‘Ground-breaking’ renewable energy scheme switches from minewater to air as heat source

A RENEWABLE energy scheme to heat council buildings in South Tyneside will forge ahead, despite having to switch from underground minewater to air as its heat source.

Senior councillors say they are “disappointed” with the discovery of a fatal underground flaw, which means the long-awaited and ground-breaking Hebburn Minewater Scheme has had to be scrapped.

But they say they will still heat their buildings in Hebburn with renewable energy, by installing air source heat pumps instead.

The original plan had been to drill down into the abandoned mineworkings below the town, to tap the heat of the warm water trapped in them.

Two boreholes were drilled to a depth of about 300 metres; one to pump the water to the surface and into the council office heating systems, the other to return it underground to recover more heat.

The plan would effectively have turned the underground mine workings into a giant underground radiator, drawing on the earth’s heat to constantly warm the buildings – and cutting out an estimated 320 tonnes of annual carbon emissions.

Frustratingly, excitement at the scheme’s potential was heightened in February, when it was revealed the minewater was even warmer than anticipated, leading to a forecast of bigger carbon savings.

The first of the boreholes was successfully widened to allow pumping, but disaster struck when the drilling to widen the second borehole revealed “stability issues” at only 170 metres, which mean the scheme could not proceed as planned.

Coun Margaret Meling, lead member for economic growth, skills and climate change, said: “We are naturally very disappointed, but we are still committed to generating modern energy solutions using our historical and natural resources.

“Unfortunately, there are no tests or surveys which would have allowed us to foresee this issue; we had to rely on historic maps, which don’t detail the intricacies of the mine workings. 

“With innovation there is inevitably an element of risk, for which we have mitigated, and we will take the learning from this scheme to continue to develop pioneering renewable energy systems.”

She added: “A revised scheme will use air source heat pumps to feed into the energy centre, which will then provide low carbon heat to residents and council buildings via a pipe network, as planned.”

The council says it is “likely” the revised scheme will save roughly the same annual carbon as the original plan.

Coun Meling added: “We are still keen to use minewater as an energy source as part of this scheme and are exploring the option of extracting and reinjecting using the same borehole. However, this will result in less output from the minewater than was originally intended.

“Any minewater that we can use will complement the output from the air source heat pumps.”

Electricity generated locally using solar panels and a combined heat and power unit will also be used to help power the system.

Planning permission had been granted for an energy centre to house the water pumps and other plant equipment, named after the late Professor Paul Younger, an internationally-renowned scientist who was born in Hebburn.

The scheme, which received over £3.9million from the European Regional Development Fund, had been developed in collaboration with the Coal Authority and Durham University.