Councillors were on site at the Green Island facility this week to switch on a purpose-built generator which uses gas collected at the nearby landfill and methane from the wastewater treatment plant.
The generator is capable of producing up to 625kW of electricity, but presently supplies about 380kW. Come spring, it is expected to reach full capacity when additional gas lines become available.
Cr Andrew Noone said the council would "get its money back" through the project within four years.
"There are not many council investment projects that involve a payback period of just four years," he said.
In 2009 the council began collecting and burning gas from the Green Island landfill.
Now it is being transported to the generator via a pipe, and mixed with methane from the wastewater treatment digesters to produce electricity.
It will offset the treatment plant's power consumption and enable easy export of any excess power to the national grid.
Cr Noone said the council had previously tried, but failed, to use waste gas from the Green Island landfill.
"This is a milestone," he said.
Legislative change required the council to capture landfill gas, Cr Noone said.
"The public also wants to see us trying to convert something deemed a waste material into an energy source," Cr Noone said.
"It fits with the sustainability point of view." Wastewater treatment manager Chris Henderson said the generator's life span was "indefinite" provided the machine was regularly maintained.
