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?
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.