The revolutionary Bunhill 2 Energy Centre is a blueprint for decarbonising heat in London and around the world. It reduces heating bills and carbon emissions, while improving cities' air quality and energy independence.

Using state-of-the-art technology, the first-of-its-kind £10m scheme has transformed remains of a century-old, disused Underground station (Old City Road) into a pioneering energy centre. It now pumps waste heat from nearby London Underground tunnels into local homes, leisure centres and a school.

Through recycling heating that would have otherwise been lost to the environment, the centre reduces fuel poverty and gives its community a sustainable, cheaper and greener future. It also supports Mayor of London Sadiq Khan’s goal of making the city carbon neutral by 2030.

Significant carbon reductions at a bargain

Retrofitting the unused tube was no small feat. It involved capturing excess heat from the Northern line tunnels below, then sending that heat to the water pumped into neighbourhood through 1.5km of new underground pipes.

The solutions behind this needed to be effective but also affordable. In response, our experts at Gleeds performed a capital cost review and developed a whole-life cost model for Islington Council, which owns and runs the Bunhill Heat and Power district heating network.

Not only have 550 homes been added to the existing heating network, but the scheme has also opened the door to supplying up to 2,200 more homes in the future.


  • 10% in gas and electric utility cost savings for social tenants
  • 500 tonne reduction in carbon emissions annually
  • Heating and hot water for over 1,350 local homes, two leisure centres, and a school
Gleeds has demonstrated a thorough and detailed understanding of our energy requirements. Their professional approach and genuine interest in finding cost-effective and workable solutions has been a major factor in securing a greener future for our community. Rodrigo Matabuena, Energy Capital Projects Manager at Islington Council

How it works

In the winter, a fan in the ventilation shaft extracts warm air from the Tube, which travels over a series of water-filled pipes and heats the water inside by a few degrees. The water temperature is then increased to about 80c using heat pumps (the fan can operate in reverse to supply cooler air to the Tube tunnels during summer).

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.

A real difference to residence and the environment

Innovative projects and progressive partnerships are needed today to tackle the climate emergency, and our collaboration with Islington Council, Transport for London, and the Mayor of London embodies just that.

The centre has not only helped the environment but cut energy bills for people at a time when the cost of living is soaring. With this groundbreaking technology comes the potential to replicate similar solutions in other London and UK boroughs, and in other cities around the world with underground transit networks.