Minewater heating and cooling: a 21st century resource for decarbonisation

The drive to decarbonise heating has resulted in investigations of abandoned flooded coal mines across the world as they offer potential for heat recovery, cooling and storage of heat.

On 10 and 11 March 2021  BGS, IEA Geothermal and BEIS organised a conference to share current research and lessons learned from both scientific projects and real life projects concerning minewater energy. IEA Geothermal were very pleased to be involved in assisting with this informative symposium, which quickly developed as an opportunity for the international community interested in minewater geothermal to connect. This free-to-attend conference had 500 registrants from 73 countries. Attendees used the Twitter hashtag #CleanEnergyFromTheCoalfields to join in the discussion, which is still in active use for those wanting to learn more and join  our thriving global community.

The conference

Day one

Brett Hagen (BEIS) launched day one of the conference by covering the policy and practice for low carbon heat networks in the UK.

David Banks (Holymoor Consultancy Ltd/University of Glasgow) discussed the risks, potential capital expenditure (CAPEX) uncertainties and made the call for integration of new (and existing) minewater treatment schemes with housing developments.

Gareth Farr (BGS) discussed recently released temperature maps of the British coalfields.

The session continued with discussion on practical issues including:

• opportunities in Newcastle and Gateshead (Jonathan Steven – Groundwater and Geothermal Services Ltd)
• thermo-mechanical modelling for heat/flow cycling in pillar and stall workings (Fiona Todd, University of Edinburgh)
• an overview of the Coal Authority’s approach to turning mine energy into a strategic asset for Britain (Bohdan Iwanskyj, The Coal Authority)

Day two

Steven Hayes (Hayes Tec Ltd) introduced day two with a talk on heat networks.

Florian Hahn (Fraunhofer IEG) talked about the Dennenbaum coal mine in Germany.

Mike Jenkins (Bridgend Council) gave a presentation on early stage feasibility and public engagement in south Wales.

Florian Hahn (Fraunhofer IEG) returned for part 2 of his excellent presentation covering testing at a demonstration site, including interesting heat injection tests.

Charlotte Adams (The Coal Authority) talked about smart systems for mine-energy schemes.

Alison Monaghan (BGS) concluded the event with a presentation on the UK Geoenergy Observatory in Glasgow.

There is obvious scope to link up geo-observatories across Europe to share lessons learned and to facilitate collaboration.

Q&A session

Hosting the conference via Zoom democratised the online Q&A session and we fielded over 130 questions. Regulation, CAPEX and customer acceptance were frequently mentioned, as was the desire to form a specialist interest group to continue creating opportunities for co-collaboration between policymakers, researchers, regulators and developers across the world.

Attendees were able to vote anonymously via three polls suggesting that minewater heating and cooling is a feasible solution for decarbonising heat (62 per cent), CAPEX is considered the biggest challenge for minewater heating schemes (27 per cent) and demonstration schemes complemented with scientific observatories are the best way to ‘de-risk’ the technology (86 per cent).

Due to the global interest in low-carbon mine-energy schemes, demand for this kind of conference, and a desire to continue talking and connecting with one another, we hope to plan a secondary event in the near future. If you would like to be involved then please email Gareth Farr.

Further reading

• Conference agenda
• Recordings of the presentations  
• UK Geoenergy Observatory in Glasgow
• The Coal Authority
• Heat Store Project
• D2Grids Project

About the authors

• Gareth Farr is a hydrogeologist who leads the BGS mine-energy topic
• Brian Carey is the IEA Geothermal executive secretary and is based in New Zealand
• Brett Hagen is the Heat Networks Specialist (HNDU) at BEIS