Sewage Could Be Used For…Clean Energy?

There’s an untapped energy source lurking in the pipes beneath our streets. And people are starting to take notice—and do something about it.

The sewage story

Right now in downtown Toronto, Canada, there is a massive 32-feet-wide and 130-feet-deep hole that exists as one of the many components for a sewage waste heat recovery program. The goal? To harness the heat energy of sewage to power the Toronto Western Hospital. Here’s how it works:

  • Sewage is stored in the hole, then “travels in a closed loop out of that big main, through [a] heat exchanger, and then back into the sewer”. The heat exchanger extracts and concentrates energy from the sewage, and uses it in place of natural gas to power boilers and chillers.
  • The heat exchanger can also work in reverse to remove heat from the building and store it in the sewage.

The result

This method of indoor climate control has already proven effective in other parts of the country, and is estimated to remove “the equivalent of almost 2,000 cars worth of carbon each year” and “reduce Western’s heating and cooling needs by up to 90%”.

Find out more about the project.

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