Assessing, Characterising and Enhancing Geologic Carbon Storage and Geothermal Energy in Wales

Cluster Leader: Dr Andy Mitchell, Aberystwyth University

At present, heavy industries such as steel production and oil refinery are an important component of the Welsh economy. These industries are large carbon dioxide sources, and contribute substantially to the 13% of the UK’s greenhouse gas emissions attributed to Wales. Reducing carbon emissions through the development of low-carbon energy will tackle climate change, provide energy security and create jobs and economic prosperity in alignment with the general ambition on sustainable development set out in the Welsh Governments One Wales: one planet report.

Geo-Carb-Cymru determined the potential for geologic Carbon Capture and Storage (CCS) off the north coast of Wales and the feasibility and capacity for groundsource heating in the largely abandoned South Wales Coalfield.


Geo-Carb-Cymru focused on two key strategies for reducing carbon dioxide emissions in Wales:

  • Geologic Carbon Capture and Storage (CCS), which is the injection of carbon dioxide into underground rocks.
  • Ground-source Heating (GH), which relies on transferring naturally produced heat from under the ground into households.

Research activities:

  • Determining the potential for CCS off the north coast of Wales based on: i. structural seabed analysis; and ii. investigation of the role of microbes in the stability of carbon dioxide below ground. The Cluster’s structural analysis included the development of high-resolution 3D geological maps. A combination of laboratory experiments, DNA-sequencing and computer modelling was applied to characterising microbial diversity and carbon dioxide stability dynamics at potential storage sites in Wales.
  • Field demonstration in Alabama of their subsurface bio cementation process for enhanced CCS with partners at Montana State University.
  • Assessing the feasibility and capacity for GH in the South Wales Coalfield, which lies largely abandoned due to the demise of the coal industry. Sub-surface microbial activity may increase the rate of the heat-generating reactions required for GH. The Cluster sampled sub-surface microbial communities across abandoned mines in the region to provide detailed knowledge on the linkages between native subsurface microbiology and temperature to inform the assessment of potential GH generation. They then extended this research to investigate methods of stimulating subsurface microbial activity to enhance GH generation.

Key findings:

  • The risks of fault reactivation and leakage associated with potential CCS sites in the East Irish Sea basin are very low provided that identified pressure thresholds are not exceeded.
  • The East Irish Sea basin’s capacity for CCS is estimated at 2.5 km3, offering 10% of the UK’s subsurface storage potential.
  • Microbial activities can increase the efficiency of solubility trapping of atmospheric carbon dioxide.
  • Advanced molecular microbiology and nano-chemistry techniques provided critical insights into how organisms control carbon dioxide mineralisation in the subsurface and how this may then be manipulated to enhance long-term carbon storage.
  • There is a dynamic microbial population in the South Wales Coalfield that controls key biogeochemical processes for subsurface heat production.
  • Through collaboration with the British Geological Survey Geo-Carb-Cymru worked with pilot mine-water geothermal schemes under development in South Wales, to provide information on the risks of and control measures for biofouling in heat exchange systems – critical for the long-term success of operations.

Publication highlights :

  • Gamboa, D., Alves, T.M. (2016). Bi-modal deformation styles in confined mass-transport deposits: Examples from a salt minibasin in SE Brazil. Marine Geology 379: 176–193.
  • Rassner, S.M.E., Anesio, A.M., Girdwood, S.E., Hell, K., Gokul, J.K., Whitworth, D.E., Edwards A. (2016). Can the Bacterial Community of a High Arctic Glacier Surface Escape Viral Control? Frontiers in Microbiology 7: 956.
  • Clare, M., Chaytor, J. et al. (2018). A consistent global approach for the morphometric characterization of subaqueous landslides. Geological Society, London, Special Publications 477: SP477-15.

The NRN-LCEE produced the following briefing on the policy implications of Geo-Carb-Cymru’s research:

Opportunities for geologic carbon capture and geothermal energy in Wales

The Geo-Carb-Cymru researchers included:

Aberystwyth University

  • Andy Mitchell                 
  • Arwyn Edwards                          
  • Andrew Evans               
  • Andrew Thomas          
  • Martin Wilding                
  • Sara Rassner                 
  • Andre Soares                 

Cardiff University

  • Snehasis Tripathy        
  • Hywel Thomas                           
  • Shakil Masum                
  • Maram Almolliyeh        

British Geological Survey

  • David Schofield
  • Michelle Bentham        
  • Gareth Farr                    
  • Davide Gamboa          

National Coal Museum Wales                           

  • Richard Bevins                          

University of Leeds

  • Lianne Benning

Please see the ‘NRN-LCEE Final Overview 2013-2019’  for further details of the Cluster’s research.