New railway tunnels could provide locally sourced clean, cheap heating and cooling for nearby homes and businesses, according to a new study.

Researchers have found that, depending on the specific location, tunnels on the previously planned HS2 Phase 2b route could generate between 54-98GWh of heat per year.

The study, published in Proceedings of the Institution of Civil Engineers – Civil Engineering, concludes that “energy tunnels” are both technically and economically viable to offer heating and cooling and help meet our future energy needs.

With the Government’s recent commitment to Northern Powerhouse Rail (NPR), the paper’s authors say now is the ideal time to consider this, so that if the route permits, the process can be built into construction plans from the start.

Project lead Fleur Loveridge, Professor of Geo-Energy Engineering at the University of Leeds, said: “The early project stage we’re currently in is the critical time to seriously consider integrating an energy tunnel system, with new rail lines due to be built in the 2030s.”

With the Government’s recent commitment to Northern Powerhouse Rail (NPR), the paper’s authors say now is the ideal time to consider this, so that if the route permits, the process can be built into construction plans from the start. NPR plans include a new line connecting Liverpool and Manchester, and such a transport link is likely to include new tunnels whilst discussions about station options at Manchester Piccadilly, include one that is underground.

Despite the potential benefits of sourcing thermal energy via tunnels, few commercial schemes exist globally, partly due to high initial costs, long payback periods, technical uncertainties, and the need to minimise construction risk and delays.

A trial energy tunnel was installed in part of the Turin Metro extension in Italy. In the UK, attempts were made to develop projects during Crossrail and in Phase 1 of HS2, but neither proceeded to construction.

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