Carbon capture and storage (CCS), commonly referred to as geologic carbon sequestration, involves extracting CO2 released into the atmosphere by power plants or industrial facilities and depositing it underground for long-term storage or conversion into products like concrete and chemicals.
CCS technologies typically involve injecting CO2 into depleted oil fields or saline aquifers; other uses do not provide an overall net climate benefit.
1. Capture
Carbon Capture and Storage (CCS), often known by its acronym CC&S, entails collecting greenhouse gases produced from coal power plants, energy intensive industries and other sources and permanently storing them underground. CCS may be combined with utilization (often called “use”) or sequestration; where CO2 is converted into products like concrete or chemicals before being stored underground permanently. Many global CCS, utilization and sequestration projects aim to demonstrate long-term underground storage as viable long-term options.
However, CCUS can have several drawbacks, including being energy intensive and producing harmful air pollution; locking into fossil fuel use; compounding harmful impacts for communities already bearing the brunt of emissions intensive facilities; as well as leading to carbon leakage – when CO2 extracted from the atmosphere is taken back out for use by fossil-dependent processes instead.
2. Compression
Compression refers to the reduction of volume by means of compression pumps or mechanical means, such as piston compressors.
Once captured, CO2 can be transported either for permanent sequestration (such as permanent geological storage) or used in processes like urea production or carbonation of cement and concrete production. Utilization transforms waste CO2 into an invaluable industrial stream while helping to reduce emissions to the atmosphere.
At present, geologic formations that can store CO2 safely underground include saline aquifers, depleted oil and gas reservoirs, unmineable coal areas, organic-rich shales and basalt. Every potential site undergoes careful characterization and testing to ensure that CO2 will be safely contained underground; once inside they’re also regularly monitored to make sure none leak back out into the atmosphere.
3. Transport
Transport involves the movement of goods, services, people and information across long distances. Transport plays an integral part in today’s economy from workers traveling to work to consumers buying products online – but at what cost?
Transport of CO2 between emission sources and storage or utilization sites occurs through pipelines, ships and trains – an essential element of carbon capture and storage (CCS), which enables its deployment across global scale applications while meeting climate targets.
To safely transport CO2, it must first be chilled and compressed into liquid form before being transported through pipelines to storage sites – which could include former oil and gas reservoirs or coal beds – according to regional factors and project scale. The cost of such transportation systems varies according to their region or project scale.
4. Injection
Carbon Capture, Utilization and Storage (CCUS) refers to the process by which captured CO2 is transported via pipeline, ship, rail or road tanker to an authorized geological storage site for underground sequestration – known as Carbon Capture Utilisation and Storage.
At the injection site, compressed CO2 is injected into deep geologic formations such as depleted oil and gas reservoirs, coalbeds or saline aquifers using solubility trapping technology – using water mixed with physical properties of rock layers to capture CO2.
Snohvit’s early switch in storage site shows how projects must remain flexible in response to geological uncertainties, while at the same time providing evidence of why CCS will require significant expansion for meeting climate targets over the long-term.
5. Storage
Carbon capture and storage (CCS) technology aims to stop emissions of CO2 from power plants and other industrial processes from polluting the atmosphere, by collecting, transporting and storing it underground permanently in geological formations.
CO2 is compressed and transported to its storage site through pipeline or ship, where it is then injected into underground geological formations such as used up oil and gas reservoirs or unmineable coal seams with large volumes of porous rock that is covered by impermeable layers of seal rock – these geological features serve as ideal reservoirs.
CO2 injected into rocks is then “trapped” or “structurally trapped,” through a process known as pressure relief, becoming part of carbon capture storage (CCS) technology and expected to remain underground for millions of years.