Four Australian energy companies have executed the country’s biggest greenhouse gas emission reduction project.

The voluntary deal, which involves Origin Energy, Oil Company of Australia, Santos and BP Australia, is aimed at bringing a reduction of around 700,000 tonnes of the greenhouse gas methane over a four-year period.

Petrea Bradford, a renewables and emissions trader at Origin Energy, says there were three steps to the deal, which Sydney-based Origin put together.

Brisbane-based Oil