The A$16.5 billion LNG development will see gas from the Scarborough field processed at Woodside's expanded Pluto LNG facility on the Burrup Peninsula with first gas expected in 2026.
The project has faced a sustained campaign from environmental groups and activists, with the Conservation Council of Western Australia and The Australia Institute releasing a report earlier this year finding that the project would release some 1.69 billion tonnes of CO2 over its 30-year life across all scopes.
Last week, activists were seemingly vindicated when Woodside CEO Meg O'Neill confirmed their analysis when she was asked on ABC Radio what the project's scope 3 emissions would be.
"Look, I believe it's in the order of 1.6 billion tonnes of CO2, but again what's important to recognise is how those emissions would compare with other sources," she said.
However, Energy News understands that the figure is wrong and was mentioned inadvertently by the CEO.
According to the project's Offshore Petroleum Proposal, the scope 1-3 CO2 emissions equate to some 878 million tonnes of CO2. The field itself has a very low CO2 content of 0.1%.
How did O'Neill - long known for her acute attention to project detail after years of working as the company's chief operations officer - come up with such a different figure?
EnergyQuest CEO Dr Graeme Bethune declined to comment in detail today, but did say that he wasn't sure how Woodside would be calculating scope 3s given it didn't know the end point for use of its gas by portfolio buyers like RWE.
In February it signed a seven-year agreement for supply of 840,000 tonnes per annum.
The Australia Institute principal advisor Mark Ogge told Energy News that the 878MMt figure is being quoted in isolation from the rest of the project.
"Scarborough gas isn't the only gas going to Pluto," he said.
Pluto's Train 1 is fed by the Pluto fields, although Woodside management has been clear scopes 1 and 2 emissions have been offset since the project's first days in 2014.
O'Neill said at the APPEA conference this year that it had offset carbon pollution from Pluto via planting 3.6 million trees last year.
The CCWA and TAI report notes that the 1.6 billion tonne figure comes from the development of Scarborough field's 1.1 trillion cubic feet of gas, as well as the emissions from the expanded Pluto LNG facility, which will also receive gas from the Jupiter and Thebe reservoirs, as well as onshore gas and be connected to the Karratha Gas Plant up the road.
The company also has an agreement in place to send some Pluto gas as backfill to the North West Shelf.
These fields will come online later in the life of the project and offer "future tie-back opportunities" according to a Woodside statement from April this year.
Woodside CEO Meg O'Neill
Last week O'Neill said it was searching for backfill for both Pluto Train 1 and the North West Shelf.
"We are very keen to keep the plant as full as we possibly can... The North West Shelf joint venture continues to actively solicit gas from other potential shippers and so there is more conversations in that way. But the current terms that have been agreed are for that limited time period from Pluto," she told a teleconference call.
Scarborough gas will fill the new Train 2, keeping it running at 5MMtpa, while Train 1 will run at 2MMtpa and then 3MMtpa of its 4.9MMtpa nameplate, meaning the actual new LNG capacity added to Australia will not be 5MMtpa but only 3MMtpa.
"What we're talking about is the Pluto expansion of both 1 and 2 and the interconnector, so we use the capacity for all of them, over the 31 years of the project's life and we use the same LNG carbon intensity as Woodside," Ogge said.
Forecast Scope 1 and 2 emissions from current and future project assets are estimated to be 15.9 million tonnes per annum CO2-e, increasing from the current 9.6MMtpa for the NWS project and Pluto LNG, Woodside has said.
It has said that the combination of new technology at Pluto Train 2, and a low CO2 reservoir will make the Scarborough development one of the lowest in carbon intensity, beating even Qatar.
A Woodside spokesperson did not respond to questions about how its emissions figures were divided.
Ogge noted O'Neill was "probably quoting our number, which is good because Woodside hasn't published any estimate on the total emissions of the Pluto expansion".
CCWA announced yesterday that it had launched a second legal action against Woodside and the state government, asserting that the existing works approval for expansion of the Pluto facility, issued by the state's CEO of the Department of Water and Environmental Regulation was unlawful as it failed to properly consider and control the environmental harm generated by the development's greenhouse gas emissions
