Cooling supercomputers: a new role for old mines

Above: The generic heat geobattery concept: recycling excess heat from cooling demand and using legacy mine workings to store and transport the heat to users down gradient

The computing facility currently releases up to 70 GWh of excess heat per year. This is projected to rise to 272 GWh once the UK government’s recently announced next-generation Exascale supercomputer is installed there.

The supercomputer cooling systems would be augmented to transfer the captured heat into the mine water – up to a maximum temperature of 40°C – which would then be transported by natural ground water flow in the mine workings, and made available to warm people’s homes via heat pump technology.

If successful, the £2.6 million study could “provide a global blueprint for converting abandoned flooded coal, shale and mineral mine networks into underground heat storage”, say the project’s instigators.

With a quarter of UK homes located above former mines, potentially seven million households could have their heating needs met this way, the researchers suggest.

The Edinburgh Geobattery project – led by Edinburgh-based geothermal company TownRock Energy – is being spearheaded by industry and academic partners from Scotland, the US and Ireland.

The University of Edinburgh is the lead research partner on the project and is providing £500k of funding as part of its own net zero objectives.

Scottish Enterprise has awarded a £1 million grant to the project through the Joint Programming Platform Smart Energy Systems (JPP SES) and Geothermica – two networks that have co-funded projects developing innovative heat and cooling solutions.

A further US $1 million from the US Department of Energy will fund researchers from the Idaho National Laboratory and Lawrence Berkeley National Laboratory.

University College Dublin, whose researchers are funded by Geothermica and the Geological Survey Ireland, and the University of Strathclyde are also project partners.

Edinburgh Innovations, the University of Edinburgh’s commercialisation service, will help make the research findings an investable proposition and support further funding applications.

Lead academic on the project, Professor Christopher McDermott, from the University of Edinburgh’s School of Geosciences, said: “This project opens up the potential for extracting heat stored in mine water more broadly. Most disused coalmines are flooded with water, making them ideal heat sources for heat pumps.”

For further details about the Edinburgh Geobattery project, visit: Galleries to Calories (G2C) | The University of Edinburgh.

The project design is based around the need to provide a working prototype of up to 9 MW of cooling for the University of Edinburgh’s Advanced Computing Facility. The geobattery concept is that the cooling is provided using mine water in a closed loop heat exchanger at the surface, and an open loop heat exchange in the mine workings. Once this heat is distributed and stored in the subsurface, various heat pump technologies in different surface geographical locations can be employed to recover it.