long-term storage. This process, known as geological carbon storage or sequestration, is a key part of Carbon Capture and Storage (CCS). Selecting a suitable CO₂ storage site requires detailed geological investigation and subsurface assessment. Read our guide to Geotechnical Drilling and Well-Program Planning to understand how site investigations help evaluate underground conditions.
CO₂ is commonly stored in deep geological formations, often at depths greater than 800 metres. At suitable underground temperatures and pressures, CO₂ exists as a dense fluid, allowing large quantities to be stored within the pore spaces of underground rocks.
Successful storage depends on suitable geology, reliable injection wells, pressure management, and long-term monitoring.
Main Methods of Geological CO₂ Storage
1. Deep Saline Formations
Deep saline formations are porous underground rock layers containing highly saline water, commonly called brine.
- Storage Potential: These formations offer substantial potential storage capacity because they are widely distributed underground.
- Engineering Focus: Engineers assess rock porosity, permeability, storage capacity, and the integrity of surrounding geological barriers before selecting a site.
2. Depleted Oil and Gas Reservoirs
Depleted oil and gas reservoirs are underground formations where commercial hydrocarbon production has significantly declined or ended.
- Storage Potential: These reservoirs may be suitable because their geological structures have retained oil and natural gas over long periods.
- Engineering Focus: Existing geological and production data can support storage assessment. However, old wells, reservoir pressure, and sealing integrity must be carefully evaluated.
3. Unmineable Coal Seams
Some deep coal formations that are unsuitable for mining may also store CO₂.
- Storage Potential: CO₂ can attach to coal surfaces through a process called adsorption. In some cases, this may also help release methane trapped within the coal.
- Engineering Focus: Coal swelling, permeability changes, and limited injection capacity can make this method technically challenging.
How Is CO₂ Trapped Underground?
Underground CO₂ storage relies on four main trapping mechanisms that help prevent the injected gas from returning to the atmosphere.
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| CO₂ can be retained underground through structural, residual, dissolution, and mineral trapping within suitable geological formations. |
1. Structural and Stratigraphic Trapping
CO₂ is retained beneath low-permeability rock layers known as caprock. These geological barriers, which may include shale or other sealing rocks, help prevent upward migration.
2. Residual Trapping
As CO₂ moves through the storage formation, small amounts become trapped within microscopic rock pores by capillary forces. This reduces the mobility of the injected CO₂.
3. Dissolution Trapping
Some CO₂ gradually dissolves into the saline water present in the storage formation. This can reduce the amount of mobile CO₂ and contribute to long-term containment.
4. Mineral Trapping
Dissolved CO₂ can react with certain minerals in the surrounding rock to form stable carbonate minerals. The rate and extent of this process depend on the geological formation and its chemical composition.
These trapping mechanisms can operate together, with their relative importance changing over time.
Is Underground CO₂ Storage Safe?
Geological CO₂ storage can provide long-term containment when storage sites are properly selected, engineered, operated, and monitored. However, potential risks must be identified and managed throughout the project.
The main safety considerations include:
- CO₂ Leakage: Poorly sealed wells, faults, or fractures may create pathways through which CO₂ could migrate outside the intended storage formation.
- Well Integrity: Injection wells require suitable materials, cementing, and corrosion protection to maintain their integrity during operation and after closure.
- Pressure Build-Up: CO₂ injection increases pressure within the storage formation. Operators must manage injection rates and pressures to reduce the risk of unwanted fracturing, fault movement, or induced seismicity.
- Groundwater Protection: Storage sites must be evaluated to prevent CO₂ or displaced saline water from affecting protected groundwater resources.
Appropriate geological barriers, well design, pressure control, and regulatory oversight are essential for reducing these risks.
Monitoring, Measurement, and Verification (MMV)
Monitoring, Measurement, and Verification (MMV) helps operators assess CO₂ movement, storage performance, and containment throughout the project lifecycle.
Common monitoring techniques include:
- Pressure and Temperature Monitoring: Measures conditions within injection wells and storage formations to identify unexpected changes.
- Seismic Surveys: Help track the distribution and movement of CO₂ underground where geological conditions support their use.
- Well Integrity Testing: Checks the condition of well barriers, casing, and cement to reduce leakage risks.
- Groundwater and Soil-Gas Monitoring: May be used to detect changes that could indicate CO₂ migration or impacts on protected groundwater.
- Satellite Monitoring: In some projects, satellite-based techniques can help detect surface movement associated with changes in underground pressure.
The monitoring programme is designed according to the storage site's geology, identified risks, operating conditions, and applicable regulations.
Overall, effective geological CO₂ storage requires careful site selection, reliable well construction, controlled injection, and appropriate long-term monitoring. These measures help support the safe and responsible operation of CCS projects.
Applications of CCS in Major Industries
Carbon Capture and Storage (CCS) can help reduce carbon dioxide (CO₂) emissions from industries where conventional methods such as energy efficiency, renewable electricity, and fuel switching may not be sufficient. These industries include cement, steel, oil and gas, power generation, hydrogen production, and chemicals.
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| CCS can help capture CO₂ emissions from power generation, steelmaking, cement production, refineries, and hydrogen facilities before transporting it for storage. |
1. Oil and Gas Industry
The oil and gas industry can use CCS to reduce emissions from natural gas processing, refineries, and hydrogen production facilities.
- CO₂ Capture: Natural gas processing plants often separate CO₂ from raw natural gas to meet product specifications. Refineries and hydrogen plants can also have significant sources of CO₂ emissions.
- Subsurface Expertise: The industry's experience in reservoir engineering, drilling, well construction, and pipeline operations can support the development of geological CO₂ storage projects.
- Enhanced Oil Recovery (EOR): Some oil fields use injected CO₂ to improve oil recovery. A portion of the injected CO₂ may remain underground, but the net climate benefit depends on the amount retained and the emissions associated with the additional oil produced and used.
2. Cement and Lime Manufacturing
Cement and lime production are important applications for CCS because their manufacturing processes release CO₂ through both fuel combustion and chemical reactions.
Process Emissions: During cement production, limestone is heated to produce lime, releasing CO₂ in a reaction that can be written as:
CaCO₃ → CaO + CO₂. This chemical process is called calcination. It generates emissions that cannot be eliminated simply by switching to renewable electricity.
- Role of CCS: Capture systems can separate CO₂ from kiln exhaust gases. Post-combustion capture and oxy-fuel technologies are among the approaches being developed for cement plants.
- Main Challenge: High capture costs, energy demand, and the need for suitable transport and storage infrastructure can affect project feasibility.
3. Iron and Steel Industry
Steel production can generate substantial CO₂ emissions, particularly when coal-based blast furnaces are used to produce iron.
- Emission Sources: Traditional blast furnace–basic oxygen furnace (BF-BOF) steelmaking uses coke as both a fuel and a reducing agent. This process produces CO₂-containing gases at different stages of production.
- Role of CCS: Carbon capture can be applied to suitable gas streams to reduce emissions from existing steelmaking facilities.
- Other Options: CCS may also complement natural gas-based direct reduced iron (DRI) production. Other emissions-reduction approaches include scrap recycling, electrification, and hydrogen-based ironmaking.
4. Thermal Power Generation
Coal- and natural gas-fired power plants release CO₂ when fuels are burned to generate electricity.
- Capture Process: Capture equipment separates CO₂ from exhaust gases before they are released into the atmosphere. Chemical solvents are one option for treating suitable flue gas streams.
- Energy Requirements: Capture equipment requires additional energy, often including steam for solvent regeneration. This reduces the net electricity a plant can deliver and can increase its operating costs.
- Potential Benefit: Some capture systems are designed to capture around 90% or more of the CO₂ in the treated gas stream under specified operating conditions. Actual performance varies by technology and plant design.
5. Hydrogen and Ammonia Production
Hydrogen and ammonia production can provide suitable opportunities for carbon capture, depending on the manufacturing process.
- Hydrogen Production: Conventional hydrogen production from natural gas can generate concentrated CO₂ streams during reforming and related processing steps.
- Capture Advantage: Capturing CO₂ from suitable concentrated streams can be less challenging than capturing dilute CO₂ from some power plant exhaust gases.
- Blue Hydrogen and Ammonia: When fossil fuels are used, and the associated CO₂ is captured and stored, the products are commonly described as blue hydrogen and blue ammonia. Their overall emissions depend on capture performance, energy use, upstream methane emissions, and CO₂ storage.
6. Chemicals and Petrochemicals
Chemical and petrochemical facilities produce CO₂ through fuel combustion and various industrial reactions. Some processes also generate concentrated CO₂ streams that may be suitable for capture.
- Potential Applications: Carbon capture may be relevant to selected facilities producing methanol, hydrogen, fertilisers, and other chemicals.
- Industrial Benefit: Capturing CO₂ from suitable process streams can reduce emissions, particularly when the gas is relatively concentrated.
- Main Challenge: Capture requirements vary across processes, and each project must be assessed for cost, energy use, and access to storage infrastructure.
Why Is CCS Important for Heavy Industry?
Heavy industries produce essential materials such as cement, steel, and chemicals. Some emissions come from fuel combustion, while others result directly from the chemical reactions used in manufacturing.
Different sectors therefore need different emissions-reduction strategies.
- Where practical: Energy efficiency, renewable electricity, electrification, and material recycling can reduce emissions.
- For process emissions: CCS can capture CO₂ that remains difficult to eliminate through other measures.
- For long-term storage: Suitable geological formations and reliable transport systems are required.
CCS is not a replacement for renewable energy or other decarbonisation measures. It is one of several options that can help reduce industrial emissions, particularly where other approaches cannot deliver sufficient reductions on their own.
Benefits and Challenges of Carbon Capture and Storage (CCS)
Carbon Capture and Storage (CCS) can help reduce carbon dioxide (CO₂) emissions from heavy industries and fossil-fuel-based facilities. It is particularly relevant where emissions are difficult to eliminate through energy efficiency, renewable energy, and electrification alone.
However, CCS also involves high costs, additional energy consumption, transportation requirements, and long-term storage responsibilities. Understanding both its benefits and limitations is essential when evaluating CCS projects.
Key Benefits of CCS
1. Reduces Industrial Process Emissions
Some industrial processes release CO₂ through chemical reactions, regardless of the fuel used to provide heat. For example, cement production releases CO₂ when limestone is converted into lime during clinker manufacturing.
CCS can capture these process emissions and help reduce the overall carbon footprint of industries such as cement, steel, and chemicals.
2. Supports Existing Industrial Facilities
Retrofitting suitable industrial facilities with carbon capture systems may help reduce emissions without completely replacing existing equipment. This can be valuable for plants with long operating lives and significant investment in infrastructure.
However, retrofitting is not always the most economical option. The decision depends on plant design, remaining operating life, capture costs, and available alternatives.
3. Enables Long-Term CO₂ Storage
Captured CO₂ can be injected into suitable deep geological formations, including saline formations and depleted oil and gas reservoirs.
Structural trapping, residual trapping, dissolution, and mineral trapping can all contribute to containment. Proper site selection, well integrity, pressure management, and monitoring are essential for long-term storage.
4. Supports Low-Carbon Hydrogen Production
CCS can reduce emissions from hydrogen production using fossil fuels. Hydrogen produced this way is commonly called blue hydrogen.
The overall climate benefit depends on the amount of CO₂ captured and stored, energy consumption, upstream methane emissions, and other lifecycle emissions.
5. Encourages Shared Industrial Infrastructure
Regional industrial clusters can connect multiple facilities to shared CO₂ pipelines, transport systems, and storage sites.
Sharing infrastructure may reduce costs for individual projects and support the development of larger carbon capture networks. However, these benefits depend on sufficient CO₂ volumes, suitable storage capacity, investment, and effective coordination.
Main Challenges of CCS
1. High Capital and Operating Costs
CCS requires specialised equipment for capturing, purifying, compressing, transporting, and storing CO₂. Operating costs include energy, maintenance, materials, monitoring, and storage management.
These costs can make projects difficult to finance, particularly where carbon pricing, financial incentives, or regulatory requirements do not adequately support investment.
2. Additional Energy Requirements
Carbon capture systems require extra energy, which can reduce overall plant efficiency.
- Thermal Energy: Some capture systems use steam or heat to release CO₂ from chemical solvents.
- Electrical Energy: Compressors and other equipment consume electricity to prepare CO₂ for transportation and storage.
The additional energy demand is known as the energy penalty. Its size depends on the capture technology, plant design, operating conditions, and CO₂ transport requirements.
3. Dependence on Transport and Storage Infrastructure
CCS depends on a connected system of capture equipment, transportation facilities, and approved storage sites. A delay or shutdown in one part of the system can affect the entire project.
Facilities therefore need reliable transport arrangements, suitable storage capacity, contingency plans, and clear operating procedures.
4. Geological and Well Integrity Risks
Geological storage requires careful management of potential risks.
- Leakage: Poorly sealed wells or unsuitable geological pathways may allow CO₂ to migrate outside the intended storage formation.
- Pressure Build-Up: Excessive injection pressure can affect geological formations and may increase the risk of fault movement or induced seismicity.
- Well Integrity: Injection and abandoned wells must be assessed to reduce the risk of leakage over time.
Appropriate site assessment, well construction, pressure control, and monitoring help manage these risks.
5. Incomplete Capture and Lifecycle Emissions
Carbon capture systems do not necessarily capture all the CO₂ produced by a facility. Their performance varies with technology and operating conditions.
The overall climate benefit must also account for emissions from energy use, fuel production, transportation, equipment manufacturing, and other parts of the project. For fossil-fuel-based systems, upstream methane emissions can also affect the results.
6. Long-Term Liability and Public Acceptance
CO₂ storage projects require clear rules governing monitoring, reporting, site closure, and responsibility for long-term storage.
Communities may also have concerns about pipelines, injection wells, groundwater protection, and potential leakage. Transparent risk assessments, regulatory oversight, and public engagement are important for building confidence.
Benefits and Challenges of CCS: Quick Comparison
| Area | Main Benefit | Main Challenge |
|---|---|---|
| Emissions reduction | Can capture industrial and process CO₂ emissions | Residual emissions and lifecycle impacts remain |
| Industrial facilities | May reduce emissions from existing plants | Retrofitting can be costly or technically difficult |
| Energy and efficiency | Supports emissions reduction in selected applications | Capture and compression require additional energy |
| CO₂ storage | Suitable formations can provide long-term containment | Requires careful site selection and monitoring |
| Industrial infrastructure | Shared networks may reduce project costs | Requires investment and coordination across facilities |
| Long-term operation | Can support industrial decarbonisation | Requires regulatory oversight and clear long-term responsibility |
Is CCS a Sustainable Solution?
CCS can contribute to climate change mitigation, particularly in industries where emissions are difficult to eliminate through other methods. However, it is not a universal solution and should not replace practical emissions-reduction measures.
Renewable energy, energy efficiency, electrification, material recycling, and alternative production methods remain important wherever they can reduce emissions effectively.
CCS can complement these approaches by capturing emissions that remain difficult to avoid. Its overall value depends on the amount of CO₂ captured and permanently stored, the energy required, the full lifecycle emissions, and the cost of achieving those reductions.
CCS in India and the Future Outlook
India needs to expand its industrial capacity, infrastructure, and energy supply while reducing greenhouse gas emissions. The country has committed to achieving net-zero emissions by 2070.
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| India's CCUS development could connect industrial CO₂ sources with suitable geological storage formations, subject to site assessment and infrastructure development. |
1. Key Industrial Sectors for CCS in India
Cement Industry
India is one of the world's largest cement producers. Cement manufacturing releases CO₂ both from fuel combustion and from the chemical conversion of limestone into clinker. Carbon capture could help reduce these process emissions, alongside energy efficiency, alternative fuels, and lower-carbon cement technologies.
Iron and Steel Industry
India's steel industry includes coal-based blast furnace production, which generates significant CO₂ emissions. CCS could capture emissions from suitable steelmaking processes while the industry also explores scrap recycling, energy efficiency, and hydrogen-based iron production.
Thermal Power Generation
Coal-fired power plants remain an important part of India's electricity system. Carbon capture could reduce emissions from selected plants, although additional energy consumption, installation costs, and access to storage infrastructure are major considerations.
Refineries, Petrochemicals, and Fertiliser Plants
Refineries and fertiliser plants can offer opportunities for CO₂ capture, particularly where hydrogen production or other industrial processes generate concentrated CO₂ streams. These facilities could be considered for early projects where capture and storage are technically and economically feasible.
2. India's CCUS Policy and Research Initiatives
India is increasing its focus on CCUS research, technology development, and industrial applications.
In December 2025, the Department of Science and Technology (DST) launched a national CCUS research and development roadmap. It highlights technology development, industrial demonstration projects, skilled workforce development, safety standards, and shared infrastructure.
The Union Budget 2026–27 also announced an outlay of ₹20,000 crore over five years to support CCUS technology development and deployment across five industrial sectors: power, steel, cement, refineries, and chemicals.
India has also supported research through specialised institutions, including National Centres of Excellence in Carbon Capture and Utilisation. These initiatives aim to improve capture technologies and help move promising research towards industrial applications.
Pilot projects are another important step. For example, NTPC's Vindhyachal facility has a commissioned flue-gas CO₂-to-methanol plant. Such projects can help demonstrate carbon capture and utilisation, although producing a CO₂-based product is different from permanently storing CO₂ underground.
3. India's Geological CO₂ Storage Potential
Long-term CCS deployment in India will depend on identifying suitable underground formations close to major industrial emission sources.
Potential storage options include:
- Deep saline formations: Underground rock formations containing highly saline water.
- Depleted oil and gas reservoirs: Geological formations that may be suitable for CO₂ injection after detailed assessment.
- Other suitable rock formations: Certain geological formations may offer additional storage opportunities, subject to site-specific research.
India's experience in drilling, reservoir engineering, and subsurface geology could support storage-site assessment and project development.
However, theoretical storage capacity does not automatically mean that a formation is ready for commercial use. Detailed geological studies, caprock assessment, abandoned-well evaluation, pressure modelling, and monitoring plans are required before a storage site can be approved.
4. Major Challenges to CCS Deployment in India
India will need to address several challenges before CCS can expand significantly.
- High Costs: Capture equipment, compression systems, pipelines, injection wells, and monitoring require substantial investment.
- Additional Energy Demand: Capturing and compressing CO₂ consumes energy and can reduce the net output of power plants or increase industrial operating costs.
- Transport Infrastructure: Pipelines or other transport systems must connect industrial facilities with suitable storage sites.
- Storage-Site Assessment: Geological formations need careful evaluation to establish their capacity, safety, and suitability for long-term storage.
- Regulation and Liability: Clear rules are needed for injection permits, monitoring, site closure, and long-term responsibility for stored CO₂.
- Project Financing: Industrial operators need viable business models and appropriate financial support to manage the cost and technical risks of early projects.
5. The Future of CCS in India: Industrial Clusters
One potential approach is to develop shared CCUS hubs in industrial regions. Instead of requiring every factory to build its own transport and storage network, several facilities could connect to shared infrastructure.
For example:
Cement Plant + Steel Plant + Refinery → Shared CO₂ Transport Network → Suitable Geological Storage Site
Industrial clusters could help combine CO₂ volumes, share infrastructure costs, and support the development of regional storage projects. Regions such as Gujarat, Odisha, and Andhra Pradesh may warrant assessment because of their industrial activity, although actual project locations must depend on verified storage capacity and transport feasibility.
The future of CCS in India will depend on whether research, policy support, and pilot projects can develop into technically reliable and economically viable operations.
CCS should complement renewable energy, energy efficiency, electrification, and material recycling—not replace them. Its greatest value will be in applications where it can deliver additional, measurable emissions reductions that are difficult to achieve through other methods alone.
Frequently Asked Questions (FAQs) About CCS
1. What Is Carbon Capture and Storage (CCS)?
Carbon Capture and Storage (CCS) is a technology that captures carbon dioxide (CO₂) from industrial facilities or power plants, transports it, and stores it in suitable underground geological formations to prevent its release into the atmosphere.
2. What Is the Difference Between CCS and CCUS?
CCS focuses on capturing CO₂ and storing it underground. CCUS stands for Carbon Capture, Utilisation and Storage and also includes using captured CO₂ in products or industrial processes. The climate benefit of CO₂ utilisation depends on the application and how long the carbon remains contained.
3. What Are the Main Types of Carbon Capture Technologies?
The four main approaches are post-combustion capture, pre-combustion capture, oxy-fuel combustion, and direct air capture (DAC). Each technology is suited to different emission sources and operating conditions.
4. Where Is Captured CO₂ Stored?
Captured CO₂ can be injected into suitable deep geological formations, including deep saline formations and depleted oil and gas reservoirs. A storage site must be assessed for capacity, geological integrity, and long-term containment.
5. Is Carbon Capture and Storage Safe?
CCS can provide long-term CO₂ storage when projects use suitable geological formations, reliable wells, controlled injection pressures, and appropriate monitoring. Potential risks, including leakage and groundwater impacts, must be assessed and managed.
6. Can CCS Remove CO₂ Directly from the Atmosphere?
Yes. Direct Air Capture (DAC) removes CO₂ from ambient air. When the captured CO₂ is stored durably, and the process has sufficiently low lifecycle emissions, DAC can contribute to net carbon dioxide removal.
7. Which Industries Can Benefit from CCS?
CCS may help reduce emissions from cement, steel, chemicals, oil and gas processing, hydrogen production, and selected power plants. Its suitability depends on the emission source, costs, energy requirements, and access to transport and storage infrastructure.
8. What Are the Main Challenges of CCS?
The main challenges include high investment costs, additional energy consumption, transport infrastructure requirements, storage-site assessment, and long-term monitoring. The overall climate benefit also depends on lifecycle emissions and the amount of CO₂ successfully stored.
9. What Is the Future of CCS in India?
India is exploring CCUS through research programmes, technology development, and industrial initiatives. Potential applications include cement, steel, refineries, chemicals, and power generation. Wider deployment will depend on project economics, suitable storage sites, infrastructure, and effective regulation.
10. Can CCS Help Achieve Net-Zero Emissions?
CCS can contribute to net-zero targets by reducing emissions that are difficult to eliminate through other methods. However, it needs to complement renewable energy, energy efficiency, electrification, and other emissions-reduction measures.
Conclusion
Carbon Capture and Storage (CCS) is an important engineering solution for reducing carbon dioxide (CO₂) emissions from heavy industries where conventional decarbonisation methods may not be sufficient. By capturing CO₂ at industrial facilities, preparing it for transportation, and storing it in suitable underground geological formations, CCS can help reduce emissions from cement, steel, thermal power generation, chemicals, and oil and gas operations.
However, its effectiveness depends on several factors, including capture costs, additional energy requirements, reliable transport infrastructure, suitable storage sites, and long-term monitoring. CCS is not a replacement for renewable energy, energy efficiency, material recycling, or direct electrification. Instead, it can complement these approaches by addressing residual emissions that are difficult to eliminate through other methods alone.
For India and the global energy industry, the next challenge is to turn research and pilot projects into technically reliable and economically viable commercial operations. Careful site assessment, transparent monitoring, appropriate regulation, and collaboration across industries will be essential to achieving meaningful emissions reductions and supporting the transition towards a lower-carbon future.
Explore Next: Understanding underground geological formations is important for evaluating potential CO₂ storage sites. Read our guide to Geotechnical Drilling: How to Plan & Implement a Well Program to learn more about drilling methods, site investigation, and subsurface evaluation.
