Under the North Sea’s cold, churning waters, a former oil field is being reborn as a colossal climate bet. INEOS Energy’s Greensand Future aims to inject liquefied CO2 deep beneath the seabed, turning a fossil fuel asset into a carbon vault. The project centers on the Nini field, a remote site near Denmark, where operations will push CO2 into depleted reservoirs about 1,800 metres down—almost reversing decades of oil extraction.
From a distant horizon to a functioning facility, the plan would become the European Union’s first fully operational offshore CO2 storage site when its operations start next year. Greensand will begin by burying about 363,000 metric tonnes of CO2 per year, then scale to as much as 7.3 million tonnes annually by 2030. Denmark has stressed the potential to store large portions of its own emissions, with Mads Gade, CEO of INEOS Energy Europe, arguing that the region could “store more than several hundred years of our own emissions.” A CO2 terminal is being built at the Port of Esbjerg to handle the liquefied gas, and a purpose-built carrier, nicknamed “Carbon Destroyer 1,” is under construction in the Netherlands.
Details about Greensand are backed by Denmark’s Geological Survey, which notes that the sandstone rock forms a chamber with many tiny cavities and that the upper seal rock can hold the pressure induced by CO2 injection. The project was pitched as a climate solution: removing CO2 from the atmosphere by locking it away underground, a route that some scientists say is essential for hard-to-abate sectors. The EU has proposed storage capacity targets, aiming for at least 227 million metric tonnes per year by 2040 as part of a net-zero plan for 2050. The Intergovernmental Panel on Climate Change (IPCC) has described CCS as a tool, not a panacea, while the International Energy Agency (IEA) reported the world emitted about 34.5 billion tonnes of CO2 last year.
Yet CCS remains controversial. Greenpeace Denmark’s Helene Hagel cautions that CCS should not justify delaying real emission cuts and argues that CCS should be limited to sectors where decarbonization is hardest. INEOS’s defenders, including Gade, say the technology is a practical bridge, enabling Europe to avoid abrupt deindustrialization while it transitions. The Greensand project, therefore, operates within a broader energy and climate policy debate: can a few offshore storage sites and the mass capture of biogas emissions meaningfully offset the emissions produced by industry and energy? The answer, for now, lies in a cautious blend of ambition and scrutiny.
At its core, Greensand repurposes the Nini field—an offshore reservoir near Denmark—into a storage site for liquefied CO2 pumped down about 1,800 metres beneath the seabed. The plan includes a CO2 terminal at Esbjerg to receive and ship the captured gas and a dedicated vessel, Carbon Destroyer 1, under construction to transport the CO2. DENMARK’s Geological Survey highlights that Greensand’s sandstone has ample tiny cavities and a robust top seal, making it a suitable containment zone for injected CO2 and its pressure.
Initially, the project targets 363,000 tonnes per year, rising to 7.3 million tonnes annually by 2030, according to INEOS Energy Europe. The company frames this as a way to curb Europe’s emissions while building an industrial capability that can absorb large volumes of CO2 from European biogas facilities and beyond. Mads Gade stresses that Denmark could store a substantial portion of its own emissions, framing the project as an instrument of transition rather than a removal of industrial activity.
Supporters argue CCS is a pragmatic tool endorsed by climate science to reduce atmospheric CO2, especially in sectors hard to decarbonize. The EU envisions significant storage capacity by 2040 as part of its net-zero roadmap. However, critics caution that CCS is not a panacea: the technology must be energy-intensive, and it captures only a fraction of total emissions. Greenpeace Denmark’s Helene Hagel warns against letting CCS serve as a loophole that delays emission cuts, while acknowledging its potential role for hard-to-abate sectors.
The broader policy context includes IPCC guidance that CCS is one tool among many, and IEA data showing global emissions remain astronomical, underscoring the need for parallel reductions in fossil fuel use. If Greensand proves technically safe and economically viable, it could become a template for offshore storage; if not, it may intensify concerns about leakage, energy use, and the real pace of decarbonization.
