Waste not want not is the city’s new strategy on a potential treasure trove of untapped energy bubbling up at sewage treatment plants.
With energy-laden gases routinely spilling out of treatment plants, city officials are now looking for a private company willing to come in and turn the otherwise odious fumes into a new source of power.
The Department of Environmental Protection is looking for ideas from contractors willing to launch a waste-to-power project at Wards Island, one of the larger of the 14 treatment plants around the city.
“Our largest user of energy could be our largest supplier of energy,” said Deputy Mayor for Operations Stephen Goldsmith.
Goldsmith said the search to tap gas power at treatment plants is part of a far-reaching citywide effort to generate energy from existing sources and “to create maximum value from the assets we have.”
DEP commissioner Cas Holloway said the agency estimates it could generate up to 30 megawatts of electricty through a cogeneration plant at Wards Island.
But the DEP isn’t limiting itself to dirty water to generate power. Another request for expressions of interest will go out to find firms that would come and set up hydro-electric generators from dams at four of the city’s upstate reservoirs.
Wards Island, the second largest treatment plant, was picked because of its size and because the city is now facing a $60 million tab to build a new heating plant — a project that could be replaced with a privately built generating station.
Then “digestor gas” is a byproduct of the breakdown of sewage. Some of it has been used for heating at the plants in the past, but all the excess gas has to be burned off, which creates greenhouse gases, Holloway said.
City officials are hoping to have several proposals from private firms that can be reviewed by early next year. They are slated to replace the Wards Island heating plant in 2012, which would be the target date for a new cogeneration plant.