Carbon capture and storage (CCS) technologies reduce emissions from coal-fired power plants and other industrial facilities, playing an essential role in climate mitigation strategies.
CO2 can be stored safely underground through geologic formations or used to produce products like concrete, chemicals and synthetic fuels. As of today, 26 commercial-scale CCS projects are already operating worldwide with another 153 in development.
What is Carbon Dioxide?
Carbon Dioxide, commonly known as CO2, exists throughout Earth’s atmosphere. It’s produced naturally by volcanoes and wildfires, as well as from respiration and fermentation by plants and some animals, as well as through combustion of fossil fuels.
Carbon dioxide (CO2) is an abundant industrial gas that’s sold in high-pressure cylinders for use in inflating life rafts and life jackets, blasting coal, foaming rubber and plastics and using dry ice to cool food or beverages. Medical applications of CO2 include breathing gas for open heart surgery as well as expanding body cavities for easier visibility during exploratory surgeries.
Chemists use carbon dioxide as a solvent in chemical processing, since it is nontoxic, inert, and cold. Carbon dioxide can be found as a byproduct from various industrial processes, including burning limestone to make lime (calcium oxide) or burning natural gas or wood to generate electricity – though without technology that captures it much of it ends up vented directly into the atmosphere where it contributes to global warming.
Capturing Carbon Dioxide
Carbon Capture and Storage (CCS) is an innovative technology which captures CO2 released from power plant smokestacks, then uses or permanently stores it underground for another use, such as making concrete or chemicals. Fossil fuel emissions totaled 32 gigatonnes in 2010, so CCS technology is vital to achieve net zero climate change.
At present, most carbon dioxide capture technologies rely on liquid that chemically absorbs carbon dioxide before it enters a smokestack. But scientists are creating molecules with specific molecular structures to’single out’ and capture carbon dioxide gases directly.
Once CO2 has been captured, it must be transported through a pipeline and sent directly to geological storage sites – such as depleted oil and gas reservoirs, saline formations or coal beds – through which it will eventually be stored for long-term stewardship by developing regulatory frameworks to govern long-term care of these storage sites.
Utilization of Captured Carbon Dioxide
CCUS involves the capture and storage of CO2 produced by power plants and industrial facilities that use fossil fuels or biomass as their main energy source, transporting it via pipeline or ship for long-term storage locations.
Current operations of CCUS projects worldwide number approximately 40; with many in North America. Most use CO2 injection into active oil reservoirs to enhance oil recovery (EOR).
Pilot projects capturing CO2 from biomass sources exist as well, such as at Arkalon bioethanol plant in Kansas and Humber Saltend facility in UK. However, these use still make up only a very small proportion of total CCUS capacity; only EOR offers net climate benefits when indirect impacts are taken into account.
However, upfront costs associated with CCUS systems remain prohibitively expensive (often exceeding $1 billion per plant) and their deployment lags far behind what’s necessary to achieve the IPCC’s Net Zero Scenario.
Storage of Captured Carbon Dioxide
Carbon capture and storage technologies help reduce emissions by collecting CO2 before it enters the atmosphere from power plants and industrial facilities, and then either storing it underground in geological formations, or using it for enhanced oil recovery or manufacturing chemicals. There are currently 30 operational CCS projects worldwide and another 153 that are in various stages of development.
Captured carbon dioxide can also be stored permanently underground geological formations – this method of CO2 sequestration is known as carbon dioxide storage (CSS). Or it can be integrated into products like concrete and cement where its sequestered for as long as those products remain on store shelves.
Biological CCS occurs naturally in nature, where forest and ocean ecosystems sequester carbon from the atmosphere. Unfortunately, technology required for scaling this process up is considered too costly and impractical.