The heat beneath our feet
Beneath our post-industrial towns and cities lies a huge network of disused mines, a legacy of the drive for coal to power Britain’s industrial revolution. Now researchers at the University of Leeds are looking at ways to use this neglected resource to help our move to a low carbon economy.
Flooded mine workings can store excess heat and be used as a geothermal heat source. Mine shafts can house gravity-operated energy storage systems, where excess power is used to raise a suspended weight then returned to the grid when needed by releasing the weight and recovering the energy through regenerative breaking.
Despite these technologies being well established, there are few such schemes in the UK to date, as Dr James Van Alstine, Associate Professor of Environmental Policy, explains:
“The geological and engineering expertise to create these kind of energy projects already exists. What has been lacking are the policy and governance frameworks to finance such schemes, and integrate them successfully into national and local energy networks.”
This is where the Leeds team comes in. By bringing together geologists, engineers and social scientists, they combine the expertise needed to look at both the technical and the policy challenges.
Initial research by the Leeds team in the Yorkshire and Humber region shows the value of this ‘whole system’ approach. Using Coal Authority data, the team mapped the mine workings below the region, and overlaid this with data on energy demand from homes and buildings. They talked to key stakeholders in local government and the energy industry to understand the barriers to implementation. And they looked at two existing schemes –the Seaham Garden Village mine water heating scheme and the Leeds district heating system – to identify the mechanisms that had enabled these to get off the ground.
Professor in Structural Geology and Tectonics, Sandra Piazolo, says: “A number of UK cities have, like Leeds, a district heating system, but these usually take heat from waste incineration plants. Very few local authorities are considering bringing in heat recovered from the disused mine workings beneath their streets. We want to put geothermal on the agenda as an option and enable policy makers to see that there is an opportunity here to be pursued.”
The team have created a policy brief for local authorities, using Leeds as an example of how such schemes could be taken forward. They recommend that, to make the most of the opportunities available, local authorities should share expertise and engage early with key stakeholders and the public. They also recommend that local authorities assess their subsurface assets as early as possible, before plans for above surface developments are finalised. And finally, they also highlight that local authorities should consider ways to create a supportive environment, particularly in relation to local planning policies, that could enable subsurface heating services to go ahead.
Leeds and York City Councils have both already expressed an interest in the proposals. The next step is to get further funding for a pilot project in the region. This would involve geological site assessments to determine the state of the mine infrastructure and further work with both industry and local government to set up the commercial and policy framework for integration into the local energy system.
Download the policy briefing document here.