What is the Difference Between Carbon Storage and Sequestration?

By Ibtisam AbbasiReviewed by Laura ThomsonFeb 11 2025

The recent shift toward sustainability and tackling climate change has been possible due to efficient carbon management.¹ A major method of reducing the carbon footprint is long-term carbon storage, with carbon sequestration technology playing a key role. While both methods and technologies aim to reduce harmful carbon-based emissions and play a vital role in combating global warming, studying and understanding the difference between both methods is essential.

Image Credit: Miha Creative/Shutterstock.com

What is Carbon Storage Technology?

Carbon capturing and storage is a critical method that can efficiently reduce the carbon-based harmful substances present in the environment. It involves long-term storage of carbon using appropriate resources to ensure a reduction in the carbon footprint. A key step in long-term safe carbon storage is the transport of the captured carbon, while the most crucial step is the choice of long-term permanent storage.²

Carbon Transport and Storage

Generally, experts use carbon storage technology to capture CO₂ from sources that produce extensive amounts of CO₂. After capturing CO₂, it needs to be transported to carbon storage sites, where it does not cause any harm to the ecosystem. Experts have carefully designed transport mechanisms where carbon is initially compressed and transported using pipelines, ships, rails, and trucks.³

Carbon storage uses two main methods: deep geological storage and mineral storage.

Geological Carbon Storage Technology

Geological carbon storage (GCS) is key for carbon storage technology and is crucial in carbon management. Geologic structures are capable of efficiently storing the captured CO₂. Experts have used various critical geological carbon storage technologies, including depleted oil and gas fields, CO₂ storage in saline aquifers, and utilization of deep coal seams for CO₂ storage.⁴

Depleted oil and gas fields are critical for CO₂ storage owing to their extended hydrocarbon retention capability. A small-scale CO₂ storage project in a depleted oil and gas field was completed in Australia for the Otway project. Until 2011, experts measured the amount of CO₂ stored at the geological site to be about 65,000 tons.⁵

Carbon Storage in Saline Formations

Saline formations, also known as aquifers, are sedimentary layers of brine that are not fit for drinking. For CO₂ storage in aquifers, a storage reservoir with appropriate porosity, a sealing cap, and trapping structures are required.

Due to the widespread availability of saline formations, they can be a key carbon storage technology. However, the depth of the carbon reservoirs of aquifers must be at least 800 m. This converts carbon into a supercritical fluid with a much higher density and can be stored in much greater volumes.⁶

Among the key carbon storage mechanisms of saline formations, stratigraphic carbon trapping and storage, solubility, and mineral trapping are key technologies. The first large-scale industrial CO₂ storage using saline formations is the Sleipner project. The project has been active for more than 20 years, with no CO₂ leakages detected, highlighting the efficiency of aquifers for carbon storage.⁷

Other efficient methods for carbon storage include coal seams, in-situ, and ex-situ carbon mineralization. These carbon capture and storage technologies have been useful in reducing CO₂ emissions, leading to much attention from governments and experts worldwide.

Limitations of Carbon Storage

While carbon storage has been essential for combating climate change, the technology has several limitations and risks. Major environmental and health risks include CO₂ leakage, changes in groundwater levels, and seismic activities due to CO₂ reservoirs.⁸ Some researchers fear that injecting CO₂ into geological sites for storage can lead to extreme chemical reactions with underground minerals.

Some industrial analysts are also concerned by the high costs of carbon storage technology. Despite all these challenges, carbon storage has undoubtedly proven to be a core technology for preserving the environment.

What is Carbon Sequestration?

Carbon sequestration is the process of capturing and initially storing carbon until a permanent, long-term “carbon storage” process is designed and implemented to ensure safety. In this way, the carbon sequestration process is also used in tandem with carbon storage technology to achieve net-zero emission goals.

In simple terms, carbon sequestration is the process of carbon capture and temporary confinement of the captured CO₂. The efficient removal of carbon via different sequestration techniques aids in reducing the concentration of greenhouse gases in the atmosphere.⁹

Methods of Carbon Sequestration

Natural/biological carbon sequestration

Biological sequestration techniques play a key role in capturing unwanted carbon-based components. The U.S. Geological Survey experts have identified that forests, peat marshes, and wetlands are key biological agents that capture CO₂ and store it for key processes. Environmental experts refer to the atmospheric carbon captured by oceans and coastal ecosystems as “Blue Carbon”.¹⁰

Tree plantation and restoration of dense forests are emerging impactful techniques when it comes to carbon sequestration. Tropical forests capture a substantial amount of Carbon via photosynthesis and regulate CO₂ concentration. Furthermore, research has highlighted that species-rich biodiverse forests are much more capable and efficient at carbon capturing than single-species forests.¹¹

Carbon Capturing Processes

The main methods for capturing carbon include pre-combustion, post-combustion, and oxy-fuel combustion. In pre-combustion, the fossil fuels are subjected to a carefully designed pyrolysis technique, generating harmless gas fuels like H₂. The harmful carbon in the fuel is converted to CO_2, which is separated using appropriate techniques.

In post-combustion carbon capture, flue gases emitted as a result of combustion of fossil fuels, capture the excess carbon, which is then extracted using absorption, adsorption, or membrane separation technique. In oxy-fuel combustion, fuels are reacted with pure oxygen to produce CO₂ and H₂O as by-products of oxy-fuel combustion. The exit stream of the oxyfuel combustion process contains high quantities of CO_2, which can be separated from the flue gas using any appropriate method.¹²

Popular Artificial Carbon Capture Methods

Researchers have also developed artificially synthesized substances for carbon sequestration. Eco-friendly aggregates capable of carbon capturing using biochar, and domestic wastes have been developed in laboratories. The experimental testing by experts revealed that these artificial aggregates could capture carbon with a maximum carbon intake rate of 26.67 kg/ton.¹³

Direct Air Capture: The Most Popular Carbon Capture Technique

The most popular technique is arguably the Direct Air Capture (DAC) method to remove harmful excessive carbon from industrial sites. These methods directly capture CO₂ from the atmosphere. Statistics have revealed that 27 DAC plants have been commissioned worldwide, and around 130 new DAC facilities are in development to accelerate carbon capture.

Two distinct methods are implemented in DAC plants. Solid DAC involves using solid adsorbents in DAC plants in low operating pressure conditions at 80-120 ℃. The other method is liquid DAC, which focuses on aqueous solutions (such as potassium hydroxide) that capture CO₂ directly from the atmosphere. While DAC is becoming popular, it is a costly technology and is currently operating on a very small scale, with more technological advancements expected in carbon capture technologies.¹⁴

What Differentiates Carbon Storage and Carbon Sequestration?

Experts define carbon sequestration as capturing harmful carbon substances using natural/biological or artificial physiochemical methods to remove excessive carbon greenhouse gases. It also involves capturing anthropogenic CO₂ from stationary sources such as power plants. Experts precisely calculate the total amount of carbon absorbed and captured by planted trees and soil when calculating forests' biological carbon capture potential. Some analysts also categorize the carbon sequestration process as a type of geological engineering that reduces carbon concentrations due to natural phenomena.

On the other hand, carbon storage is mostly aimed at safely transporting and long-term storage of the CO₂ produced at industrial sites using geological reservoirs, deep spaces, and minerals.¹⁵ The sequestration process does not involve any transportation, while for the carbon storage process, the excess carbon initially has to be safely transported to the reservoirs.

Real-World Implications of Carbon Storage and Sequestration

In 2023, the U.S. Geological Survey conducted a comprehensive nationwide assessment of the sequestration and storage potential. Using geological sequestration techniques, it estimated a long-term carbon storage capacity of around 3000 metric gigatons.¹⁶

Various projects have been initiated in different countries to take advantage of carbon sequestration and carbon storage. A renowned carbon capture project, the Ravenna Carbon Sequestration and Storage (CSS) project is now a crucial project for the European Union, aiming to develop 50 million tons of carbon storage by 2030.

Italian multinational energy companies Eni and Snam have started injecting CO₂ initiating phase 1 of the Ravenna CSS. The estimated carbon storage for phase 1 is around 25,000 tons annually, making it a significant milestone in the European net-zero emission project.¹⁷

The Asia-Pacific region is also developing CSS technology rapidly, with countries like Japan, Australia, Malaysia, and Indonesia investing in CO₂ storage technology. Indonesia has launched its first CSS project in West Papua province, which has the capacity to store 1.8 Gigatons of carbon, with an investment of around 2.6 billion dollars.¹⁸

Major investments by governments and multinational companies worldwide prove that carbon sequestration and storage are key technologies in combating climate change. To make these technologies established and viable for all nations, cost-effective carbon storage solutions and preventive measures against carbon leakage must be ensured.

References and Further Reading

1. Safdie, S. (2024). What is Carbon Management? Greenly. [Online] Available at: https://greenly.earth/en-gb/blog/company-guide/what-is-carbon-management [Accessed on November 4, 2024]
2. National Grid (2023). What is carbon capture and storage? [Online]. Available at: https://www.nationalgrid.com/stories/energy-explained/what-is-ccs-how-does-it-work [Accessed on November 4, 2024]
3. International Energy Agency (IEA). (2023). Carbon Capture, Utilization and Storage. [Online]. Available at: https://www.iea.org/energy-system/carbon-capture-utilisation-and-storage [Accessed on November 4, 2024]
4. Zhang, Y. et. al. (2022). An estimate of the amount of geological CO₂ storage over the period of 1996−2020. Environ. Sci. Technol. Lett. 9, 693–698. Available at: https://doi.org/10.1021/acs.estlett.2c00296
5. Cook, P. (Ed.). (2014). Geologically storing carbon: Learning from the Otway Project experience. CSIRO publishing. Available at: https://books.google.com/books?hl=en&lr=&id=AsZSBAAAQBAJ&oi=fnd&pg=PP1&dq=Geologically+storing+carbon:+Learning+from+the+Otway+project+experience&ots=fudaNr8lx9&sig=BJiMj8Y8irvrL0i2hcypBDZOzxo
6. Ringrose, P. et. al. (2021). Storage of carbon dioxide in saline aquifers: Physicochemical processes, key constraints, and scale-up potential. Annu. Rev. Chem. Biomol. Eng. 12, 471–494. Available at: https://doi.org/10.1146/annurev-chembioeng-093020-091447
7. Albertz,  M.  et. al. (2023). Perspectives on geologic carbon storage. Frontiers in Energy Research, 10. 1071735. Available at: https://doi.org/10.3389/fenrg.2022.1071735
8. Parker, G. (2022). Carbon, Capture, and Storage: History, Current State, and Obstacles for the Future. Environmental Law Institute. [Online] Available at: https://www.eli.org/vibrant-environment-blog/carbon-capture-and-storage-history-current-state-and-obstacles-future-part-2#:~:text=There%20are%20also%20environmental%20and,routes%20like%20abandoned%20drilling%20wells. [Accessed on November 5, 2024]
9. United States Geological Survey (USGS). (2024). What is carbon sequestration? [Online]. Available at: https://www.usgs.gov/faqs/what-carbon-sequestration [Accessed on November 5, 2024]
10. Climate Adaptation Science Centers, U.S Geological Survey. (2023). Biological Carbon Sequestration. [Online]. Available at: https://www.usgs.gov/media/images/biological-carbon-sequestration [Accessed on: November 5, 2024].
11. Osuri, A. et. al. (2020). Greater stability of carbon capture in species-rich natural forests compared to species-poor plantations. Environmental Research Letters, 15(3), 034011. Available at: https://www.doi.org/10.1088/1748-9326/ab5f75
12. Nanda, S. et. al. (2016). The progressive routes for carbon capture and sequestration. Energy Science & Engineering, 4(2), 99-122. Available at: https://doi.org/10.1002/ese3.117
13. Liu, J. et. al. (2023). A new approach to CO₂ capture and sequestration: A novel carbon capture artificial aggregates made from biochar and municipal waste incineration bottom ash. Construction and Building Materials, 398, 132472. https://doi.org/10.1016/j.conbuildmat.2023.132472
14. International Energy Association (IEA) (2025). Direct Air Capture. Carbon Capture: Energy Systems. [Online]. Available at: https://www.iea.org/energy-system/carbon-capture-utilisation-and-storage/direct-air-capture [Accessed on: November 5, 2024].
15. Zaman, S. (2014). How can I differentiate between carbon sequestration and carbon storage capacity? Research Gate [Online] Available at: https://www.researchgate.net/post/How-can-I-differentiate-between-carbon-sequestration-and-carbon-storage-capacity-of-a-tree [Accessed on November 5, 2024]
16. United States Geological Survey (USGS). (2024). How much carbon dioxide can the United States store via geologic sequestration? [Online]. Available at: https://www.usgs.gov/faqs/what-carbon-sequestration [Accessed on November 5, 2024]
17. Eni (2024). Eni and Snam launch Ravenna CCS, Italy’s first Carbon Capture and Storage project. [Online]. Available at: https://www.eni.com/en-IT/media/press-release/2024/09/eni-snam-launch-ravenna-css-italy-s-first-carbon-capture-storage-project.html [Accessed on: November 6, 2024]
18. Reuters (2024). Indonesia launches first carbon storage project in West Papua. [Online]. Available at: https://www.reuters.com/business/energy/indonesia-launches-first-carbon-storage-project-west-papua-2023-11-24/ [Accessed on November 6, 2024]

Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.