CCS technology can trap carbon dioxide emissions so they can be stored to prevent them reaching the atmosphere, but as yet the method has not been used at scale.
Carbon capture and storage (CCS) is a proposal for mitigating climate change.
The idea is to capture carbon dioxide from major sources such as coal-fired power stations and industry and then store it underground or beneath the sea-floor so it cannot reach the atmosphere.
Large spaces would be needed to store enough carbon dioxide for CCS to have real benefits but there are large enough geological formations and old oil and gas fields that could be used.
A power plant with CCS could reduce carbon dioxide emissions by up to 90 percent. But this would also require more energy, which would raise the price of electricity the plant produces by 35-85 percent, according to the Intergovernmental Panel on Climate Change (IPCC).
The IPCC says that by 2050 the amount of carbon dioxide captured could represent 21-45 percent of all carbon dioxide emissions from human activities. So far, however, the technology has not been scaled up beyond pilot projects and most of these are in just a few countries.
CCS involves first separating the carbon dioxide from other gases and then purifying and compressing it for transport and storage. Carbon dioxide can be transported through pipelines or in liquid form in ships.
The costs of CCS will depend on which technological approach it used, where the carbon dioxide is stored and how far it must be transported.
The term CCS can also be used to describe biological processes, such as those that capture carbon dioxide and use it to grow algae that can be used to make animal feed or other products. This can be termed ‘Bio CCS’. Biochar is also sometimes considered to be a form of CCS.
Critics of CCS — such as the environmental organization Greenpeace — say that the coal industry is promoting it out of economic self-interest to justify building new new coal-fired power plants.
Greenpeace adds that CCS would not be ready in time to prevent dangerous climate change, and that there is no guarantee that the technology could be retro-fitted to existing power stations.
Specific concerns that NGOs, researchers and some governments have raised about CCS focus on its feasibility, cost and safety. There are concerns, for instance, that carbon dioxide could leak from where it is stored and get into the atmosphere.
Fears that carbon dioxide injected into the deep ocean could cause environmental harm mean that this form of storage is no longer considered a viable option.
One storyline that is set to develop is whether or not CCS will be included formally in a global deal to tackle climate change under the UN Framework Convention on Climate Change and its Kyoto Protocol.
Several countries oppose the inclusion of CCS in the Kyoto Protocol’s Clean Development Mechanism as it is costly and has many technical challenges while others — such as Norway, Australia — have supported it.
IISD’s Earth Negotiations Bulletin will publish daily updates during meetings where these negotiations take place, and the Climate Change Media Partnership’s roster of experts includes CCS specialists who are willing to talk to journalists.
The Guardian newspaper’s website has a good collection of news articles, background information and other resources on CCS that provide a rich source of story ideas.
CASE STUDY – CCS in China
China is now the world’s number one emitter of carbon dioxide and the nation’s dependence on highly-polluting coal-fired power stations is still growing, which adds to the challenge of addressing global climate change.
European and Chinese scientists are working together to develop CCS projects in parts of onshore north-east China in three projects known as COACH (Cooperation Action within Carbon Capture and Storage China-EU), NZEC (Near Zero Emissions from Coal) and GeoCapacity.
They are investigating the potential for geological storage of carbon dioxide to map the space available in old or depleting oil fields, naturally occurring underground saltwater, and areas of sandstone that contain coal that cannot be mined.
The researchers have encountered challenges. They found that underground reservoirs of porous rocks have numerous faults that could create technical challenges. The areas of underground saltwater were vast – meaning that large amounts of carbon dioxide could be stored there, but it was not clear whether it could also leak out and find its way to the atmosphere.
Phase 1 of the NZEC project has explored options for demonstration and build capacity for CCS in China. Phase 2 will carry out further development work on storage and capture options leading to Phase 3, which will construct a demonstration plant by 2015. For more information, see the NZEC website.
False Hope, a Greenpeace International report on CCS (PDF)
Intergovernmental Panel on Climate Change special report on CCS – Summary for Policymakers – Full report (PDF)
Interactive map of major CCS sites (planned or operational) worldwide
Exploring the media framing of carbon capture and storage and its influence on public perceptions [PDF]