Feel the heat: Paris Métro to warm flats

A zero-carbon heating initiative in Paris plans to harness hot air generated by underground travel to warm up nearby homes
Paris Metro Underground
Hot air generated by commuters on the Paris Métro could heat nearby homes. Photograph: Dave Penman/Rex Features

Warmth generated by sweaty passengers as they commute on the Paris Métro may be used to heat a block of low-income flats located near the Pompidou Centre in the city centre. This could slash the building's energy bill and carbon footprint by a third, according to the property's owner.

The temperature in nearby Rambuteau Métro station stays at a toasty 14-20C degrees all year round thanks to the heat generated by passengers, trains and other machinery. Paris Habitat-OPH, the owners of the building, plan to use the underground heat to warm up water as it courses through pipes. It will then be pumped to the surface into an underfloor heating system in the block of flats.

"It's a huge source of free, zero-carbon heat so it couldn't make more sense," said Dr Patrick James, a researcher at the University of Southampton's School of Civil Engineering and the Environment. "I guess the only problem will be if there's a train strike in the winter, in which case they'll need a back-up source of heat."

The UK is currently considering similar projects. "By 2016, all new residential buildings will need to be zero carbon, so people are definitely starting to think about innovative ways to heat buildings," he said. Heating accounts for roughly two-thirds of the average UK home's carbon emissions.

Normally, it would be prohibitively expensive to hook up a building's heating system to a subway. "You'd have to dig up roads and it just wouldn't be cost effective," said Dan Phillips, head of sustainability at environmental engineering firm Buro-Happold. It only works here because the flats are connected to the subway by an old stairwell which can house the new pipes bringing the heated water to the surface.

Engineering companies will be invited to bid for the contract by the end of the year and Paris Habitat-OPH hopes to start construction in 2011.

Paris is not the first city to attempt such a feat. Heat generated by Central Station in Stockholm is used to heat an office building. And in Oslo, heat is captured from sewerage and used to heat the city.

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