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Do basins offshore in Wales hold the key to reducing carbon emissions?

20 September 2023


Global carbon dioxide (CO2) emissions are on the rise, and the challenge of safely capturing and storing this greenhouse gas is on many national agendas. In this blog, Dr Roberto Loza of Cardiff University’s Net Zero Innovation Institute and the School of Earth and Environmental Sciences, tells us about his research into novel CO2 storage solutions for Wales.

Figure 1. Visualisation of 1Mt CO2 in the atmosphere.

In the UK alone, it is estimated that every year, 331 million tonnes (Mt) of CO2 are released to the atmosphere. This is a large volume that heavily affects climate change. To put it in perspective, 1Mt of CO2 in the atmosphere has the equivalent volume of a rectangle with the height of The Shard and an area covering almost the entirety of London’s Hyde Park (Figure 1). Permanently storing CO2 in deep geological formations is a necessity to reduce atmospheric CO2 levels and reach the Net Zero target by 2050. This is a similar process to the natural way in which oil and gas has been trapped for millions of years at depths greater than 800m, making it exceptionally safe.

At the moment, the UK government is mainly focused on developing the North Sea for CO2 storage as there is already infrastructure that facilitates the short-term implementation of this process. However, for the South Wales Industrial Cluster, which is the second largest CO2 emitter in the UK, storing CO2 in the North Sea is logistically challenging with high financial and environmental implications. The current plan is to ship the CO2 captured in South Wales to an industrial hub such as Humber (1,150 km away) in England or St Fergus (1,300 km away) in Scotland. From these hubs, the CO2 is planned to be transported by new pipelines to its long-term offshore storage underground in North Sea reservoirs. The financial cost of doing this is £10-£12 per 1 tonne (t) of CO2 for shipping costs, plus £5 to £10 per 1tCO2 for pipeline transportation. The environmental cost relates to combustion of ship fuel that releases an equivalent proportion of the transported CO2 ranging from 2-8% depending on the ship size and distance. These high costs pose a challenge for this technology to be sustainable in South Wales, therefore finding nearer CO2 storage sites is key to reducing costs and making it sustainable in the long term.

Figure 2. Map showing Wales’
offshore basins and CO2 emissions
from industrial sites in South Wales.

I am undertaking research to explore closer CO2 offshore storage sites such as in Cardigan Bay, and the Irish and Celtic Seas (Figure 2). These basins have been overlooked due to their historical lack of oil and gas reserves. But for CO2 storage, deep saline aquifers composed of thick, porous rocks provide a natural reservoir underlain by thick impermeable rocks which create a seal, making an ideal trap for permanent CO2 storage. In general, there are three types of traps: (1) domal structural closures, (2) fault traps and (3) stratigraphic traps (Figure 3). Research on fault and stratigraphic traps has not yet been undertaken in saline aquifers offshore in Wales and my research aims to discover their potential.

These types of reservoir traps have not been fully explored and only vintage data is available. New exploration with joint efforts including academic innovation, industry investment and government initiatives are key to making this a reality. I am collaborating with industry who are willing to support this innovative research project, and conversations to collaborate with the South Wales Industrial Cluster are underway.

Figure 3. Types of CO2 traps in the subsurface.

The UK’s climate agenda needs to focus on this area for further investment, as finding large storage volumes offshore in Wales would revolutionise carbon capture and storage in the UK by increasing its overall storage potential to allow it to reach its ambition to store up to 180Mt of CO2 by 2050. For Wales, this can exponentially increase investment into the country and create an entirely new industry, generating new jobs and attracting skilled professionals. This would bring economic benefits and reactivate Welsh communities that thrived during times of high coal demand. At a government level, conversations with Ireland must be carried out, as it is likely that large CO2 storage reservoirs would expand through political borders (for example in the Central Irish Sea Basin) and therefore joint investments would be possible. This is an exciting time to be part of a solution towards net zero.