Writer: Evra Haspolat
The increase in carbon dioxide, one of the greenhouse gases that causes climate change, is a great risk for our world. Therefore, reducing emissions is not enough without producing new technologies. This is where CCS technologies come into play. As the name suggests, these technologies, which stand for Carbon Capture and Storage, are a way of reducing carbon dioxide emissions by capturing, transporting, and storing them. This article will cover the working mechanism of CCS technologies. (British Geological Survey, 2022; Štefanica et al., 2016; National Grid, 2024).
How Do They Work
In the capturing stage, the carbon dioxide is separated from other gases produced in industrial processes such as steel and cement factories, coal and gas power plants, or from the atmosphere. Various capture methods are proven effective and applied based on the emission source (National Grid, 2024; Budinis et al., 2024).
After CO2 is separated, it is compressed for transport in the transporting stage. The compressed CO2 is then dehydrated before it is sent to the transportation system. They are usually transported via pipelines, road transport, or ships (National Grid, 2024; Budinis et al., 2024).
In the storage stage, the carbon dioxide is injected into deep underground rock formations often one kilometer or more deep. This way they are safely and permanently stored. About 300 million tones of carbon dioxide have been injected and stored permanently underground since the world has abundant storage available (National Grid, 2024; Budinis et al., 2024).
Figure 1: A visual overview of each step in the CCS process (Budinis et al., 2024).
What Is In Development With CCS
2024 has seen significant growth in CCS plant development based on the Global CCS Institute’s 2024 Report. Currently, 50 facilities are in operation, meaning CO2 is actively captured, transported, and stored. Three of these 50 are dedicated transportation and/or storage projects. Meanwhile, 44 are under construction, meaning a positive final investment decision (FID) has been made. Seven of these 44 are transportation and/or storage. As of July 2024, the report shows that there are 628 projects in the pipeline, a 60% increase from the previous year.
This report’s regional breakdown shows that the Americas region continues to lead the world in CCS facility deployment, with 27 projects in operation and 18 projects under construction last year in the US, Brazil, and Canada. Meanwhile, the Middle East and Africa region had 3 in operation and 6 in construction, Europe and the UK region had 14, China had 6, Asia Pacific and India had 4 in construction and 1 in operation. The U.S. continues to be the global facility leader with 19 projects in operation, thanks in part to strategic and sustained policy support from its federal government (Global CCS Institute, 2024).
Industrial Applications
Four ways that industrial processes can be made less carbon-intensive through the application of CCS will be discussed. All four options are based on storing CO2 on land or offshore, in brines, or in depleted gas fields.
1) Biomass Power Plants
Biomass power plants have the ability that produce electricity by burning renewable biomass resources. The biomass used in these plants consists of organic materials such as agricultural and food-processing waste, forest product waste, sewage sludge, animal waste, or wood pellets. Using these materials which are wastes that are continually available to generate electricity offers environmental benefits since it preserves landfill space and reduces overall emissions. Although burning wood produces very little sulfur dioxide (SO2) when compared with burning coal, some biomass power plants show relatively high nitrogen oxide (NOx) when compared to other combustion technologies. Both SO2 and NOx have serious effects on both the environment and human health (British Geological Survey, 2022).
2) Post-Combustion Capture
The technique mentioned earlier. It is to capture CO2 produced by burning coal from power plants. Transporting it through pipes and storing it in deep underground rock formations. It is a more common technique than others because it is easy to apply to existing power plants (British Geological Survey, 2022).
3) Pre-Combustion Capture
Integrated Gasification Combined Cycle (IGCC) is a power plant that converts coal into synthetic gas (syngas) before it is burned. Impurities such as CO2 in the syngas can be removed before it is burned. The syngas are used to power a gas turbine generator, whose waste heat is transferred to a steam turbine system for greater efficiency. This technique is especially common in hydrogen and fertilizer production plants (British Geological Survey, 2022).
4) Refinery, Stell, Ammonia, or Cement Plants
Refineries are industrial facilities with high carbon emissions. They are large CO2 emitters because they use so much heat and electrical energy on-site and the refining processes themselves produce CO2. Emission reductions can be achieved with carbon capture technologies. The main difference between refinery CO2 capture and power plant CO2 capture is that CO2 emissions are more distributed in the refinery; they will likely need to be captured at several points.
The production of ammonia, alcohol, and synthetic liquid fuels also produces CO2. Smelters and cement factories emit CO2, primarily from the burning of fossil fuels to produce heat and steam, but some chemical processes also produce CO2.
In the production of ammonia, alcohol, and synthetic liquid fuels, if captured CO2 is not sold or used for another process, it is released directly into the atmosphere which is called venting. In some processes, a richer or even relatively pure stream of CO2 is released into the atmosphere, meaning that capturing the CO2 is more cost-effective. In the case of smelters and cement plants, the technology options for capturing CO2 are essentially the same as they are for power plants that burn fossil fuels (British Geological Survey, 2022).
CCS Technologies’ Effect On Ecosystem
Research into the environmental impacts of carbon capture and storage technologies is particularly examining the potential consequences on ecosystems. CCS systems aim to store carbon dioxide safely in geological structures underground with the post-combustion capture technique. However, the possibility of leakage cannot be ruled out; if stored CO2 leaks from the ground to the surface, effects on soil and aquatic ecosystems can be observed. These effects can lead to changes in factors such as plant growth, photosynthesis, and soil moisture balance. The University of Nottingham is analyzing such potential environmental impacts by setting up a special simulation area to examine how CO₂ leaks affect ecosystems. The University has a specialist field facility designed to simulate such a leak so that ecosystem responses can be assessed under controlled conditions. The facility is called ASGARD (Artificial Soil Gassing and Response Detection). Carbon dioxide can be injected into the soil and measurements are made of parameters such as gas concentrations and fluxes, isotopic signatures, soil moisture, root growth, and photosynthesis (Lomax & Steven, 2006).
Conclusion
In conclusion, Carbon Capture and Storage (CCS) technologies play a crucial role in reducing carbon dioxide emissions and mitigating the impacts of climate change. By capturing, transporting, and storing CO2 generated from various industrial processes, CCS significantly lessens the environmental footprint of sectors such as power generation, cement, steel, and ammonia production. Despite the technology's promising potential, there are ongoing concerns regarding possible CO2 leaks and effects on ecosystems. This has prompted leading universities, including MIT, UC Berkeley, and Columbia, to explore innovative CCS solutions that provide effective and timely remediation.
References
British Geological Survey. (2022, November 16). Understanding carbon capture and storage. British Geological Survey. https://www.bgs.ac.uk/discovering-geology/climate-change/carbon-capture-and-storage/
Budinis, S., Fajardy, M., & Greenfield, C. (2024, April 25). Carbon capture, utilization, and storage. IEA. https://www.iea.org/energy-system/carbon-capture-utilisation-and-storage
Global CCS Institute. (2024). GLOBAL STATUS OF 2024 COLLABORATİNG FOR A NET-ZERO FUTURE. https://www.globalccsinstitute.com/wp-content/uploads/2024/10/2024-GSR_20241015.pdf
Lomax, B., & Steven, M. (2024, November 9). Environmental impacts of carbon capture and storage. University of Nottingham. https://www.nottingham.ac.uk/environment/research/environmental-impacts-of-carbon-capture-and-storage.aspx
National Grid. (2024, March 26). What is carbon capture and storage? | CCS explained | National grid group. Welcome to National Grid Group | National Grid Group. https://www.nationalgrid.com/stories/energy-explained/what-is-ccs-how-does-it-work
Štefanica, J., Smutná, J., Kočí, V., Machač, P., & Pilař, L. (2016, January). Environmental Gains and Impacts of a CCS Technology – Case Study of Post-combustion CO2 Separation by Ammonia Absorption. ScienceDirect. https://www.sciencedirect.com/science/article/pii/S1876610216000242
Center on Global Energy Policy. (2021, November 23). Columbia Launches Carbontech Initiative to Bring Climate Solutions to Market. https://www.energypolicy.columbia.edu/columbia-launches-carbontech-initiative-bring-climate-solutions-market/
Chandler, D. L. (2021, January 25). Boosting the efficiency of carbon capture and conversion systems. MIT News | Massachusetts Institute of Technology. https://news.mit.edu/2021/carbon-capture-efficiency-0125
Sanders, R. (2024, October 29). Capturing carbon from the air just got easier. Berkeley News. https://news.berkeley.edu/2024/10/23/capturing-carbon-from-the-air-just-got-easier/
Stauffer, N. W. (2020, July 9). A new approach to carbon capture. MIT News | Massachusetts Institute of Technology. https://news.mit.edu/2020/new-approach-to-carbon-capture-0709
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