Carbon capture and storage (CCS) is an environmental technology used to mitigate greenhouse gas emissions from power plants and industrial facilities, then stores carbon dioxide underground for long-term use.
CO2 can be captured using post-combustion or oxyfuel processes and transported via pipeline, ship or rail to geological formations suitable for storage – for instance depleted oil and gas reservoirs, saline aquifers and other geologic sites are among the many potential sites suitable for this.
Capture
Carbon capture involves extracting CO2 emissions from industrial sources at their source, transporting it, and then permanently storing it underground within porous rock formations. Many technologies used for carbon capture are already deployed at larger scales – for instance in fertiliser plants and refineries.
Emirates Steel in Abu Dhabi’s “Quest” plant separates CO2 from syngas (a mixture of hydrogen and carbon monoxide) using monoethanolamine – an amine-based chemical used in their HYL Energiron process for producing direct reduced iron (DRI). Meanwhile, Boundary Dam’s project designed to remove CO2 from flue gas streams by reacting it with steam is another way of accomplishing the task.
At present, 41 CCS projects exist globally – although most were not designed with climate purposes in mind and don’t operate efficiently to store maximum CO2. To meet net zero ambitions, these technologies must be deployed much more widely, to capture higher proportions of emissions while working with multiple gases.
Compression
CO2 from power plants and other emissions sources is compressed to make a liquid state before being sent through pipeline or ship to underground geological storage sites for permanent storage.
Storage processes depend on the carbon capture technology employed. Post-combustion capture technology, used most frequently, separates CO2 from coal flue gas while pre-combustion removes it before fossil fuel combustion takes place and calcium looping decarbonizes cement production by extracting CO2 from plant’s clinker.
All CCUS technologies require somewhere to store carbon dioxide. This could mean using geologic formations as permanent storage sites; or it could mean using products like concrete to temporarily store CO2. One successful long-term geologic storage operation is Norway’s Snohvit project which also demonstrated how projects could adapt to geological uncertainties by accommodating alternative storage sites.
Transport
Carbon capture and storage technologies capture CO2, which is directly contributing to climate change from emissions before it reaches the atmosphere. Scaling of these processes must occur rapidly in order to meet net zero targets and limit warming below 1.5 degreeC.
As not all emitting facilities will be located close to geologic storage or utilization sites, CO2 transport networks must cover large regions.
Capture, transport and storage systems are an integral component of carbon management supply chains, but their implementation may present unique challenges.
Current project lead times for carbon capture and storage plants – including construction of transport and storage infrastructure – average seven years. However, this time frame can vary depending on where carbon will end up (either as an industrial product or injection into deep geological formations) as well as where its stored.
Storage
Carbon capture and storage (CCS) involves collecting carbon emissions from large sources like power plants or industrial processes that produce cement or chemicals, transporting and permanently storing them underground. CCS should be seen as part of any comprehensive strategy to mitigate climate change; its implementation could significantly lower costs associated with building low-carbon electricity grids by extending coal or fossil-fuel powered plants’ operational lifetimes.
Current commercial-scale CCS installations globally encompass 26 installations currently in operation that have captured and stored millions of tonnes of CO2 emissions from coal-fired power plants and other sources.
These projects have utilized geologic formations with high salt concentration for storage purposes, such as the Sleipner and Weyburn-Midale CO2 storage sites in Norway and Sweden and Snohvit CCS project respectively. Other initiatives have used depleted oil reservoirs for enhanced oil recovery (EOR), an advanced process which injects CO2 at much lower rates than usual production rates into wells for enhanced oil recovery (EOR).