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As the UK works toward its net zero ambitions, attention is increasingly turning offshore, where geological formations under the sea floor may hold the key to long-term carbon dioxide (CO₂) storage. 

Carbon capture and storage (CCS) encompasses a range of technologies designed to significantly reduce emissions from large industrial sources such as steelworks, cement plants and thermal power stations. CO₂ is captured at source, transported and then injected into suitable rock formations deep beneath the surface, typically at depths of over 800 m. Geologists at BGS are working to better understand the subsurface geology of the Central North Sea and its suitability for storing CO₂ captured from major industrial sources. This work could release one of the UK����ʦ�s largest, yet least-developed, carbon storage resources and underpin the in CCS projects.

Despite accounting for approximately 60 per cent of the UK����ʦ�s total estimated CO₂ storage capacity, the Central North Sea remains under-represented and highlights a major opportunity for the Government����ʦ�s clean energy growth agenda. 

A nation rich in storage potential 

Deploying CCS at scale is a key pillar of the UK Government����ʦ�s . Current ambitions are to store at least 50 million tonnes of CO₂ per year by 2030, rising to as much as 170 million tonnes annually by 2050. 

The UK is exceptionally well positioned for offshore CO₂ storage. Estimates suggest that total theoretical storage capacity exceeds 70 billion tonnes. The North Sea Transition Authority (NSTA), which regulates offshore CO₂ storage, launched its first competitive licensing round in 2022 and followed this with a second round announced in December 2025. 

These licences allow operators to explore and appraise potential storage sites as a precursor to applying for permits that enable CO₂ injection. Due to favourable geology and proximity to onshore emission hubs, most licences to date have been located in the Southern North Sea, with additional clusters in Liverpool Bay, Morecambe Bay and the Northern North Sea. However, the region with most storage potential lies elsewhere.

The drive to map this untapped potential

The enormous, currently untapped potential beneath the Central North Sea lies in extensive sandstone formations in the region. Multiple sequences of stacked Palaeogene sandstone units represent a vast potential CO₂ storage resource, with more than 10 billion tonnes of theoretical capacity (approximately one quarter of the basin����ʦ�s total regional storage capacity). These sandstones were deposited between 40 and 65 million years ago in deep-water marine fan systems. The complex stacked and interdigitated nature of these sandstone bodies raises important geological questions that must be resolved before large-scale storage can proceed.

Key considerations include: 

• the degree of connectivity between sandstone units, which has a bearing on pressure during CO₂ injection
• balance between pressure dissipation and pressure interference between neighbouring storage sites, which affects storage capacity
• the effectiveness of the vital sealing layers above and between the sandstone formations, which might be prone to disruption by various geological phenomena
• legacy oil and gas wells, which could act as pathways for CO₂ to escape if not properly assessed

With relatively few licences currently issued in the Central North Sea, robust pre-competitive geological understanding is essential to realise the region����ʦ�s storage potential. BGS geologists have therefore begun a comprehensive programme to better understand the Palaeogene storage system. This work will also help to address regulatory and operational challenges, particularly those related to pressure effects and interactions between disparate storage projects.

John Williams, senior geoscientist at BGS.

Decades of oil and gas exploration have generated a wealth of subsurface data, including drill core that is curated in BGS����ʦ�s National Geological Repository. Drilling core is expensive, costing as much as £20 to 30 million for a single offshore borehole, so the ability to access pre-drilled material is invaluable, both in terms of avoided drilling costs and time saved. Alongside this archived material, BGS has also developed an integrated subsurface database and interpretations comprising existing 3D seismic and well data, and a stratigraphical framework to ensure accurate regional interpretation.

From the late 1990s to the early 2000s, BGS undertook pioneering work to evaluate the potential to reduce greenhouse gas emissions by storing CO₂ in rocks offshore UK, to help mitigate climate change and develop clean energy. This early work focused on the geological storage opportunities in the Southern North Sea and East Irish Sea regions.

Potential storage sites in these regions, first identified by BGS, are among the first to be licensed and permitted by the NSTA for CO₂ storage. For the UK to reach its ambition of storing 170 million tonnes of CO₂ a year by 2050, it will need to look beyond the current well-appraised geographical areas.

The stacked sandstones of the Central North Sea are relatively under-studied, with huge CO₂ storage potential. Our ambition is to assess and characterise the potential geological storage system in this region to enable future CO₂ storage in the UK, fast-tracking the nation����ʦ�s CCS industry.

Michelle Bentham, chief scientist for decarbonisation and resource management at BGS.

BGS is seeking to establish partnerships to help unlock this nationally significant CO₂ storage resource, which could play a crucial role in the UK����ʦ�s transition to a low-carbon future. Interested parties should contact John Williams via enquiries@bgs.ac.uk