Carbon Capture and Storage (CCS) is designed to mitigate emissions from power plants that use coal, oil or gas as well as industrial sources by collecting CO2 gas and transporting it underground for permanent storage.
At present, there are currently 77 CCS projects operating globally and capturing around 64 million tonnes of CO2 annually. Additionally, their number keeps on increasing rapidly as do those currently under development.
Capture
Carbon Capture and Storage (CCS) is an established technology that can significantly lower CO2 emissions from fossil-fueled power plants and industrial processes, by collecting emissions and permanently storing them underground in geological formations.
Current carbon capture and storage projects tend to rely on inherent process capture and pre-combustion carbon capture technologies. With inherent process capture, CO2 is chemically separated from industrial gas streams while pre-combustion carbon capture combines fossil fuels with hydrogen and oxygen via gasification or reforming processes in order to produce syngas, which is then separated from high pressure carbon dioxide-rich streams.
CO2 captured from industrial processes is transported to permanent underground storage sites by pipelines; over 50 pipelines across the U.S. currently store over 60 million tons per year1. Captured CO2 can also be injected directly into permeable rock formations like depleted oil and natural gas reservoirs or deep saline aquifers for injection purposes.
Compression
Carbon dioxide gas collected is compressed into liquid form before transporting to storage sites – typically through pipelines but also sometimes ships or rail.
Once at its storage site, CO2 is injected into deep geological formations for long-term storage, such as saline formations, used oil and natural gas reservoirs or unmineable coal seams.
Structural trapping is a method for keeping CO2 stored within a storage formation from migrating horizontally or vertically by creating barriers such as fault lines and rock layers to contain it and seal its storage formation. Basalt formations created when thick flows of volcanic lava cooled and solidified provide exceptional trapping potential due to both their physical characteristics and mineral content.
For optimal transport and storage of CO2, its moisture levels must be reduced below specified levels that could potentially lead to pipeline corrosion or hydrate formation. Here are several compression and dehydration technologies with proven track records in CCUS applications below.
Transport
As part of efforts to lower overall CO2 emissions, various options are being explored; carbon capture and storage (CCS) stands out as a viable strategy. CCS involves collecting climate-warming CO2 at its source before transporting and storing it deep underground geological formations over an extended period.
CO2 can be captured at power plants using post combustion or precombustion technologies, or direct air capture (DAC), in which large fans funnel air through machines that filter for CO2. Unfortunately, this technology is both energy intensive and costly.
CO2 is compressed and deeply chilled before being transported by pipeline or ship to an appropriate storage site – this step is central to reaching net zero carbon. Transport costs make a substantial contribution to additional lifecycle cost estimates of CCS plants for coal and gas sources, though their impact tends to be less sensitive than capital or operating and maintenance expenses.
Storage
CCS involves the capture and storage of climate-warming CO2 at industrial facilities (such as power plants), transporting it safely underground for long-term storage. Different technologies offer different solutions, with each having their own set of advantages and disadvantages.
Capturing carbon dioxide can take place at various sources and locations, including coal and natural gas power plants, cement production sites, and fertiliser factories. Once captured, CO2 can then be transported by pipeline to its storage site – usually an underground geological formation such as an oil or gas reservoir or rock type capable of holding it long term.
CO2 is pumped into storage formations where it is injected at high pressure into the ground at high pressure and trapped within the rock layer, where it cannot reemerge – much like in a sponge. Geological storage regulatory frameworks are currently being created worldwide and multiple projects have now started operating to demonstrate this technology.