Woodside Energy has rejected the accusation that it is preparing to detonate a "new climate bomb" that would dwarf national efforts to reduce greenhouse gas emissions.
The proposed $50 billion project is designed to bolster the existing Pluto LNG and North West Shelf projects by creating a regional production hub on the Burrup Peninsula in the Pilbara region of Western Australia.
Most of the gas produced by the hub would be exported rather than being used by Australian households or industries.
A report released by the Australian Conservation Foundation (ACF) on Thursday found lifetime pollution from Burrup Hub would cancel out the entire savings from all existing household rooftop solar systems in Australia for more than 344 years.
"Woodside's proposed Burrup Hub gas mega project is a climate disaster in the making," campaigner Elizabeth Sullivan said.
"Plans to start sending gas from the vast new Scarborough and Browse gas reserves to an expanded Burrup Hub would detonate a new climate bomb."
Woodside said the report contained "flawed methodology and creates a misleading picture" of the net impact of several proposed projects.
"Nor does it contain any acknowledgement of the positive role that gas can play in decarbonising the Australian and international economies," a Woodside spokesperson told AAP.
Japanese energy companies recently purchased a quarter of the future Scarborough gas to lock in decades of LNG.
Used to generate electricity, the Scarborough gas field off the Pilbara coast could power the homes of 10 cities the size of Perth for 30 years, for half the carbon footprint of electricity from coal-fired power plants, according to Woodside.
Woodside said the federal government's modelling of the emissions safeguard mechanism assumes the development of the Scarborough field, a second train at Pluto LNG and Browse backfill to replace depleted parts of the North West Shelf.
ACF said the precinct was already Australia's largest polluter and the hub would be in the top 10 biggest carbon bombs globally.
At more than six billion tonnes across its lifetime, emissions from the mega-project would be greater than the annual emissions of the United States or more than 13 times Australia's annual emissions.
The report by Piers Verstegen shows the largest new fossil fuel project in the southern hemisphere would also dwarf Woodside's promised abatement efforts.
The hub would place Australia in the company of countries that are undermining global action on climate change, according to the environmental organisation.
The only countries hosting more polluting oil and gas facilities than the Burrup Hub are Russia, Qatar and Saudi Arabia, the ACF said.
The federal government will soon decide whether to approve aspects of the Scarborough and Browse gas projects and a 50-year extension to the North West Shelf.
"To allow these projects to proceed would recklessly undermine international efforts on climate change and seriously damage Australia's credibility on these issues," Ms Sullivan said.
