World-first scheme is launched using waste heat from London Underground

6 March 2020

Waste heat from the London Underground network is now capable of providing heating and hot water to more than 1,350 homes, a school and two leisure centres in Islington thanks to the pioneering Bunhill 2 Energy Centre that opened yesterday.

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 the people of Islington. Producing first a detailed study into the feasibility of using heat from the London Underground to supply district heating, and subsequently further design development and overseeing procurement and delivery. Find out more about the innovative engineering solutions that formed this world-first energy-centre here.

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, once known as City Road, 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 a further 550 homes and a primary school to the existing Bunhill Heat and Power district heating network, launched in Islington in 2012. The network already provided cheaper, greener heat every day of the year to two local leisure centres and more than 800 homes, but the new energy centre gives the system the potential to supply up to 2,200 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.

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.”

Cllr Rowena Champion, Islington Council’s Executive Member for Environment and Transport, said: “This pioneering project recycles heat that was simply being lost to the environment. We are cutting carbon emissions in a way that also reduces people’s energy bills, helping us to help them at a time when the cost of living is soaring.

“Not only is this contributing to Islington’s commitment to be a net zero carbon borough by 2030, but this initiative also helps to reduce fuel poverty and make Islington a fairer place, while offering our communities a sustainable, cheaper and greener future. I’m very proud of this exciting project, which promises to make a real difference to residents and the environment.”


Lucy Padfield, District Heating Director at Ramboll and Chair of the Association for Decentralised Energy (ADE), comments: “We believe that the use of large-scale heat connected to urban district heating systems will play a major part in decarbonising the UK’s heating energy demand. The use of heat pumps utilising industrial waste heat sources is more carbon efficient than gas-fired CHP, the usual source of heat for district energy schemes. I am convinced that with the increasing use of renewable power sources, large-scale heat pumps connected to district heating systems will play a major role in the future heating of cities in the UK.”

How Bunhill 2 Energy Centre works

During the winter months, a fan in the ventilation shaft extracts warm air from the Tube which travels over a series of water-filled pipes, heating the water inside by a few degrees. The water temperature is then increased to about 80c using heat pumps, which is suitable for domestic and commercial central heating systems. The fan also has the potential to operate in reverse to supply cooler air to the Tube tunnels during the summer months.

The hot water is pumped around a network of insulated underground pipes, and the heat is again transferred to communal heating system loops on housing estates using heat exchangers.

The heating bills for council tenants connected to the network will be cut by 10 per cent compared to other communal heating systems, which themselves cost around half as much as standalone systems heating individual homes. The nearby Moreland Primary School is the first school to be connected to the network, which already serves the pool and facilities at Ironmonger Row Baths and Finsbury Leisure Centre.

The district heating network is greener too because it reuses heat that would otherwise be wasted; those who are connected will be helping to reduce CO2 emissions by around 500 tonnes each year. 

The pioneering extension to the Bunhill Heat and Power district heating network is 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.

Crispin Matson, District Energy Director at Ramboll said: “We are proud and delighted to be here celebrating with our project partners and collaborators whose expertise delivered this world-first energy centre.

With 300,000 new homes needed every year to meet our housing demand the opportunities to establish district energy networks is vast. Ramboll’s ground-breaking solutions implemented at Bunhill and our ongoing investigations show that by using waste heat as a core part of our energy mix, we can deliver cheaper and decarbonised energy to thousands of people in existing buildings and new build developments simultaneously from the same district heating network. We see Bunhill as being very much a project which is looking to the future for district heating.”

Related projects

Heat from the London metro is used for additional heating of 500 households

Bunhill 2 District Heating Network - Heating up London

Ramboll was commissioned by Islington Council in London to design and deliver a district-wide heating network to provide cheaper and greener heat to 1,350 homes plus community buildings in north London, using unwanted heat from the London Underground. 

CGI projection of completed projects, with Wembley Way approach in foreground

Wembley Park regeneration

When property developer Quintain embarked on transforming the long-neglected area surrounding the iconic Wembley stadium, into a new district and exciting hub, they sought Ramboll as an engineering partner who could fully realise their ambitious sustainability agenda.

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