Climate Action

Carbon Capture and Geological Storage


Carbon capture and geological storage (CCS) is a technique for trapping carbon dioxide emitted from large point sources such as power plants, compressing it, and transporting it to a suitable storage site where it is injected into the ground. This technology has significant potential to help mitigate climate change both in Europe and internationally, particularly in countries with large reserves of fossil fuels and a fast-increasing energy demand.

How does CCS work?

Carbon capture theme photo

Before carbon dioxide gas from power plants and other point sources can be stored, it must be captured and stripped of most associated substances. This is not a new technology, as CO2 is routinely separated and captured as a by-product from industrial processes. Captured CO2 then needs to be stored (in compressed form) and transported to the place of sequestration.

CO2 can be stored in geological formations including oil and gas reservoirs, unmineable coal seams, and deep saline reservoirs. The 2005 Special Report on CCS by the Intergovernmental Panel on Climate Change concluded that appropriately selected and managed geological reservoirs are 'very likely' to retain over 99% of the sequestered CO2  for longer than 100 years and 'likely' to retain 99% of it for longer than 1000 years.

Ensuring safe and environmentally sound CCS

The environmental integrity of CCS is the Commission's overriding concern. This is partly a matter of ensuring that the CO2 captured and stored remains isolated from the atmosphere in the long term; and partly about ensuring that the capture, transport and storage elements do not present other risks to human health or ecosystems.

Although the components of CCS are all known and deployed at commercial scale, integrated systems are new. A clear regulatory framework is thus required, and the EU's CCS Directive provides this.

High cost a barrier to uptake

The cost of capture and storage remains an important barrier to the take-up of CCS. The capture component in particular is an expensive part of the process. As flue gas from coal or gas-fired power plants contains relatively low concentrations of CO2 (10-12% for coal and around 3-6% for gas), the amount of energy needed to capture the gas makes the process costly.

CCS under 2030 policy framework for climate and energy

The Commission's proposal for a 2030 climate and energy policy framework acknowledges the role of CCS in reaching the EU's long-term emissions reduction goal.

Significant emissions cuts are needed in the EU's energy and carbon-intensive industries. As theoretical limits of efficiency are being reached and process-related emissions are unavoidable in some sectors, CCS may be the only option available to reduce direct emissions from industrial processes on the scale needed in the longer term.

In the power sector, CCS could be a key technology for fossil fuel-based generation. It could help balance an electricity system with increasing shares of variable renewable energy.

To ensure that CCS can be deployed in the 2030 timeframe, increased R&D efforts and commercial demonstration are essential over the next decade. A supportive EU framework will be necessary through continued and strengthened use of auctioning revenues.


CCS Directive

Reports on the implementation of the CCS Directive

Consultative Communication on the future of CCS in Europe

Other documents

Environmental conventions:




Questions and Answers on the directive on the geological storage of carbon dioxide (December 2008)

What is carbon capture and storage?

Carbon capture and storage is a suite of technological processes which involve capturing carbon dioxide (CO2) from the gases discarded by industry and transporting and injecting it into geological formations.

The major application for carbon capture and storage (CCS) is in reducing CO2 emissions from power generation from fossil fuels, principally coal and gas. However, CCS can also be applied to CO2-intensive industries such as cement, iron and steel, petrochemicals, oil and gas processing and others. After capture, the CO2 is transported to a suitable geological formation where it is injected, with the aim of isolating it from the atmosphere for good.

There are storage options other than geological storage such as storage in the water column and mineral storage. Storage in the water column is considered to present a high environmental risk and the directive on the geological storage of CO2 bans it within the Union. Mineral storage is currently the subject of research. Developments will be kept under review.

How does geological storage work?

There are four main mechanisms to trap CO2 in geological formations.

  1. Structural trapping, which is the presence of an impermeable cap-rock which prevents CO2 from escaping from the outset.
  2. Residual CO2 trapping, where CO2 is trapped by capillary forces in the interstices of the rock formation, which develops about 10 years after injection.
  3. Solubility trapping, where the CO2 dissolves in the water found in the geological formation and sinks because CO2 dissolved in water is heavier than normal water. This becomes important between 10 and 100 years after injection.
  4. Mineral trapping happens when dissolved CO2 chemically reacts with the rock formation to produce minerals.

Why the need for CCS?

While energy efficiency and renewables are in the long term the most sustainable solutions both for security of supply and climate, global greenhouse gas emissions cannot be reduced by at least 50% by 2050, as they need to be, if we do not also use other options such as carbon capture and storage.

Timing is crucial. About a third of existing coal-fired power capacity in Europe will be replaced within the next 10 years. Internationally, the energy consumption of China, India, Brazil, South Africa and Mexico will lead to a major global demand increase, which is likely to be met in large part from fossil fuels. The capacity to deal with these very substantial potential emissions must urgently be developed.

Is CCS technically mature?

The separate elements of capture, transport and storage of carbon dioxide have all been demonstrated, but integrating them into a complete CCS process and bringing costs down remain a challenge.

The biggest CO2 storage projects that European companies are involved in are the Sleipner project in the North Sea (Statoil) and the In Salah project in Algeria (Statoil, BP and Sonatrach). Both projects involve stripping CO2 from natural gas – a process which is already carried out before the gas can be sold – and storing it in underground geological formations.

The Sleipner project was spurred on by the Norwegian tax on CO2 which was significantly higher than the cost per tonne of CO2 stored in the Sleipner geological formation. The In Salah project was triggered by BP's internal carbon trading system. Other demonstration projects underway are the Vattenfall project at Schwarze Pumpe in Germany and the Total CCS project in the Lacq basin in France.

The European Technology Platform on Zero Emission Fossil Fuel Power Plant (ETP-ZEP), a stakeholder initiative supported by the Commission, has identified some 15 full-scale demonstration projects that could go ahead once the necessary economic framework is in place.

How much will carbon capture and storage cost?

The cost of CCS involves partly capital investment on equipment to capture, transport and store CO2, and partly the cost of operating this equipment to store the CO2 in practice, such as the amount of energy required to capture, transport and inject the CO2. At current technology prices, up-front investment costs are about 30 to 70 % (i.e. several hundred million euros per plant) greater than for standard plants and operating costs are currently 25 to 75% greater than in non-CCS coal-fired plants. These costs are expected to substantially decrease as the technology is proven on a commercial scale.

Who will bear the cost?

The proposal to enable CCS will not impose additional costs over and above those required to meet the 20% greenhouse gas reduction target. Once CCS is mature, it will be for individual operators to decide whether to release emissions and pay ETS allowances to cover them or use CCS to reduce their emissions and their ETS liabilities. The maximum an operator will pay will be largely set by the carbon price: CCS will only be deployed if the cost per tonne of CO2 avoided is lower than the carbon price. In this respect the carbon price internalises the climate cost of CO2 emissions. Depending on the conditions in the market in question, operators may pass on a portion of the carbon cost to consumers. (See MEMOs on effort sharing and revised ETS proposal)

In the early phase, CCS demonstration projects will require additional finance on top of the incentive provided by the carbon market because the current cost of the technology is substantially higher than the carbon price. To catalyse this additional finance, decisive financial commitment from industry will be crucial and Member State support measures are also likely to play a major role.

In view of the importance of early demonstration of CCS in power generation and given that a number of those projects may require some public funding, the Commission is ready to view favourably the use of state aid for covering the additional costs related to CCS demonstration in power generation projects. This commitment is reflected in the revised Environmental State Aid Guidelines adopted on 23 January 2008.

The amended Emission Trading Directive foresees that Member States should use at least 50% of their auctioning revenues to finance the fight against climate change, including the environmentally safe capture and geological storage of CO2. In addition, up to 300 million allowances in the new entrants reserve of the revised EU ETS will be made available for the construction and operation of up to 12 commercial demonstration projects for the environmentally safe capture and geological storage of CO2 and innovative renewable energy technologies in the EU.

Will CCS be made mandatory?

Not at this stage. The directive enables carbon capture and storage by providing a framework to manage environmental risks and remove barriers in existing legislation. Whether CCS is taken up in practice will be determined by the carbon price and the cost of the technology. It will be up to each operator to decide whether it makes commercial sense to deploy CCS.

To avoid a lock-in of technology, Member States have to ensure that operators of all combustion plants with a rated electrical output of 300 megawatts or more for which the construction licence is granted after entry into force of the directive, have assessed whether 1) suitable storage sites are available, 2) transport facilities are technically and economically feasible and 3) it is technically and economically feasible to retrofit for CO2 capture (so-called capture-ready assessment). Where the assessment shows that these conditions are met, suitable space for the equipment necessary to capture and compress CO2 has to be set aside on the installation site.

This situation may evolve, however. To meet GHG reductions beyond 2020, the deployment of CCS will be essential, and by 2015 the technological options will be clearer. Where environmentally safe CCS, as well as its economic feasibility, have been sufficiently demonstrated, the review of the directive in 2015 will examine whether it is needed and practicable to establish mandatory requirements for emission performance standards for new large combustion installations generating electricity.

How will CCS be treated under the EU Emissions Trading System?

The ETS will provide the main incentive for CCS deployment. CO2 captured and safely stored according to the EU legal framework will be considered as not emitted under the ETS. In Phase II of the ETS (2008-12) CCS installations can be opted in. For Phase III (2013 onwards), under the amended Emissions Trading Directive, capture, transport and storage installations will be explicitly included in the ETS.

What type of sites will be selected and how?

There are two main kinds of geological formation that can be used for CO2 storage: depleted oil and gas fields, and saline aquifers (groundwater bodies whose salt content makes them unsuitable for drinking water or agriculture).

Site selection is the crucial stage in designing a storage project. Member States have the right to determine which areas of their territory are free to be used for CO2 storage. Where exploration is required to generate the necessary information, exploration permits must be issued on a non-discriminatory basis, valid for 2 years with the possibility of extension.

A detailed analysis of the potential site must be carried out according to criteria specified in Annex I of the directive, including modelling of the expected behaviour of CO2 following injection. The site can be used only if this analysis shows that under the proposed conditions of use there is no significant risk of leakage, and that no significant health or environmental impacts are likely to occur.

The initial analysis of the site is done by the potential operator, who then submits the documentation to the Member State competent authority in the permit application. The competent authority reviews the information and if it satisfied that the condition is met, issues a draft permit decision.

For the early storage projects the directive includes an additional safeguard. To ensure consistent application of the directive across Europe and promote public confidence in carbon capture and storage the draft permits may be reviewed by the Commission with the assistance of a scientific panel of technical experts. The Commission's opinion will be public, but the final permitting decision remains with the national competent authority according to the subsidiarity principle.

Will storage be allowed outside the EU?

The directive can only regulate storage within the European Union and (if it is incorporated into the EEA Agreement, as the Commission expects), the European Economic Area. CO2 stored in these regions in accordance with the directive will be considered as not having been emitted under the ETS. Storing CO2 emissions outside the European Union is not banned, but any emissions so stored will receive no credit under the ETS, thus providing little incentive to store carbon dioxide abroad.

What is the risk of leakage? What will happen if a site leaks CO2?

The risk of leakage will depend very much on the site in question. The IPCC Special Report on CCS concluded that:

'observations...suggest that the fraction of CO2 retained in appropriately selected and managed geological reservoirs is very likely to exceed 99% over 100 years and likely to exceed 99% over 1000 years'.

The key issue is thus the appropriate selection and management of sites. The requirements on site selection are designed to ensure that only sites with a minimal risk of leakage are chosen. The review of draft permit decisions by the Commission – assisted by an independent scientific panel – will provide additional confidence that the requirements will be implemented consistently across the EU.

A monitoring plan must be set up to verify that the injected CO2 is behaving as expected. If, despite the precautions taken in selecting a site, it does leak in practice, corrective measures must be taken to rectify the situation and return the site to a safe state. Emissions Trading Allowances must be surrendered for any leaked CO2, to compensate for the fact that the stored emissions were credited under the ETS as not emitted when they left the source. Finally, the requirements of the Environmental Liability Directive on repairing local damage to the environment will apply in the case of leakage.

Who will be responsible for inspecting CO2 storage sites?

The competent authority in Member States must ensure that inspections are carried out to verify that the provisions of the directive are observed. Routine inspections must be carried out at least once a year, involving examination of the injection and monitoring facilities and the full range of environmental effects from the storage complex. In addition, non-routine inspections must be carried out if any leakage has been notified, if the operator's annual report to the competent authority shows that the installation is not compliant with the directive, and if there is any other cause for concern.

How is the responsibility for the site ensured in the long term?

Geological storage will extend over much longer periods than the lifespan of an average commercial entity. Arrangements are needed to ensure the long-term stewardship of storage sites. The directive thus provides for sites to be transferred to Member State control in the long term. However, the polluter pays principle requires that the operator retain responsibility for a site while it presents a significant risk of leakage. Also, rules are needed to ensure that no distortion of competition arises from different Member State approaches. Under the directive a storage site shall be transferred to the state when 1) all available evidence indicates that the CO2 will be completely contained for the indefinite future, 2) a minimum period before transfer to be determined by the competent authority has elapsed, 3) a financial contribution for the post-transfer period covering at least the costs for monitoring for 30 years has been made and 4) the site has been sealed and the injection facilities have been removed. As this is the second key decision in the lifecycle of a storage site (the first being the decision to permit the site for use), a Commission review is foreseen at this stage too.