Bunhill, world-first scheme uses waste heat from London Underground

The revolutionary Bunhill 2 Energy Centre, the first of its kind in the world, provides a blueprint for decarbonising heat in potential future schemes in London and around the world, reducing heating bills and carbon emissions while improving air quality and making cities more self-sufficient in energy.

Ramboll has been instrumental in bringing this highly innovative low-carbon solution to North London. The team first produced a detailed study into the feasibility of using heat from the London Underground to supply district heating, and subsequently further developed the design and oversaw procurement and delivery in two extension stages in 2019 and 2026.

Disused station transformed into state-of-the-art energy centre

The new energy centre uses state-of-the-art technology on the site of a disused Underground station that commuters have not seen for almost 100 years. The remains of the station have been transformed to house a huge underground fan which extracts warm air from the Northern line tunnels below. The warm air is used to heat water that is then pumped to buildings in the neighbourhood through a new 1.5km network of underground pipes.

The energy centre and new pipework adds first a further 550 homes and a primary school to the existing Bunhill Heat and Power district heating network and in a subsequent expansion another 1,050 homes consisting of a new council-owned housing development and a new private development with mixed usage (housing, retail and commercial). The network already provided cheaper, greener heat every day of the year to two local leisure centres and more than 800 homes, but with the new energy centre the system now supplies 2,400 homes.

The centre’s combined heat and power technology means it also generates cheaper, greener electricity that is fed into the London Underground network and an adjacent tower block, powering its communal lighting and lifts. In addition, the two-metre fan, installed in an existing six-storey London Underground mid-tunnel ventilation shaft, can also be reversed to help with cooling the Tube tunnels in the summer months.

Innovation delivers low carbon affordable heat

The Mayor of London, Sadiq Khan, said: “It’s great to see this highly innovative project up and running, recycling waste heat from the Tube to provide a low-carbon, affordable way of heating local homes and businesses. I’ve set London the target of being carbon-neutral by 2030. It’s an ambition that will require innovative projects like Bunhill to help deliver it. If we’re truly going to tackle the climate emergency we will need progressive partnerships between local authorities, City Hall, TfL and others as was demonstrated so perfectly by this project.”

The pioneering extensions to the Bunhill Heat and Power district heating network were a collaboration between Islington Council, Transport for London and the Mayor of London. It was funded by Islington Council, which owns and runs the network, and a grant from the European Union’s CELSIUS project.