The neglected clean heat we flush down the drains

In the midst of winter, the streets of Vancouver will be carpeted with a light layer of snow, punctuated by steaming openings where it has already melted. The access holes to the drains below ground are caused by the heat flowing through the city's sewers, warming up the pavements. «There's enough heat in the sewerage system to literally heat up neighbourhoods,» remarks Derek Pope, manager of neighbourhood energy for the city of Vancouver, Canada. «That's what we've been doing here in False Creek since 2010.»

The residents of False Creek, a recently redeveloped neighbourhood of Vancouver, on the west coast of Canada, get their energy from a rather unusual renewable source – their sewage wastewater. Increasingly, municipalities around the globe are harnessing this underground form of excess heat as they decarbonise their energy networks.

Residents in the 6,210 apartments in the False Creek neighbourhood get their heat from renewable energy sources, with sewage heat being the largest contributor.

Sign up to the Future Earth newsletter  to get essential climate news and hopeful developments in your inbox every Tuesday from Carl Nasman. This email is currently available to non-UK readers. In the UK?  Sign up for newsletters here .

Everything that goes down our drains ends up as sewage water – from what we flush down the toilet, to what comes out of our baths and washing machines.  Down the pipe it flows, eventually ending up in a wastewater treatment plant where it is chemically, biologically and mechanically cleaned and treated, ready to be recirculated back into our homes once again. But the heat that's generated from the dishwasher or a long, hot shower is generally forgotten about once it washes down the plughole,