Carbon capture and storage (CCS) is an essential strategy for mitigating fossil fuel emissions. CCS involves extracting CO2 from power plants and industrial facilities before transporting it underground storage facilities and permanently depositing it there.
Captured CO2 is stored underground, typically within existing oil and natural gas fields. Commercial-scale CCS projects have already started, such as those being implemented by:
Capture
Carbon Capture and Storage (CCS) technology is used to reduce emissions from power plants and other energy-intensive industrial processes by capturing and storing carbon dioxide before it enters the atmosphere. CCS works by collecting flue gas from fossil fuel-powered plants, transporting it underground for geologic storage facilities, then permanently burying it underground.
Current commercial-scale CCS projects around the world number 26. Each uses various technologies to separate CO2 from flue gas streams and compress it into liquid form before injecting it deep underground geologic formations.
Some CCS projects store captured CO2 in an underground repository while others utilize it for enhanced oil recovery (EOR), wherein CO2 injection makes crude oil extraction simpler and cheaper. Other projects convert captured CO2 to useful products like building materials or chemicals with significant demand, making CCS even more appealing than before.
Compression
Carbon Capture and Storage (CCS) technology entails the separation of CO2 at power plants or industrial facilities, transport via pipeline to storage sites and injection into stable geological formations underground for permanent disposal. CCS technology will play an essential part in meeting long-term climate targets.
Presently, pulverized coal-fired power plants equipped with amine-based carbon capture technologies consume significant energy to compress captured CO2 to its supercritical liquid state for transport and storage purposes. Unfortunately, cost prediction models often underestimate this energy requirement, often including it as part of power plant efficiency penalties or presuming it will come from the grid.
CO2 is a heavy and viscous fluid with twice the molecular weight of natural gas and 22 times that of hydrogen, making it relatively straightforward from a thermodynamic perspective to compress but it presents unique challenges that must be met efficiently for efficient pumping operations.
Transport
CO2 captured from emissions is compressed and chilled before being transported via pipelines (or ships, trains or trucks) to its storage site. Energy is required to compress and maintain extremely low temperatures – one of the key cost components associated with CCS which varies based on location.
Once at its storage site, CO2 is injected into deep geologic formations for long-term storage. CO2 may be stored in depleted oil and gas reservoirs or saline aquifers which have the capacity to hold large volumes of carbon.
Modeling has demonstrated the feasibility of deploying CO2 transport infrastructure within networks, yielding lower costs per tonne than anticipated. This can be accomplished by planning the network over an extended time horizon to take advantage of existing rail and highway assets more effectively, while eliminating the need for costly new infrastructure investments for storage and transport of CO2. Optimal networks for cost-optimal CO2 transportation have recently been planned for Switzerland including Basel, Rotterdam and Northern Lights storage sites.
Storage
Over the last decade, there has been an explosion of investment and enthusiasm surrounding carbon capture and storage (CCS). CCS technology can reduce greenhouse gas emissions by capturing and storing them before they enter the atmosphere – but at an extremely expensive price tag; other ways such as renewable energy production, electrification and public transit offer far cheaper and more effective emissions reduction solutions than CCS.
Simple put, CO2 capture and transport to an underground geological formation for long term storage is currently practiced by 30 commercial-scale projects worldwide and 11 more at various stages of development; currently there are 30 operational commercial-scale projects, 11 under construction and 153 more that have yet to be developed.
Captured carbon dioxide can also be put to “utilization”, or productive use, such as enhanced oil recovery (EOR). EOR involves injecting it into an oil field to increase extraction; while this approach may bring climate benefits depending on its application and fuels it replaces, they do not offer as significant greenhouse gas reductions as dedicated storage facilities do.