Carbon Capture and Storage (CCUS) technologies reduce emissions from power plants and industrial facilities by sequestering CO2. Once captured, CO2 can either be stored underground for future use as fuel, building materials or enhanced oil recovery, or captured CO2 can be put to productive use within fuels, building materials or enhanced oil recovery systems.
There are currently 26 commercial-scale CCS projects operating and 21 in FEED stages worldwide. CCS can be applied to both fossil and renewable energy sources.
Capture
Carbon capture uses technology to separate CO2 from other gases produced in factories and fossil fuel-burning power plants, and store it underground permanently.
Post-combustion carbon capture (PCCCS), also known as carbon dioxide removal from natural gas and coal (CCS-Gas), works by injecting chemical solvents like amine into industrial plant flue gases to capture CO2. These solvents bind with and extract the CO2.
Carbon is extracted by isolating it from other gases, compressing and sending to storage locations – often geological formations that have previously been used for oil and gas production. Emirates Steel in UAE’s Al Reyadah plant uses monoethanolamine (MEA) to separate CO2 from blast furnace gases before depositing it 2.5 km underground for long-term storage in saline reservoirs containing saltwater reservoirs containing monosodium phosphate reservoirs; though technical issues like corrosion, biological growth and solvent ‘foaming’ have arisen with regard to this project; now its availability has reached 94% availability!
Compression
Carbon capture and storage (CCS) is an emerging pollution control technology designed to limit carbon dioxide (CO2) emissions from fossil fuel power plants and industrial facilities, and then store them underground permanently. While its concept has existed for some time, supporting its implementation in order to mitigate climate change risks is relatively recent.
Separating CO2 from other gases is an integral step in CCS. Most large-scale projects utilize organic molecules known as amines to react and bind with CO2, and then pump that gas into a “reabsorber” reactor where it will undergo stripping processes and be separated from other gases through a process called absorption.
Purified gas is compressed so it behaves more like liquid and transported to a storage site for further injection, usually via pipeline although ship transport is being explored in some regions around the world. Once at its destination, CO2 injection takes place deep underground into geological formations such as depleted oil and gas reservoirs or saline aquifers.
Transport
Carbon dioxide must be transported from power stations or industrial facilities to be stored safely; this may involve transport to deep geological formations such as an aquifer or depleted oil or gas reservoir.
Capital costs associated with transporting CO2 include designing, building, and operating pipeline networks and compression facilities. CO2 can also be transported on ships using special tanks, cargo holds, and connections for efficient loading/unloading operations – an especially essential feature when shipping long distance to offshore storage sites.
CO2 must first be compressed and liquefied into supercritical form for transport in liquid form; this can be accomplished through various means such as reversible adsorption, evaporation or chemical adsorption. Due to the cost involved with this process, pipelines have become the predominant method of commercial scale CO2 transport, while ports play an essential role in helping fill any gaps during this journey – something Bellona Europa is exploring with Ports2Decarb project.
Storage
CO2 gas collected by capture wells is then pumped down wells into deep geological formations where it can be stored long term – such as used oil and natural gas reservoirs, saline formations or coal beds.
CCS must be widely implemented to limit global warming and make carbon capture and storage viable; although, as yet, its technology hasn’t seen widespread adoption due to cost considerations compared with alternative energy sources. Policy modifications must take place for CCS to become viable.
At power plants, CO2 is extracted from flue gases using various methods depending on the type of fuel being burned, then piped directly to storage sites via either pipelines or ship transport if available in certain regions. CO2 collected this way is compressed into liquid-like state before being permanently trapped underground – CCS projects like those built include Kemper power plant in Mississippi which separates CO2 from gasified lignite coal and Snohvit carbon dioxide storage site in Norway are examples.