The global climate conversation has put the spotlight on geological storage of CO2, a piece that can help cut emissions, but whose real scope is being recalibrated with new data. Pioneering projects in the North Sea They are pushing technology towards a commercial scale, while science reminds us that the useful subsoil is not infinite and that it will be necessary to carefully select where, how much and for what purpose it is injected.
At the same time, the idea that storage cannot act as a carte blanche to continue burning fuels is gaining ground. CO2 is a greenhouse gas which traps heat and exacerbates global warming; therefore, its capture and containment must fit into strategies that prioritize direct emission reduction and reserve underground capacity for truly climate-friendly uses.
Capacity and limits of geological storage
A recent study led by the IIASA and the Grantham Institute at Imperial College estimates that secure global capacity carbon storage capacity is about a tenth of what was previously announced. Under safety and environmental exclusion criteria, the technically usable volume is significantly reduced.
The reasons for this reduction are to rule out formations at risk of leaks, active seismic faults, protected areas and areas close to large urban centers where aquifers may be compromised. Sites are also limited in deep seas (more than 300 m) due to costs and complexity, and cross-border reservations are avoided due to their political sensitivity.
With that filter, storage is treated as a finite and strategic resourceThe work indicates greater potential in countries with extractive tradition, and highlights relatively safe locations in Saudi Arabia, Congo and Kazakhstan, while regions such as Norway, Canada or the EU their options are reduced compared to previous estimates.
The same analysis estimates that, in the best case scenario, underground injection would contribute to reducing warming by around 0,7 ° C, far from the more generous expectations of years ago. Hence, several scientific voices insist on managing this asset with prudence: what is buried today for offset fossil emissions will not be available tomorrow for hard-to-shoot sectors.
Even in Europe, practical dilemmas arise. Countries with low local capacity, such as Belgium, have signed agreements to store emissions with third parties (e.g., Norway), a solution that could be strained if geological space proves scarce and more contested.
Northern Lights: first injection under the North Sea
While science refines the map of the subsurface, industry sets milestones. Northern Lights Consortium (Equinor, Shell and TotalEnergies) carried out the first injection in a saline reservoir at about 2,6 km deep under the seabed, within a program supported by the Norwegian State to manage European industrial CO2.
The scheme is simple to explain, although complex to execute: capture emissions in chimneys from intensive plants (such as cement, steel or energy), the gas is cooled and compressed until it liquefies, it is transported in tankers to the Øygarden terminal (near Bergen) and from there it is injected through a submarine pipeline of about 110 km towards the porous rock formation, sealed by an impermeable layer.
At that depth, CO2 remains in a state supercritical, a condition that combines the properties of gas and liquid and favors their long-term confinement. Reservoir selection requires geophysical studies to verify the integrity of the rock and the absence of discontinuities that could allow escape.
The first delivery of stored CO2 comes from the plant Heidelberg Materials in Brevik (Norway), and the consortium starts with a capacity of 1,7 million tons per year, with plans to expand towards 5,5 million as the decade progresses. All of this replicates, in a controlled manner, the natural mechanisms that have maintained oil and gas trapped for millions of years.
The operation is considered a decisive step in demonstrating the technical and commercial viability of carbon capture, transport and storage (CCT) in Europe, especially for industries where electrification or process substitution is more difficult or expensive in the short term.
Marine value chains: the Havstjerne case
The logistics chain for CO2 does not end with injection. In the Norwegian Continental Shelf, K Line Energy Shipping (Kles) and Havstjerne ANS (Harbour Energy Norge AS and Stella Maris CCS AS, the latter of Yinson Production) have signed an MoU to mature solutions for transport, storage and injection on the Havstjerne license.
The agreement explores an architecture based on a floating storage injection unit (FSIU) y liquefied CO2 transport vessels, an interesting alternative when there is a lack of land on the coast for terminals or when the distance to the offshore field would make a long pipeline unviable.
Havstjerne is located in the Norwegian sector of the North Sea, about 100 km southwest of Egersund, in an area accessible to ports of Northern EuropeThe license is 60% owned by Harbour Energy (operator) and 40% by Stella Maris CCS AS.
Yinson accumulates experience with FPSO and FSO, in addition to investing in capture technologies since 2021. For its part, the K Line group has a long history of LNG carriers and liquefied gas carriers, and since 2024 Kles has been operating two liquefied CO2 vessels in the first commercial transport and storage service of its kind.
The joint objective is to offer a service safe and cost-efficient to European emitters, aligned with decarbonization plans and a system vision that connects capture, logistics, and underground storage.
Costs, controversies and role in the transition
Although the CTC appears in the reports of the IPCC and IEA As a useful tool for difficult sectors, it remains a technology complex and expensiveIn the European market, it is even easier for many industries acquire emission rights to finance capture facilities and long-term storage contracts.
For now, trade agreements are moving forward cautiously: Northern Lights has signed commitments with Yara (ammonia in the Netherlands), Ørsted (biofuels in Denmark) and Stockholm Exergi (Sweden), signs of traction that, nevertheless, make it clear that the deployment will take time to become widespread without stable regulatory frameworks and financial support.
Critical voices also persist. Professor Mark Jacobson questions carbon capture —and in particular the direct air capture (DAC)— for his energy inefficiency and cost, and raises the opportunity cost: using renewable electricity to capture CO2 could be less effective than using it to replace fossil-based generation.
The reply comes from the side of urgency and sectoral difficulty: there are processes (cement, lime, steel, basic chemicals) for which the CTC can be essential bridge while technologies and supply chains are being redesigned. In addition, 130 DAC plants are in development, and projects such as 1PointFive and Carbon Engineering In Texas they aspire to capture around 500.000 t/year.
The captured CO2 can be used for synthetic fuels for aviation and maritime, to beverages, to lab diamonds or its injection into concrete to improve properties. These are uses with traction, although the climate priority remains to permanently remove and confine carbon where possible.
Geopolitics and governance of a finite resource
The storage map draws new balances. States with great geological potential—such as USA, China, Brazil or Australia— could start with an advantage, while the EU and Norway They appear with narrower margins and depend on more complex transnational agreements.
Researchers such as Joeri Rogelj warn that storage should not justify more pollution, but rather managed as a limited asset in the service of climate security. In other words: underground capacity should be reserved on a climate priority, transparency and risk control.
In addition, the reduction in estimated capacity cools the scenarios of “overshot"who were confident in lowering the temperature later with massive catches. The reading is clear: accelerate the emission reduction and deploy CTC where it provides the greatest net benefit.
Under these conditions, the North Sea projects operate as testing bench for regulation, insurance, CO2 traceability, and cooperation between countries and companies. What is learned there will set the tone for other storage corridors in the coming decades.
Between industrial advances, physical limits, and economic scrutiny, CO2 storage is entering its most realistic phase: technological progress credited with milestones like Northern Lights and alliances like Havstjerne, combined with planning that assumes its finite character and places it as a complement to—not a substitute for—deep emissions reduction.
