Carbon Capture and Storage (CCS) refers to capturing emissions from large industrial facilities like refineries, coal and gas power plants, steel mills, and cement factories before they reach the atmosphere. CCS then transports them underground where they will be permanently stored within geological formations for long-term isolation.
CO2 can be injected into geological formations with suitable physical properties, such as deep saline aquifers or depleted oil and gas reservoirs.
Capture
CCS can help reduce emissions from fossil fuel power plants by sequestering CO2. Furthermore, it can be applied in energy-intensive industrial processes such as cement and steel production as well as transport emissions reduction efforts.
At present, most facilities with CCS use post-combustion capture, which uses solvent to flush flue gases of unavoidable emissions produced during normal combustion. Other methods for CCS capture include pre-combustion capture (using oxyfuel technology) or direct air capture, in which CO2 from the atmosphere itself is removed by means of this process.
Captured carbon dioxide is compressed into liquid form and transported by pipeline or special cargo ships to its chosen storage site, usually deep geological formations like depleted oil and gas reservoirs or coalbeds that have been drilled for decades. There is ample evidence that such underground formations can safely hold CO2 for decades at a time – providing high emitting nations with an effective long-term mitigation solution.
Transport
Carbon capture and storage (CCS) technology is at the core of meeting climate targets in countries worldwide. By reducing emissions from power plants and industrial facilities and safely and permanently storing their emissions underground, CCS allows nations to meet their climate goals more easily.
CO2 gas must then be transported from its capture site to a geological storage site via pipeline, truck, or ship. Pipelines work on the principle that liquids and gases move from areas of high pressure to low pressure; so captured CO2 must first be compressed down before being compressed for transport by pipelines or trucks or ships.
Post-combustion carbon capture and storage (CCS) is most often employed in coal-fired power generation. Fuel is gasified to form synthesis gas (or syngas), which contains both carbon dioxide and hydrogen. After separation using a physical solvent, CO2 is then injected underground in well-characterized storage formations such as saline aquifers or depleted oil and gas reservoirs for storage.
CO2 usage (sometimes called carbon utilization or utilization) involves using carbon dioxide that has been captured to produce tangible benefits such as enhanced oil recovery or building materials production, but this does not provide as many net climate benefits as dedicated carbon storage solutions.
Injection
CO2 captured at power plants is transported to an approved geological storage site where it will be permanently isolated in deep rock layers for permanent isolation, similar to how enhanced oil recovery operations use geologic formations for their enhanced oil recovery operations. Geologic formations have safely stored liquids and pressured gases for hundreds of millions of years without incident or incidental release into the environment.
As CCS requires significant amounts of energy, plants with CCS often burn additional fossil fuels – increasing emissions, worsening air quality, and delaying transition towards clean renewable sources of power.
Transporting and injecting CO2 underground poses risks of leaks that can pollute drinking water supplies, pollute land, cause earthquakes and create dense clouds which block roads, hinder evacuation plans and asphyxiate people – which many communities oppose. The Environmental Protection Agency’s Class VI underground injection requirements offer essential protection.
Storage
Carbon Capture and Storage (CCUS) involves collecting greenhouse gas emissions from power stations, industrial facilities or directly from the atmosphere and permanently storing them underground.
CO2 collected through capture is stored permanently within deep geological formations such as depleted oil and gas reservoirs, non-mineable coal beds or deep saline aquifers – sites which offer very high pressure storage solutions for CO2.
Scientists are exploring methods that utilize captured carbon dioxide as fuel or plastics. While this approach reduces emissions and provides indirect climate benefits, such as reduced production costs. This process, known as usage or utilization, does not directly reduce emissions or provide any net climate benefits once indirect effects are considered.
Transporting and storing CO2 requires an intricate system of dangerous pipelines with leakage risks that could compromise drinking water supplies or trigger earthquakes. Furthermore, injecting it deep underground poses additional threats – one recent leakage event caused evacuations and illnesses in rural Yazoo County Mississippi.