Carbon capture and storage
Carbon capture and storage (CCS) is the process to remove carbon dioxide, from waste gases produced in large-scale industrial processes and permanently store it underground.
Carbon capture and reducing emissions
Carbon capture and storage (CCS) is one proposal to reduce global Carbon Dioxide, CO2, emissions.
It is thought to be most applicable to reduce emissions from large-scale point sources, such as electricity generated from fossil fuels, and industrial processes including steel and cement production.
In New Zealand, the government has:
- co-ordinated research and policy steering groups
- supported research and development in New Zealand
- collaborated on international research and development
- monitored international developments.
The steps involved in CCS
There are 4 main steps involved in the CCS process: capture, transportation, injection and storage.
CO2 is captured from large, single point sources, such as electricity generation plants and industrial processing plants, such as cement or steel production. There are different ways to capture the CO2:
- Post-combustion capture where CO2 is captured after the fuel has been burned, as in a typical thermal electricity plant.
- Pre-combustion capture where the fuel source is oxidised to produce syngas which can then be used in a variety of processes.
- Oxyfuel combustion where thermal fuel is burned in pure oxygen, rather than air, to produce an emission stream of virtually pure CO2 and water vapour.
CO2 is moved by pipelines or ship from its source to a storage site.
CO2 is injected through drilled wells into suitable geological formations. Stringent assessment criteria would be applied to find suitable sites, covering aspects such as:
- onshore or offshore locations
- capping layers above the geological formation
- porosity and depth of the geological formation
- seismicity of the area
- any previous intensive exploration and drilling activity.
CO2 is stored long term in suitable geological formations such as:
- depleted oil and gas reservoirs
- coal seams that cannot be mined
- deep saline aquifers.
It is not yet possible to show if CO2 will behave as expected in storage sites. Moreover, CCS technology is very expensive.
Health and safety and environmental considerations will be important to any development – CCS projects are technically complex and are likely to cover large areas, either directly or indirectly.
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CCS in New Zealand
The rationale to adopt carbon capture and storage (CCS) technology in New Zealand is different from other countries.
Compared to other countries, New Zealand has relatively few point sources of CO2 emissions and a far higher renewable contribution to electricity generation. This means that CCS has limited potential to help New Zealand mitigate climate change.
New Zealand's international approach has been to support the uptake of CCS, in particular by countries that emit large amounts of CO2.
New Zealand's support for the international development of CCS does not prejudge any decision on whether or when CCS might be undertaken in New Zealand.
The New Zealand Productivity Commission’s inquiry into a low-emissions economy(external link) includes a section on CCS in New Zealand.
New Zealand CCS Partnership
The former New Zealand CCS Partnership (whose members included the former Ministry of Economic Development, the former Ministry of Science and Innovation, Solid Energy, and the Coal Association of New Zealand) released 2 reports on the implications of CCS development in New Zealand:
- CCS in New Zealand - Case studies for commercial scale plant: Final report 2010 [PDF 6.4MB](external link)
- CCS in New Zealand – Can carbon capture and storage deliver value to New Zealand? Summary report 2011 [PDF 510KB](external link)
Participation in international forums
A number of international partnerships and organisations are working to develop CCS technology and address legal and regulatory issues. New Zealand is a member of 2 such organisations: