Groundbreaking project uses Underground to heat homes

Groundbreaking project uses Underground to heat homes

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The sweltering temperatures on the tube’s Northern line will soon begin keeping homes in Islington, North London, warm throughout the colder months, under a scheme to harness the heat from the underground.

By the end of the year the project will pipe heat from the underground into hundreds of homes and businesses that are part of a heating scheme in the borough.

The Islington heat network already keeps about 700 homes warm by channelling heat created in the Bunhill Energy Centre, which generates electricity, into local council housing, schools and a leisure centre. The process works via an underground fan that extracts warm air from the Northern line tunnels beneath the Energy Centre.

That air travels over a series of water filled pipes, heating the liquid inside. The water is then warmed to 80° using heat pumps, before it travels around a series of underground pipes and is transferred to communal heating system loops. However, the project doesn’t just re-purpose heat. Using combined heat and power technology it also generates (greener and cheaper) electricity, that’s fed into a nearby tower block and the London Underground beneath.

As the project has so many benefits; reducing carbon emissions, cooling the Underground network, generating income through electricity sales, TfL has greenlit a feasibility study to see if it could be replicated elsewhere. The study is looking at 56 sites: disused stations and ventilation shafts across its network.

Six key sites have been identified, one of which is York Road, between King’s Cross and Caledonian Road. The project is one of a growing number of schemes across the UK designed to warm homes using “waste heat” from factories, power plants, rivers and disused mine shafts.

The hunt for alternative sources of renewable heat has gained pace after the government’s pledge to ban gas-fired boilers from new-build homes from 2025. The next phase of the project, which is due to be completed in the coming months, will extend the network to a further 450 homes. The tube project could pave the way for district heating schemes across the capital to warm homes with cheap, low carbon heat from underground lines.

The Greater London Authority (GLA) estimates there is enough heat wasted in London to meet 38% of the city’s heating demands.

Tim Rotheray, director of the Association for Decentralised Energy, said district heating schemes were mushrooming across the UK as a low-cost tool in tackling the climate crisis.

“Almost half the energy used in the UK is for heat, and a third of UK emissions are from heating. With the government declaring that we must be carbon-neutral within 30 years we need to find a way to take the carbon out of our heating system,” he said.

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