The certification is given to companies whose greenhouse emissions have been offset by their greenhouse reduction activities, in AGL's case for methane gas flaring at landfill projects at Whittlesea in Victoria and Gosnells in Perth.

AGL estimates these projects have reduced the effect of CO2 equivalent emissions by 90,000 tonnes per year.

Methane gas emissions are up to 21 times more harmful to the environment than carbon dioxide produced from electricity generation.