Notes from the Underground

Under a new scheme, warm air from a disused London Underground (Northern Line) station will support a heat network supplying about 1,000 homes and businesses by the end of 2019. 

The scheme, a joint project between Islington Council, Transport for London (TfL) and engineering firm Ramboll, "will be a low-carbon energy source," a spokesman said, adding that it was also carrying out further research to identify opportunities for similar projects across the network.

A heat pump will capture "waste heat" from a ventilation shaft on City Road, which now pumps out air at 18C to 28C (64F to 82F), he said.

The project is the second phase of Islington's Bunhill Energy Centre, which already warms about 700 homes, Stephen Moore, communications and content officer at Islington Council, told DW.

Lily Frencham, head of operations at the Association of Decentralised Energy, told DW: "Using surplus heat rather than wasting it is a great way to ensure that we cut carbon emissions whilst helping people stay warm at an affordable cost.”

Power to the people

Enough heat is wasted in London to meet 38% of the city's heating demand, according to the Greater London Authority. With the expansion of district heating networks, this could rise to 63% of demand by 2050.

The search for alternative sources of renewable heat has accelerated after the government's pledge to ban gas-fired boilers from new-build homes from 2025.

The project is one of several similar schemes across the UK to warm homes using waste heat from factories, power plants, rivers and disused mine shafts.

Waste heat

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.

British Sugar's factory in Wissington, Norfolk, pipes excess heat produced from cooking syrup into an 18-hectare (45-acre) greenhouse used to grow medical cannabis. 

Stoke-on-Trent is working on a 52-million-pound (€57-million) project to tap energy from hot water deposits deep underground. Stoke city council estimates the scheme, which will be operational by the winter of 2020, could cut its carbon emissions by 12,000 tons a year.

In Edinburgh, engineers at Ramboll have come up with a plan to create a heat network using the water pooled in a disused mine as a giant underground thermal battery. The flooded mine system lies up to 500 metres (1,640 feet) below ground, and measures 8 km (5 miles) in length by 6 km wide.

Paul Steen, who proposed the project, says the mine water offers "massive potential" to help the city meet its sustainability goals.

Meanwhile, engineers in Glasgow have even found heat potential in the River Clyde. The city's 250-million-pound Queen's Quay regeneration project will include a project that uses heat pumps to extract heat from the river water and pipe it into a 2.5 kilometer long network that includes 1,400 homes, businesses and public buildings. 

It may well provide a warm welcome to the delegates attending the UN climate talks in Glasgow next year.