Carbon Capture and Geological Storage
Carbon capture and geological storage (CCS) is a technique for trapping carbon dioxide as it is emitted from large point sources, compressing it, and transporting it to a suitable storage site where it is injected into the ground. The technology of carbon capture and storage has significant potential as a mitigation technique for climate change, both within Europe and internationally, particularly in those countries with large reserves of fossil fuels and a fast-increasing energy demand. In the EU the CO2 emissions avoided through CCS in 2030 could account for some 15% of the reductions required.
How does CCS work?
Before carbon dioxide gas from power plants and other point sources can be stored, it must be captured as a relatively pure gas. This is not a new technology as CO2 is routinely separated and captured as a by-product from industrial processes. Captured CO2 needs to be stored (in compressed form) and transported to the place of sequestration.
CO2 can be sequestered directly in geological formations including oil and gas reservoirs, unmineable coal seams, and deep saline reservoirs. The security of sequestration depends on the site characteristics and management: the 2005 Special Report on CCS of the Intergovernmental Panel on Climate Change concluded that the fraction retained in appropriately selected and managed geological reservoirs is very likely to exceed 99% over 100 years and is likely to exceed 99% over 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 health or ecosystem risks.
Although the components of CCS are all known and deployed at commercial scale, integrated systems are new, and a clear regulatory framework is required. 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 uptake of CCS. Capture in particular is an expensive component. 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), and the energy needed to capture at such low concentrations imposes a significant efficiency penalty and thus additional cost.
Consultation on the way forward
In March 2013 the European Commission published a Consultative Communication on the future of CCS in Europe to stimulate debate on how best to promote its development.
The Communication identifies the barriers that have prevented CCS from progressing in Europe at the pace initially foreseen and discusses options for promoting its timely demonstration and early deployment and for strengthening the long-term business case for CCS. It invites stakeholders' views on the best policy framework for achieving this.
The responses to the consultation will feed into the Commission's work on the 2030 framework for EU climate and energy policies.