Carbon Capture and Storage (CCS) is an integrated suite of technologies that prevents large quantities of the greenhouse gas carbon dioxide (CO2) from being released into the atmosphere. Captured CO2 is then transported to a carefully selected and secure storage site, where it is injected deep into a rock formation for permanent storage.
Because CCS can achieve significant emission reductions, it is considered a key option within the portfolio of approaches required to reduce emissions.
Capturing and separating carbon dioxide (CO2) from the emission source is the first and most costly step in CCS. Post-combustion capture technologies are mature and relatively cost-effective for near-to-medium term CCS projects, while other capture systems are still in development and have exciting prospects.
Carbon capture can be applied to large-scale emissions processes, including coal and gas-fired power generation, natural gas processing, hydrogen, ethanol and fertilizer production, and the manufacture of industrial materials, such as cement, iron, steel, pulp and paper.
After CO2 is captured and separated from the emission source, it must be treated to remove contaminants and compressed before being transported. The gas is passed through compressors to meet pipeline specifications to pressures between 1,500 to 2,100 pounds per square inch (psi). Safely and reliably transporting CO2 from where it is captured to a storage site is a crucial stage in the CCS process. There are four options for the transportation of CO2: pipelines, ships, trucks and rail. Pipelines are — and are likely to continue to be — the most common method of transporting the large quantities of CO2 involved in CCS. Transport of CO2 by truck and rail is possible, but only for relatively small amounts. Given the large quantities of CO2 that would be captured via CCS in the long term, it is unlikely that truck and rail transport will be significant.
Storing carbon dioxide (CO2) emissions produced by various industries permanently removes this greenhouse gas from the atmosphere.
The most effective way to store CO2 is to inject it into an underground geological formation. The injection and storage of CO2 have been working safely and effectively for decades. Potential storage sites must be carefully selected to avoid geologic and subsurface hazards, such as faults and fractures.
Four key criteria are considered when selecting a storage site:
Not all rocks are suitable for the injection of CO2, but underground storage resources at our disposal are abundant. Oil and gas production is associated with the same types of geologic formations suitable for CO2 storage. Site selection and the design and operation of sophisticated injection and monitoring wells are critical for the permanent storage of CO2.