Carbon capture and storage (CCS) technology aims to limit carbon dioxide (CO2) emissions from fossil fuels and industrial processes, helping us meet climate change goals of limiting global temperature rises.
CO2 captured from power plants and other sources is compressed into dense liquid form called supercritical CO2, then transported deep underground for geologic storage sites such as old oil reservoirs.
What is CCS?
Carbon capture and storage (CCUS or CCSM) is one of the technologies needed to address climate change. It involves collecting CO2 from industrial sources like power plants, steel mills, cement production facilities and ships and then permanently storing it underground.
Starting off the process involves isolating CO2 from exhaust gases produced when fossil fuels are burned for energy or from industrial processes like ammonia and ethanol production plants, either using post-combustion capture, pre-combustion capture or direct air capture methods.
CO2 that has been separated is then transported to its permanent storage site – typically underground reservoirs filled with salt water or depleted oil and gas reserves, such as Endurance Coal Mine near Grimsby in the UK; or more globally to depleted oil fields in the Gulf of Mexico or saline aquifers beneath the North Sea.
Why is CCS important?
CCS can be an effective weapon against climate change, particularly for emissions from hard-to-abate industries such as steel and cement manufacturing. Furthermore, it complements renewable energy sources by producing carbon neutral electricity when neither wind nor sun are available for power. Unfortunately, most existing CCS projects are used for enhanced oil recovery (EOR) or direct air capture of fossil fuels; EOR involves injecting carbon dioxide under pressure into oil fields to stimulate more production; any associated emissions nullify any purported climate benefits from stored CO2.
CCS does come with its own set of negative impacts. Operating it consumes substantial energy, contributing to additional emissions from power plants. Furthermore, ammonia-based carbon capture process uses harmful substance such as ammonia to capture CO2. Once captured, carbon is transported and injected into geologic formations for permanent storage; unfortunately these processes often happen within communities with high pollution and environmental injustice issues that further compound their problems.
How is CCS done?
CCS uses carbon capture and storage (CCS) technology to capture CO2 produced when fossil fuels are burned for electricity production, heat generation or hydrogen production and permanently store it underground. The three-step process begins by compressing it into manageable form for transportation before injecting it deep underground in geological formations for safekeeping.
Transport of CO2 between power plants or industrial facilities by ship or pipeline then chilled before being loaded onto special transport vessels for delivery to its final storage site is energy intensive; hence it adds emissions overall.
Carbon Capture and Storage (CCUS), has been used since 1972 in the oil industry to enhance oil recovery. Through numerous demonstration projects around the world, CCUS has demonstrated its efficacy at safely and commercially capturing and storing CO2. Typically stored in depleted oil/gas reservoirs or deep aquifers more than 1000 feet (335 metres below surface level.
What is the future of CCS?
Carbon capture and storage (CCS) technology has the ability to significantly decrease carbon dioxide emissions that contribute to global warming when burning fossil fuels or operating certain industrial processes, but its widespread adoption requires policy support such as subsidies for CCS technologies, carbon taxes or limits on emissions from certain industries. Furthermore, its deployment requires significant infrastructure investment from countries that lack geological storage capacity.
Current applications of CCS include power plants that burn coal and industry processes like cement or steel production. Future potential uses may include bioenergy with CCS, where biomass like wood and grass absorbs CO2 during photosynthesis before being burned for energy. Captured CO2 could also be stored underground geological formations like depleted oil reservoirs or deep saline aquifers or used to assist enhanced oil recovery by pumping into old oil wells to flush out harder-to-extract oils.