Subway stations are hot, so the city of Paris is planning to harness that heat as a way of producing power for a new housing development. The public housing project is already located above a metro station, but will be renovated in such a way as to make use of the human generated heat below it, as opposed to a traditional boiler room.

When you combine the 100 watts of energy produced by each passenger with the heat produced by the moving underground trains, it means that the station's temperature remains between 14-20 degrees Celsius all year. The project will take this warmth and transfer it to heat exchangers, which then move it to heating pipes that are used to heat the 17 homes in the area.

Unfortunately, while it's a great way to reduce carbon dioxide emissions, the process isn't exactly practical and won't be implemented widely across Paris, due mainly to the costs involved. This particular project just happened to be in the perfect spot. "We were lucky to find a passageway that allows us to collect the heat directly from the metro, without having to pay to build one, otherwise it would have been impossible," Francois Wachnick from Paris Habitat told�Reuters.

Work on the housing project is due to begin early next year.