Carbon Capture and Storage (CCS) is a technology which captures emissions of CO2, then stores them underground in geological formations such as deep saline reservoirs or coal beds. CCS may also include CO2 “utilisation”, where captured CO2 can be utilized to produce products such as fuels, building materials or improved oil recovery.
What is CCS?
CCS captures and stores carbon dioxide produced from power plants and industrial processes, preventing it from being released into the atmosphere and enabling low-carbon energy production as well as mitigating emissions from sectors that cannot easily be decarbonized such as cement, steel and fertilisers.
At present there are 26 commercial scale CCS projects operating worldwide that capture CO2 through flue gases, compress it, and then transport it long distances to storage sites for long-term storage. These include natural gas processing facilities, ethanol refineries and coal-fired power generation stations with the capacity to capture up to 49 MtCO2/year of CO2.
Barriers to wider adoption of CCS include economic and political considerations. Emissions taxes and cap-and-trade systems that monetize carbon can provide incentives for its deployment, as can government research grants and tax credits. Furthermore, CCS requires significant investments and energy input, so operators need compensation for this added expense in order to make it worthwhile.
Why is CCS important?
Carbon capture and storage (CCS) is an integral part of climate change mitigation as outlined in the Paris Agreement. CCS involves collecting CO2 emissions from power plants and industrial processes using fossil fuels, transporting and storing them underground before recovering renewable energy for use if appropriate; its application includes coal production as well as natural gas or oil-sand production as well as renewable power integration; it’s especially helpful in decarbonizing sectors with difficulty transitioning to 100% renewable sources, such as cement production or those located in regions without sufficient renewables available as CCS helps decarbonize sectors which cannot switch completely to 100% renewables such as cement production or steel production for decarbonisation purposes.
However, the introduction of CCS should not be seen as an excuse to increase fossil fuel usage; even with CCS installed fossil fuel usage would still need to be significantly decreased in order to reach net-zero global warming. Therefore CCUS must be supplemented by other options, including rapid investment in renewables and carbon removal from the atmosphere through enhanced natural carbon sinks like tree planting.
How does CCS work?
CCS works by extracting carbon dioxide (CO2) emissions from industrial sources such as smokestacks, then transporting and storing it at an isolated site for extended storage periods. CCS technology may also be applied to biomass to harvest its carbon for energy production in what’s known as Bioenergy with Carbon Capture and Storage (BECCS) processes.
CO2 is separated from other gases using an amine solvent before being compressed into liquid form for transportation through pipelines, often at high pressure, to its storage site. Therefore, CCS projects tend to be located nearby existing power plants or near pipelines for maximum efficiency.
CO2 storage technologies vary, with deep saline aquifers being the most prevalent method. Other options for CO2 storage could include depleted oil fields or abandoned coal mines; however, these methods require significant government support in order to be scaled up effectively.
What is the future of CCS?
As climate leaders gather at COP21 for their United Nations Climate Conference (COP21), questions surrounding carbon capture and storage’s future are once more being raised. Capture technologies are improving and costs are decreasing, yet massive scale implementation of carbon capture requires overcoming several significant hurdles.
One major obstacle for CCS lies in the limited storage sites available. Transportation of CO2 from power plants to these locations – often saline aquifers or depleted oil and gas fields – often takes hours, further complicating CCS efforts in parts of the world without geological formations suitable for storage.
Regulatory delays add another cost element to CCS projects, and cancelled ones, such as Texas Clean Energy Project, Longannet Peterhead White Rose (all UK), Lake Charles Kingsnorth facilities in the US have shaken investor confidence and reduced investment in CCS technology.