North Sea sandstone could be used to store carbon dioxide, report says

Sandstone beneath the North Sea could be used to store carbon dioxide, a new study has claimed.

The British Geological Survey (BGS) report shows how sandstone beneath the North Sea could assist with the UK’s plans for carbon capture and storage (CCS).

CCS encompasses a range of technologies designed to significantly reduce emissions from large industrial sources such as steelworks, cement plants and thermal power stations.

It works by capturing carbon dioxide at the source, transporting it and then injecting it into suitable rock formations deep beneath the surface, typically at depths of more than 800 metres.

BGS geologists are working to better understand the subsurface geology of the central North Sea and its suitability for storing carbon dioxide captured from major industrial sources.

The work could release one of the UK’s largest carbon storage resources which the BGS said could underpin the Government’s £21.7 billion investment in CCS projects.

John Williams, senior geoscientist at BGS, said: “With relatively few licences currently issued in the central North Sea, robust pre-competitive geological understanding is essential to realise the region’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.”

Despite accounting for approximately 60% of the UK’s total estimated carbon dioxide storage capacity, the central North Sea remains under-represented for long-term storing of carbon dioxide.

Key considerations for the BGS include looking at the degree of connectivity between sandstone units, which has a bearing on pressure during CO2 injection, and balancing between pressure dissipation and pressure interference between neighbouring storage sites, which affects storage capacity.

The BGS would also have to look at the effectiveness of the vital sealing layers above and between the sandstone formations, which might be prone to disruption by various geological phenomena and legacy oil and gas wells, which could act as pathways for CO2 to escape if not properly assessed.

Michelle Bentham, chief scientist for decarbonisation and resource management at BGS, said: “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 (North Sea Transition Authority) 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’s CCS industry.”