Denmark's ambitious plan to capture and store carbon dioxide has hit a stark reality: the country needs underground space equivalent to 5,000 Olympic-sized swimming pools annually to meet its climate goals. A recent government bid for carbon capture and storage (CCS) projects closed with fewer commitments than hoped, highlighting the immense scale and complexity of this emerging technology. Despite this, experts insist that CCS is non-negotiable for decarbonizing industries like cement and waste incineration, setting the stage for a critical decade of development in Danish energy and environmental policy.
The Immense Scale of the Task
The numbers are daunting. To achieve long-term climate targets, Denmark must eventually store between 5 and 6 million tons of CO2 underground every single year. Professor Philip Loldrup Fosbøl from DTU Chemical Engineering provides a vivid analogy: because liquefied CO2 has a similar density to water, that annual volume translates to the contents of 5,000 to 6,000 standard swimming pools. 'Even if we transformed the entire society, there would still be CO2 that cannot be removed,' Fosbøl said. 'It must be rescued with CO2 capture.' The government's more immediate target, outlined in a recent tender, was to secure storage for 2.3 million tons per year. However, initial indications from the closed bid suggest that offers from companies will fall short of this volume, underscoring the gap between ambition and current market readiness.
A Bidding Process with Modest Results
The Danish government's CCS tender, which concluded recently, was a key step in mobilizing private investment. It invited companies to bid for contracts to capture and store CO2 from hard-to-abate sectors. One notable participant was cement giant Aalborg Portland, an industry emblematic of the challenge as cement production inherently releases CO2. While the full results and awarded contracts are yet to be finalized, the preliminary outcome indicates that the total CO2 volume committed by bidding companies is less than the state's target of 2.3 million tons annually. This shortfall does not mean the projects are failing, but it reflects the early-stage nature of CCS technology in Denmark. There are currently no operational large-scale CO2 capture and storage facilities in the country, with the first pilot projects expected to begin operations later this year.
The Technical and Economic Hurdles
Beyond the sheer physical space required, the CCS journey is fraught with technical and financial challenges. Tobias Johan Sørensen, the technical lead for CCS at the think tank Concito, points out the lack of extensive local experience. 'Fortunately, there are several methods,' Sørensen said. 'But it costs money, and it takes a long time to develop. This is something we are only beginning to learn in Denmark now.' The process involves capturing CO2 from point sources like waste-to-energy plants, biogas facilities, and cement factories, then compressing it into a liquid for transport and injection into suitable geological formations beneath land or seabed. Each step—capture, transportation, and secure geological storage—requires significant capital investment and operational expertise. The cost of developing this infrastructure and the long timelines for project approval and construction are major barriers that the tender aimed to overcome through state-backed contracts.
Storage Sites and Geological Logistics
Identifying and preparing adequate storage sites is a monumental task in itself. Denmark is prospecting for suitable porous rock formations, such as depleted oil and gas fields or deep saline aquifers, primarily in the North Sea. The logistics involve not just the injection sites but also a network of pipelines or shipping routes to transport the captured CO2 from industrial plants to these reservoirs. The safety and permanence of storage are paramount, requiring rigorous monitoring to ensure the gas does not leak back into the atmosphere. Professor Fosbøl's swimming pool analogy brings the spatial challenge home: finding and preparing geological space for what amounts to thousands of pools of liquid CO2 annually is a continuous, year-on-year engineering endeavor. The tender's focus is on the first million-ton-scale steps, but the system must be designed to scale up rapidly to handle the multi-million-ton annual flows needed by 2030 and beyond.
Industry's Role and the Path Forward
The participation of companies like Aalborg Portland is crucial. For such industrial emitters, CCS is often the only viable path to deep decarbonization while maintaining production. Sørensen emphasizes that CCS 'does not stand in place of the work with' other climate mitigation efforts like renewable energy expansion, but complements them for sectors where alternatives are scarce. The modest results of the first tender are likely a reflection of the technology's nascency and the perceived risks. Industry observers suggest that clearer long-term policy signals, more experience from pilot projects, and potential cost reductions through innovation and scale will be necessary to attract greater investment in future bidding rounds. The Danish Energy Agency is expected to analyze the bids and announce the awarded contracts, which will provide a clearer picture of the project pipeline and its anticipated contribution to the 2025 and 2030 climate targets.
A Critical Juncture for Danish Climate Policy
Denmark stands at a pivotal moment. The country has legislated a 70% reduction in greenhouse gas emissions by 2030 compared to 1990 levels, and CCS is a cornerstone of that strategy for the industrial sector. The current gap between the storage need and the contracted capacity reveals the steep hill ahead. Success will depend on consecutive rounds of tenders, accelerated technological learning, and perhaps international cooperation on storage infrastructure in the North Sea. The first injection of CO2 into Danish subsoil, expected soon, will be a symbolic milestone, but the real test is building a reliable, cost-effective, and massive system within this decade. As Professor Fosbøl notes, this captured CO2 represents emissions that society cannot otherwise eliminate. The question is no longer just about capturing it, but whether Denmark can build the underground ark fast enough to hold it all.