Heat from London's underground will be used to heat homes

Heat from London's underground will be used to heat homes

Londoners often complain about the sweltering heat on certain subway lines, but very soon that same heat will be used to heat houses during the winter months. In what is believed to be a global milestone, waste heat from the North Line will be harnessed and channeled to homes and businesses in the Islington borough of North London by the end of the year.

The project is part of an initiative to provide cheaper and more ecological heat to homes in the area. Islington is already heating 850 homes using green energy generated at the Bunhill Energy Center through gas cogeneration (CHP). With this expansion, a ventilation duct from the North Line will now be used to channel heat into the network.

The project is one of a growing number of schemes across the UK designed to heat homes using 'waste heat' from disused factories, power plants, rivers and mine shafts.

The search for alternative sources of renewable heat has gained momentum after the government's promise to ban gas boilers from new-build homes starting in 2025.

The next phase of the project, to be completed in the coming months, will extend the network to another 450 households.

The tube project could pave the way for capital-wide district heating schemes to heat homes with cheap, low-carbon heat from underground lines.

The Greater London Authority (GLA) estimates that enough heat is wasted in the British capital to meet 38% of its heating demand.

Tim Rotheray, director of the Association for Decentralized Energy, said that district heating schemes were multiplying across the UK as a low-cost tool to tackle the climate crisis.

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

"The opportunity that has become clear for the decentralized energy community is the idea of ​​capturing waste heat and using it locally."

Looking for other alternative sources

In urban and industrial environments, waste heat is produced wherever there are refrigeration systems, thermal power plants or heavy industry. The key to harnessing the heat is to use it locally.

British Sugar's factory in Wissington, Norfolk, channels the excess heat produced by the cooking syrup into a neighboring 45-acre greenhouse used to grow medicinal cannabis. It also pumps some of its carbon emissions into the greenhouse for plants to convert into oxygen.

An even greater source of heat lies beneath many of Britain's towns and cities - in geothermal energy trapped in water at the bottom of old mines. Stoke-on-Trent is working on a £ 52 million project to harness energy from hot water reservoirs deep underground. This will heat the conventional water before it is pumped through the network to customers.

Stoke City Council estimates that the scheme, which will be operational by winter 2020, could reduce its carbon emissions by about 12,000 tonnes a year.

Another project in Edinburgh

In Edinburgh, Ramboll engineers have developed a plan to create a heat network that uses the accumulated water in a large disused mine as a giant underground thermal battery.

Paul Steen, who has proposed the project, believes that the water from the mine offers "massive potential" to help the city achieve its sustainability goals by connecting it to a renewable heating and cooling distribution system.

The flooded mine system is up to 500 meters underground and is 8 km long by 6 km wide.

During the summer, heat produced by cooling systems and heavy industry could be pumped into the aquifer, where it will slowly raise the temperature of the water.

During the winter, the mine water would be pumped to the surface and "low grade" heat would be extracted in a heat exchanger. The water could be pumped through a heat pump to heat homes and businesses.

Engineers in Glasgow have even found heat potential in the River Clyde.

The city's £ 250 million Queen's Quay Regeneration Project will host a project that uses heat pumps to extract heat from river water before connecting it to a 2.5km-long network that includes 1,400 homes, businesses and Public Buildings. (article in English)

Video: Smart Heating Europe (October 2020).