The CCS Browser has been created by the CO₂ Capture Project to help you learn more about CO₂ capture and storage, or CCS as it's commonly known.

PROCESS

How does CCS work?

See how CCS is already being used to reduce industrial emissions by capturing, transporting and then storing CO₂ underground

STORAGE

How is CO₂ stored securely?

Take a look deep underground to see some of the differences between rock types and how CO₂ is trapped deep in the subsurface

TECHNIQUES

How do we ensure CCS works?

Learn about the procedures and technologies used to plan, run and monitor a CO₂ storage operation

TARGETS

What difference can CCS make?

See estimates of how much captured CO₂ could be stored underground and where

How does CCS work?

Around 40% of global CO₂ emissions come from industry. CO₂ capture and storage (CCS) can prevent up to 90% of industrial CO₂ emissions from reaching the atmosphere. The CO₂ emitted by industries such as electricity production, cement manufacture and oil and gas refining can be captured at source, transported, then stored safely and permanently, deep underground. Many of the technologies for CCS already exist and have been used in other industrial processes for many years. A number of large-scale CCS projects are already in operation across the world. The challenge now is to develop CCS for extended large-scale use in power generation and heavy industry.

Capture

For decades, CO₂ has been captured from emitting sources and sold for use by other industries, such as soft drink manufacturers. Existing capture technologies can be applied to large-scale industrial processes, such as power generation, oil and gas production and cement manufacture. Capturing CO₂ requires extra energy, but even taking this into account, the cost efficiency of CCS is still better than most forms of low-carbon energy generation. The main technical challenges now are to continue to address this 'energy penalty' and reduce operating costs. Three main technologies exist: post-combustion; pre-combustion and oxyfiring.

Capture

Pre-combustion

Pre-combustion uses steam and air or oxygen to convert fuel into a mixture of mainly hydrogen and CO₂. The CO₂ is separated using liquid solvents or solid adsorbents while the hydrogen can then be burned without producing further CO₂ or used in refinery processes to create cleaner fuels. The pressure and concentration of CO₂ obtained through pre-combustion is relatively high, making separation easier to achieve. Pre-combustion has been used for many years in the industrial production of ammonia and hydrogen. However, the fuel conversion steps required are relatively complex, making pre-combustion more suitable for use in new-build plants rather than retrofitting to existing plants.

Capture

Oxyfiring

Oxyfiring involves burning fuel in pure oxygen rather than air. This results in an exhaust gas made up largely of CO₂ and water vapour. Cooling and compressing this gas stream removes the water vapour and separates out the CO₂. A final purification may be needed, depending on the level of impurities in the CO₂. One of the benefits of oxyfiring is that very high CO₂ capture rates (over 98%) are feasible. The energy penalty in this case is related to the preparation of pure oxygen by air separation. Oxyfiring can be used in new builds and potentially retrofitted to existing plants.

	INTRODUCTION
	POST-COMBUSTION
	PRE-COMBUSTION
	OXYFIRING

	INTRODUCTION
	CO₂ COMPRESSION
	INFRASTRUCTURE

	INTRODUCTION
	ENHANCED OIL RECOVERY
	NATURAL GAS PARALLELS

CAPTURE TECHNOLOGIES

SUBSURFACE STUDIES

MONITORING FIELD TRIALS

CO₂ capture from industrial processes such as power generation involves using additional energy – between 10 and 40% depending on the type of plant. Reducing this energy penalty to make CCS more efficient is a major focus for technologists. Despite this penalty the resulting efficiency, in terms of cost, still remains higher than for most low-carbon energy generation methods.

Amines are organic compounds used in some capture processes. Some amines are well known as potentially hazardous to health – with carcinogenicity being one such effect. However, the amines used for CO₂ capture have not been shown to be carcinogenic and would have only a mildly adverse effect on human health should they be accidentally released.

Safety is paramount and safeguards, including careful monitoring and strict regulations have been built up over many years of pipeline experience to ensure safety and minimise incidents. In the few instances of documented leaks from wells and pipelines, they have been readily contained and repaired without damage to the environment or human health.

CO₂ itself is a natural part of the biosphere and life depends upon it. It is not explosive, neither is it flammable. In fact it extinguishes flames and is frequently used in fire extinguishers for this purpose. In high concentrations it is a hazard to humans, affecting the respiratory system and, in severe cases, it can be fatal. Substantial loss of CO₂ from a CCS pipeline or storage zone into the atmosphere, while highly unlikely, may cause temporary hazards.

Constructing and managing pipelines can be expensive. However, pipelining from CCS 'clusters' could significantly improve the economics of CO₂ transportation. Such clusters - areas where CO₂-intensive industries are concentrated near to one another - would be able to share the same pipeline infrastructure. A good example of this can be seen in North East of England, where planning is underway to maximize a concentration of existing and planned power plants and industrial sources in East Yorkshire and Humberside through a shared pipeline network leading to adjacent potential storage fields under the North Sea.

There is very high confidence that essentially all stored CO₂ will remain permanently trapped in carefully selected and operated storage formations, which feature natural boundaries to CO₂ and other fluid (e.g. brines) movement, including overlying impermeable rock strata. Natural trapping processes also ensure that the CO₂ remains trapped securely and indefinitely.

CCS projects around the world have not reported significant ‘induced seismicity’. It is important to distinguish between the commonly used term ‘earthquake’ and non-damaging ‘seismicity’. Seismic events of less than 3.0 magnitude on the Richter Scale are generally not felt by people, cause no damage to buildings and are extremely common. They release around 60 times less energy than the magnitude 5.0 earthquakes that are detectable by humans. Many subsurface operations do cause measurable induced microseismicity but these are rarely felt or able to cause damage. A typical CO₂ storage site will have been assessed for‘geomechanical’ stability. This will predict the safe range of operation for the project. Much can be done in the development of a CO₂ storage field to prevent pressure build up including changing injection rates, drilling new injection wells elsewhere in the reservoir or withdrawing brine and injecting it into another reservoir.

CCS currently represents an additional and high cost, particularly in existing petroleum refineries with little to no room for expansion, and in power generation from fossil fuels. Its use in chemical and gas processing represents lower cost opportunities and there is also significant value in capturing CO₂ for use in Enhanced Oil Recovery. Without CCS, the IEA estimates that the overall cost of reducing CO₂ emissions would rise by around 70%. Capture is estimated to account for 75-80% of the total cost of CCS. Next generation capture technologies are being developed that will lower costs and widespread implementation of CCS should bring costs down further through economies of scale. However, for CCS to be a commercially viable venture long term, a policy framework that gives value to carbon must be in place, in order for a more stable price for carbon to be set by the market.

The technologies and knowledge to carry out the different components of CCS largely exist already, although there are some gaps in knowledge that need to be addressed, including reducing the cost and energy penalty associated with capture. Over 60 large-scale industrial CCS projects have been identified globally, with 21 in operation or under construction (GCCSI: Global Status of CCS, February 2014). However, it is true that fully integrated CCS (i.e. capture, transportation and storage) has not yet been demonstrated on an industrial-scale power station.

This is still an emerging area. Responsibility for long-term, post-closure monitoring and safety and legal liability for local and global environmental impact, potential intervention and payment of damages are being discussed and developed in different countries, regions and jurisdictions across the world. The state of development differs from country to country. Further information can be found in CCP's reviews of regulatory issues, available at www.co2captureproject.org/reports.

Even at the most conservative estimates, it is believed by bodies such as the IEA and IPCC that there is storage capacity far in excess of what is needed to store predicted CO₂ emissions over at least the next 100 years. Although estimates vary of the upper limit of storage potential, there is much greater certainty around these lower limits, which would in themselves provide ample storage space. In general, government and other surveys show a good correlation between the areas where emissions come from and the areas where major geological storage options are most plentiful.

Robust regulatory frameworks for CCS are important in helping with the successful planning, development and implementation of CCS projects. Such frameworks cover areas such as capture and transport, storage property rights and monitoring, long term liability and Enhanced Oil Recovery. Their state of development differs from country to country. CCP has published a review of selected regulatory issues, available at www.co2captureproject.org/reports.

How is CO₂ stored securely?

Fluids such as water and oil, and gases such as CO₂ and methane have accumulated in the Earth's sedimentary crust for over a billion years. The natural structures and processes that keep them 'trapped' are well understood and form the basis of how CO₂ can be permanently stored at depths of greater than 800 metres (2600 feet) in a dense, near-liquid form. The geological make-up of the storage zone and the natural trapping processes that keep the CO₂ in place are explained in this section as well as the types of site which are most suitable. Regulatory controls and ongoing monitoring provide further reassurance that the CO₂ will remain safely stored.

CO₂ Trapping

Once injected into the storage zone, there are several natural trapping processes that ensure the CO₂ stays securely underground and will not leak to the surface or into groundwater. These involve a combination of physical and chemical processes and take place simultaneously and sequentially over a range of time from years to tens of thousands of years.

	INTRODUCTION
	CAPACITY
	CONTAINMENT

	INTRODUCTION
	STRUCTURAL
	RESIDUAL
	DISSOLUTION
	MINERAL

	INTRODUCTION
	DEEP SALINE RESERVOIRS
	DEPLETED OIL & GAS RESERVOIRS

SUBSURFACE STUDIES

Storage

There is very high confidence that essentially all stored CO₂ will remain permanently trapped in carefully selected storage formations, which feature natural boundaries to CO₂ and other fluid (e.g. brines) movement, including overlying impermeable rock strata. Natural trapping processes also ensure that the CO₂ remains trapped securely and indefinitely.

CCS projects around the world have not reported significant 'induced seismicity' – the movement of rocks due to pressure increase from subsurface operations. It is important to distinguish between the commonly used term 'earthquake' and microseismicity. Microseismicity ('earthquakes' less than magnitude 3) are extremely common in all parts of the world. Many subsurface operations do cause measurable induced microseismicity but these are rarely felt or able to cause damage. A typical CO₂ storage site will have been assessed for 'geomechanical' stability. This will predict the safe range of operation for the project. Much can be done in the development of a CO₂ storage field to prevent pressure build up that could lead to induced seismicity. Pressure anomalies detected during operations can be remedied by changing injection rates, drilling new injection wells elsewhere in the reservoir or even by withdrawing brine and injecting it into another reservoir.

Robust regulatory frameworks for CCS are important in helping with the successful planning, development and implementation of CCS projects. Such frameworks cover areas such as capture and transport, storage property rights and monitoring, long-term liability and Enhanced Oil Recovery. Their state of development differs from country to country. CCP has published a review of selected regulatory issues, available at www.co2captureproject.org/reports.

How do we ensure CCS works?

Established technologies and techniques, many adapted from use in the oil and gas industry, are already being used to store millions of tonnes of CO₂. Formalized operational procedures have been developed by a number of organizations while governments and regulators are also developing specific regulations to guide the selection and management process for CO₂ storage. Ongoing research and development from industry and scientists continues to build knowledge and understanding.

	INTRODUCTION
	TOOLS

	INTRODUCTION
	WELL CONSTRUCTION
	SURFACE MONITORING
	WELL MONITORING
	SEISMIC SURVEYS

MONITORING FIELD TRIAL

What difference can CCS make?

To meet the challenge of reducing CO₂ emissions, a combination of renewable energies, lower CO₂-emitting energy sources (such as natural gas or nuclear), CCS and energy efficiency is needed. The International Energy Agency (IEA) has produced a roadmap for reducing greenhouse gas emissions by 50% by 2050 to keep temperature rises to no more than 2°C. To meet this target, CCS will need to eventually deliver 17% of the necessary reductions. Just over half of this will come from electricity generation, just under half from industrial applications.

CCS Targets

To meet the IEA’s 2050 targets for CO₂ reductions through CCS, a rapid development of CCS projects worldwide is required. The technologies and knowledge for CCS development exist and some large-scale projects are already in operation, under development or planned but progress in commercializing CCS has slowed in recent years. CCS must be included in international climate change agreements; already CCS is accepted into the UN Clean Development Mechanism. A consistent regulatory framework and policy framework are also needed to encourage business to invest in CCS.

Storage Capacity

To meet the 2050 International Energy Agency (IEA) reduction targets for CCS, there will need to be sufficient space worldwide to store a cumulative total of 120 gigatonnes of CO₂. There is more than enough space to do this in deep saline reservoirs and depleted hydrocarbon reservoirs, often found close to concentrations of industrial emissions. Although there is some uncertainty about how much storage space in total is available worldwide, current best estimates of viable capacity are set at around 10% of theoretical capacity. As the map shows, even at these levels, there is more than enough space to store the CO₂ reductions needed by 2050.

Prospective Areas

Suitable rock formations for CO₂ storage exist all over the world, offshore and onshore, in the form of deep saline formations, depleted oil and gas reservoirs and coal beds. This map is a guide to the distribution of these 'prospective' areas. Shading shows highly prospective (most likely) and prospective areas. In addition, concentrations of industrial emission areas are also shown, revealing the relatively close proximity of these to likely storage zones.

Live Projects

A number of large-scale CCS projects exist - capturing and storing millions of tonnes of CO₂ annually. Many more are planned. In particular the oil and gas industry has been operating several geological CO₂ projects for a number of years. These have helped build understanding of implementing projects in different geological environments and importantly they have demonstrated that secure storage of large quantities of CO₂ is possible.

Explore the map to find out more about projects around the world.

Useful Resources

Further information about climate change, energy use and CCS is available from a range of organizations. The websites for these organizations are listed to provide further context to the contents of the CCS Browser.

CCP

Detailed information, factsheets, reports and presentations on the CCP's work
Developing CO₂ capture technologies and building scientific understanding of CO₂ storage

Specific information on storage site selection, wells, monitoring and operations is contained in
A Technical Basis for Carbon Dioxide Storage

An at-scale representation of CO₂ storage at 3000m (10,000 feet) Interactive 'In Depth' Tool

Intergovernmental Panel on Climate Change (IPCC)

Information on climate change including detailed temperature, emissions and impacts data as well as special reports on CCS
www.ipcc.ch

International Energy Agency (IEA)

CO₂ mitigation technologies explained, including a focus on CCS, with background, challenges and emissions reduction targets
www.iea.org

National Oceanic and Atmospheric Administration (NOAA)

Forecasts and historical global and US temperature data, reports and studies
www.noaa.gov

National Aeronautics and Space Administration (NASA)

Global climate change data, causes and effects explained
www.climate.nasa.gov/

The Bellona Foundation

Information on climate change causes and effects and on a range of mitigation solutions, including CCS
www.bellona.org

UN Department of Economic and Social Affairs, Population Division

Data and trends on global population growth and development
www.un.org/esa/population

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PROCESS

How does CCS work?

STORAGE

How is CO2 stored securely?

TECHNIQUES

How do we ensure CCS works?

TARGETS

What difference can CCS make?

How does CCS work?

Capture

Capture

Post-combustion

Capture

Pre-combustion

Capture

Oxyfiring

Transport

Transport

CO2 Compression

Transport

Infrastructure

Storage

Storage

Enhanced Oil Recovery

Storage

Natural gas parallels

CCP Projects

FAQ

Capture Demonstration

CO2 Behaviour Underground

CO2 Monitoring Technology

Capture

Transport

Storage

How is CO2 stored securely?

The Storage Zone

The Storage Zone

Capacity

The Storage Zone

Containment

CO2 Trapping

CO2 Trapping

Structural Trapping

CO2 Trapping

Residual Trapping

CO2 Trapping

Dissolution Trapping

CO2 Trapping

Mineral Trapping

Suitable Sites

Suitable Sites

Deep Saline Reservoirs

Suitable Sites

Depleted Oil and Gas Reservoirs

FAQ

CCP Projects

CO2 Behaviour Underground

Storage

How do we ensure CCS works?

Site Screening

Site Assessment

How is CO₂ stored securely?

CO₂ Compression

CO₂ Behaviour Underground

CO₂ Monitoring Technology

How is CO₂ stored securely?

CO₂ Trapping

CO₂ Trapping

CO₂ Trapping

CO₂ Trapping

CO₂ Trapping

CO₂ Behaviour Underground

CO₂ Monitoring Technology