AGL has built a landfill gas extraction and generation site at Gosnells.
The energy plant was commissioned late last year and is expected to initially generate about 15.7 million kilowatts of renewable electricity a year, enough to power 3,000 homes.
The facility will offset about 16,000 tonnes of carbon dioxide emissions a year.
In addition, a further 70,000 tonnes of CO2 emissions will be abated because of the combustion of the landfill gas used to generate electricity.