What is Carbon Capture and Storage?
An essential technology for carbon neutrality
In the face of the climate emergency, carbon capture and storage (CCS) stands as an essential solution in the fight against climate change. This technology reduces emissions by capturing carbon dioxide directly at its source, whether from a power plant or industrial facility, and then injecting it deep underground for long-term isolation [1]. By preventing this greenhouse gas from reaching the atmosphere, CCS plays a crucial role in our collective efforts toward carbon neutrality.
Today, carbon capture and storage represents only about 0.1% of global emissions, or approximately 50 million tons per year [1]. However, to limit global warming to 1.5°C, this technology will need to capture nearly 1 billion tons by 2030 and several billion by 2050 [1, 2]. As European experts on climate strategy have emphasized: "no CCUS, no net zero." Without large-scale carbon capture and storage, the goal of net-zero emissions by 2050 would simply be unattainable [4].
Where and how is carbon dioxide stored?
The journey of carbon to the Earth's depths
Once captured, carbon dioxide embarks on a remarkable journey to the Earth's interior. The process begins with compressing the gas into a dense fluid, which is then injected into deep rock formations located more than 800 meters below the surface [3]. These underground formations function similarly to natural oil and gas reservoirs, with porous rock capable of containing the carbon and impermeable layers above that trap it in place.
Suitable storage sites include several types of geological formations: deep saline aquifers (porous rock layers saturated with salt water), depleted oil and gas fields, and even unmineable coal seams [1]. In Canada, regulations are strict to ensure storage safety. For example, in Alberta, regulations require that storage not intended for enhanced oil recovery be performed at least 1 kilometer deep [5]. This minimum depth ensures that the carbon remains in a high-density supercritical state, thus maximizing storage capacity.
Natural mechanisms for permanent confinement
What makes geological carbon storage particularly promising is the multiplicity of mechanisms that ensure its long-term confinement. First, an impermeable rock layer above the reservoir creates a structural trap, physically preventing the gas from rising to the surface [5]. Next, the carbon dioxide gradually dissolves in the salt water (brine) present in the formation. Finally, part of the carbon chemically reacts with surrounding minerals to form solid carbonates over time, a process called mineral trapping [2].
As experts point out, "dissolved carbon dioxide can react with the surrounding rock to form solid carbonate minerals, permanently trapping and storing this injected portion" [1]. These combined mechanisms (structural, solubility, and mineral) ensure that most of the gas remains trapped underground permanently, thus addressing legitimate concerns about potential leaks.
Different approaches to carbon storage
Geological storage: the solution of choice
Among the various carbon sequestration methods, geological storage largely dominates current CCS projects worldwide. This predominance is explained by its capacity to accommodate very large volumes of greenhouse gases and to keep them isolated for millennia [2]. Saline aquifers and depleted oil and gas reservoirs constitute preferred targets, as they possess the porous space necessary to contain emissions and the geological seals to confine them.
The global geological storage capacity is truly impressive. Analyses estimate that it is in the order of hundreds to thousands of gigatons, enough to offset a significant portion of anthropogenic emissions [2]. This immense capacity makes geological storage a cornerstone of mitigation strategies, particularly for industries where complete decarbonization remains technically difficult or economically prohibitive.
Mineral carbonation: toward ultimate permanence
While geological storage offers a robust solution, mineral carbonation perhaps represents the safest approach in the long term. This process accelerates a natural reaction that normally occurs over thousands of years: carbon dioxide reacts with certain rocks rich in calcium or magnesium to form stable solid carbonates [2]. The result is remarkable: the carbon is literally transformed into rock, virtually eliminating any risk of leakage.
Mineral carbonation can be performed in two ways: in situ, by injecting the gas into reactive rock formations like basalt where it mineralizes underground, or ex situ, by reacting emissions with crushed minerals or industrial waste on the surface [2]. Although this technology is still in its infancy, with pilot projects like CarbFix in Iceland, research suggests it could potentially store billions of tons annually by mid-century if developed at large scale [2].
Biological storage: complementary but not permanent
Nature has stored carbon for eons in forests, soils, and diverse ecosystems. Through photosynthesis, plants and trees absorb carbon dioxide and store it as organic carbon in their trunks, roots, and in the soil [2]. Protecting and expanding these natural "carbon sinks" (reforestation, soil carbon improvement, wetland preservation) constitutes an essential climate strategy.
However, as the Canada Energy Regulator notes, "these forms do not necessarily store carbon dioxide permanently" [5]. A tree eventually dies and decomposes, releasing its emissions, while carbon dissolved in the ocean could return to the air or affect ocean chemistry. Thus, nature-based solutions are vital but must be maintained indefinitely to keep the carbon sequestered. They are best considered as a complement to engineering approaches that offer the permanent "locked-in" storage necessary to stabilize atmospheric concentrations in the long term [2].
Carbon storage in Canada: exceptional potential
Among the world's most extensive geological resources
Canada benefits from an enviable position in terms of geological storage. With approximately 389 gigatons of available prospective onshore capacity, the country possesses one of the most significant resources in the world [3]. This geological wealth is concentrated primarily in Western Canada: Saskatchewan holds about 70% of this potential with 290 gigatons, followed by Alberta with 79 gigatons and Manitoba with 13.5 gigatons [3].
To put these figures in perspective, Canada's total storage capacity could theoretically contain "hundreds of years" of the country's current annual emissions, which amounted to approximately 708 million tons in 2022 [6].
An ambitious expansion underway
Canada is currently accelerating its carbon storage efforts as part of its climate strategy. Government political support (including investment tax credits for CCS and funding for demonstration projects) has intensified in recent years [3]. In 2022, the federal government published the "Canada's Carbon Management Strategy," highlighting CCS as a key element in achieving national emissions targets.
In terms of concrete projects, numerous new CCS initiatives and regional hubs are under development. In Western Canada alone, 11 new storage facilities were under development in 2025, aimed at sequestering emissions from industries such as oil sands, electricity production, cement, and fertilizers [5]. The province of Alberta has adopted a regional hub approach. In 2022, it selected more than 25 proposed projects for in-depth evaluation, all involving dedicated storage sites or sending carbon to shared storage hubs [5].
This trend is moving toward dedicated geological storage in these new projects. In Quebec, innovative companies like Squatex Ressources & Énergies are also contributing to this collective effort by combining their expertise in carbon-neutral drilling with the search for appropriate underground reservoirs for CO2 burial, demonstrating that the energy transition can rely on integrated approaches combining responsible resource exploitation like hydrogen and carbon storage solutions. With its abundant geology and technical expertise, Canada's vision is to use CCS to decarbonize heavy industries (such as cement, steel, refining, oil sands) and even enable negative emissions in the future, for example by combining bioenergy with CCS.
An essential pillar of decarbonization
Carbon capture and storage represents much more than just another technology in our climate arsenal. CCS constitutes a fundamental pillar for achieving carbon neutrality, particularly for industries where emissions remain difficult to eliminate completely. Canada, with its vast geological resources, positions itself as a potential world leader in underground storage [3].
Pioneer projects like Weyburn-Midale and Quest have demonstrated the technical feasibility of safe long-term storage. Now, the crucial transition consists of moving from enhanced oil recovery projects (whose capacity remains limited) to permanent storage in saline aquifers, which offer considerably greater sequestration potential [3]. This evolution will allow full exploitation of the hundreds of gigatons of capacity the country possesses.
As Canada deploys its ambitious program of regional storage hubs and transport pipelines, carbon capture and storage affirms itself as an essential technology for decarbonizing heavy industries and, ultimately, for achieving our collective climate goals. The road to carbon neutrality will inevitably pass through the depths of our subsoil.
References
[1] Lebling, Katie, et al. "7 Things to Know About Carbon Capture, Utilization and Sequestration." World Resources Institute, 16 May 2025. https://www.wri.org/insights/carbon-capture-technology#:~:text=Today%20CCUS%20captures%20around%200.1,billions%20of%20tons%20by%202050
[2] Riedl, Danielle, et al. "5 Things to Know About Carbon Mineralization." World Resources Institute, 22 June 2023. Web. , https://www.wri.org/insights/carbon-capture-technology, https://www.wri.org/insights/carbon-mineralization-carbon-removal#:~:text=impacts%20of%20climate%20change,hundreds%20or%20thousands%20of%20years
[3] Felder, Melissa, Anastasia Hervas, and Chris Noyahr. "Evaluation of Carbon Capture and Storage Potential in Canada." Clean Prosperity, April 2024. https://cleanprosperity.ca/wp-content/uploads/2024/04/Evaluation_of_carbon_capture_and_storage_potential_in_Canada.pdf
[4] Clean Air Task Force, and CCUS Forum (EU). A Vision for Carbon Capture, Utilisation, and Storage in the EU. CATF, 2022. https://www.catf.us/resource/a-vision-carbon-capture-utilisation-and-storage-eu/
[5] Canada Energy Regulator. Market Snapshot: Where and How Is Carbon Dioxide Stored in Canada? CER, 7 Jan. 2025. https://www.cer-rec.gc.ca/en/data-analysis/energy-markets/market-snapshots/2025/market-snapshot-where-and-how-is-carbon-dioxide-stored-in-canada.html#:~:text=While%20EOR%20continues%20to%20offer,on%20third%20party%20carbon%20storage
[6] Environment and Climate Change Canada. Where Canada's Greenhouse Gas Emissions Come From: 2024 National Greenhouse Gas Inventory. Government of Canada, 3 May 2024. https://www.canada.ca/en/environment-climate-change/news/2024/05/where-canadas-greenhouse-gas-emissions-come-from-2024-national-greenhouse-gas-inventory.html