The secure and permanent storage of carbon dioxide (CO2) within a single geological storage formation can be optimised by injecting CO2 at more than one point simultaneously, according to results from a study of rocks beneath the UK North Sea.

The findings could help to unlock an immense CO2 storage resource underlying all sectors of the North Sea for the storage of Europe’s carbon emissions.

The process of storing CO2 captured from power plants and industrial facilities in deep geological formations is known as Carbon Capture and Storage (CCS).

Dr Maxine Akhurst, British Geological Survey, who led the project, said: ‘Our study is one of the keys that will unlock the potential CO2 storage capacity underlying the North Sea and release this immense storage resource.

‘Our results show that by using more than one injection site in a single sandstone operators can store greater volumes of CO2 compared to using a single injection site, so increasing Europe’s capacity to reduce greenhouse gas emissions.’

The research by scientists and prospective site operators  used a UK North Sea case study – the Captain Sandstone – to predict the performance of a potential CO2 storage formation when the greenhouse gas is injected at two points at the same time over three decades.

The study’s conclusions will help to increase confidence among regulators and investors in the secure containment of CO2 within ‘multiple user’ storage formations.

The work has informed how the UK can plan and manage subsurface geological CO2 storage, and design CO2 injection at more than one location by looking at regional-scale performance of an entire geological formation.

It is an important step in the gradual process of developing the UK’s vast CO2 storage potential, which has been estimated at 78 billion tonnes.

The findings also suggest that the Captain Sandstone, which lies more than a mile beneath the Moray Firth off north east Scotland, could securely store at least 360 Million tonnes (Mt) of CO2 in just one sixth of its area when CO2 is injected at a rate of between 6 and 12 Mt per year over three decades.

As a comparison, 360Mt is the amount of CO2 emitted by Scotland’s energy supply sector over 23 years.

Related articles

Researchers on the CO2MultiStore joint industry project used cutting-edge methods, which will, in future, reduce the effort and resources needed to characterise other extensive storage sandstones that could be suitable for CO2 storage.

Energy Minister Fergus Ewing said: ‘Carbon Capture and Storage (CCS) has the potential to be one of the most cost-effective technologies for decarbonisation of our power and industrial sectors, as well as those of economies worldwide.

‘With £2.5 million of funding already committed this year to undertake substantial industrial research and feasibility studies in Grangemouth, the Scottish Government is already playing a pivotal role in the development and commercialisation of this innovative, exciting technology.

‘This research confirms how the huge CO2 storage resource potential beneath the North Sea can be optimised, which, combined with the infrastructure already in place, again reinforces the huge opportunity for Scotland around CCS.

‘CCS can contribute significantly to the diversity and security of electricity supply, and also has a unique role to play in providing a continuing supply of flexible clean fossil fuel capacity that is able to respond to demand in the way that other low-carbon technologies cannot.’

Dr Ward Goldthorpe, programme manager, The Crown Estate, said: “As an active manager of the UK seabed, we’re committed to unlocking value from this natural asset, including working with industry to identify how carbon storage can help the UK decarbonise over the long term.

‘The CO2MultiStore project has provided invaluable insights that will help ensure regional management of offshore CO2 storage formations is used to optimise the potential of this sector and the transition to a low-carbon economy.’