The London Underground is preparing to be a net zero carbon railway by 2030. Although more sustainable than fuel-powered cars, there is much to be done across the underground network for this to be achievable. One avenue for decarbonisation for which Arup has supported Transport for London (TfL) is how waste heat produced by underground trains can be captured and repurposed. 

Ventilation systems for the London Underground operate continuously to reject heat from the network, providing a year-round potential source of low-carbon heat. Arup was brought in to determine how best to select sites through which to test the approach and to design commercially and operationally feasible systems for heat extraction.   

Combining desktop and on-site research, we developed a bespoke scoring matrix that assessed sites on several factors such as access, constructability and space availability. Now established, this tool can be used by TfL at future locations to help assess future opportunities for heat recovery as the demand for low-carbon heat continues to increase. 

The six highest scoring ventilation sites were progressed to a stage involving partners local authorities, heat network operators, developers and more to determine feasibility and, then, route to market

TfL is a world leader in many environmental initiatives and we are constantly striving to do more to reduce our carbon footprint and help tackle the climate emergency. Heat from the London Underground has the potential to be a significant low-carbon energy source and we have carried out further research with Arup, as part of our energy and carbon strategy, to identify opportunities for low carbon projects across London Underground. 

Lilli Matson

Chief Safety, Health and Environment Officer, TFL