In a significant environmental shift, the same North Sea waters where Denmark historically extracted oil are being repurposed to combat climate change. A major carbon capture and storage (CCS) initiative, known as the Greensand project, is nearing completion and will soon begin burying imported European carbon dioxide beneath the seabed.
A New Life for Depleted Oil Fields
Led by the British chemicals giant Ineos, the project is located 170 kilometres off the Danish coast. It will utilise a deep, empty reservoir beneath a small oil platform. Mads Gade, Ineos's head of European operations, described it as a pivotal reversal: "Instead of extracting oil, we can now inject CO2 into the ground."
The first phase, scheduled to start in the coming months, is set to store 400,000 tonnes of CO2 per year. The liquefied gas will primarily come from European biomass power plants. It will be shipped to Denmark's Port of Esbjerg and then transported to the Nini platform for injection.
Why the North Sea is an Ideal "Vault"
The region is considered perfect for this technology due to decades of petroleum industry activity. Ann Helen Hansen, a CCS coordinator at the Norwegian Offshore Directorate (Sodir), explained that over 50 years of oil production have provided an "enormous amount of data" on the geological structures.
The North Sea is filled with depleted oil and gas fields and deep rock basins, offering vast storage potential. Estimates suggest the Norwegian sector alone could theoretically hold around 70 billion tonnes of CO2, while the British side has a capacity of about 78 billion tonnes. In Denmark, the Bifrost project estimates a storage potential of 335 million tonnes.
High Costs and Mixed Reactions
Despite its promise, CCS remains a complex and expensive solution. For industries, the cost of capturing, transporting, and storing emissions is currently higher than buying carbon allowances on the market. Offshore storage, while often more publicly acceptable, adds to the expense.
The EU's Net-Zero Industry Act (NZIA) has set a binding target to achieve an annual storage capacity of at least 50 million tonnes by 2030. The Greensand project aims to scale up to 8 million tonnes per year by 2030.
Other projects are also advancing. Norway's Northern Lights—the world's first commercial CO2 transport and storage service—conducted its first injection in August 2025 and plans to increase capacity. The UK has also awarded multiple storage permits.
However, customer uptake is slow. The Northern Lights consortium has secured only three commercial contracts so far, heavily reliant on state support. Environmental groups like Friends of the Earth Norway caution that CCS should not become an excuse to prolong the fossil fuel era. Truls Gulowsen, the NGO's head, argued that emissions from the North Sea's oil and gas activities still far outweigh what CCS can currently offset.
This pioneering project represents a critical test for CCS technology, balancing its potential as a necessary tool for hard-to-decarbonise industries against significant economic and environmental scrutiny.
