Heavily-redacted documents posted to the Department of Water and Environment‘s Freedom of Information disclosure logs show excerpts of Woodside's conversations with the department regarding its draft Environmental Impact Statement for Browse, which was put together throughout 2018 and published in December 2019. 

The field has always been known to be high CO2 at some 10% of reservoir gas and the initial plan was to vent it for the first few years of production and then look to CCS. Currently the company prefers offsets via tree planting over sequestration. 

However after sanction of the project was pushed back yet again last year, Coleman said during a March earnings call that CCS could be performed from the start up of the project, and at no real extra cost "but I'd hate to say that to a regulator". 

Given the calls' transcripts appear on both Woodside's own website and the ASX the regulator could read this, and it has prompted some official bemusement after the company privately lobbied so hard to underline the difficulty and costs it said would be associated with Browse CCS from the get go. 

The documents highlight multiple CCS methods Woodside could potentially use for offsetting emissions at EPBC 2018/8319, stating Woodside's current proposal is to provide space on board the FPSO to install facilities to reinject reservoir emissions at a future date. 

However the draft EIS says that to do so would have a "high technical, operational and safety risk, due to the offshore environment at the Calliance reservoir." 

"[CCS] is significantly complex due to gas turbine exhaust capture being an unusual geosequestration technique" and is "not cost effective when compared with approved carbon farming methodologies used to offset emissions". 

Woodside states that "geo-sequestration is presently a high risk, high cost mitigation option for Browse reservoir CO2 and is not proposed in the draft EIS."

"CCS opportunities will continue to be monitored and assessed as the technology is likely to improve in the future." 

Coleman said at the 2019 APPEA conference gas turbine exhaust capture was tricky and in former operational roles he'd had experience with flue gas. He was also clear CCS needed a proximate and suitable reservoir. 

"We're looking at options now around sequestration not just in the immediate field area but other aquifers some distance from Browse," he said last March. 

He estimated a cost "just north" of A$100 per tonne.

"The key thing for Browse is that the further it goes out, then the more likely that... sequestration will be part of the base plan for Browse," he said.

Browse is now so far out and yet the technology to make CSS for it feasible has yet to appear. 

At the annual general meeting just before Coleman stepped down as CEO, he said further work had been done and the company was looking at a series of sites within a 160km radius of Karratha, where its onshore gas plant is. 

Woodside, he said, had one onshore option in mind and several offshore, including the currently producing Angel field that is part of the wider North West Shelf joint venture. All of these options are very far from any FPSO installed at the fields. 

"On face value, this approach does not appear consistent with the public remarks made by the WEL CEO regarding carbon sequestration for the Browse project," NOPSEMA

However the documents show the department was not enamoured by the CEO's March comments given how hard Woodside has lobbied against CCS and the very public boot he took to the WA Environmental Protection Authority when in 2019 it suggested all new projects offset all emissions from the get go. 

The department also points to statements on Woodside's website posted in April last year, where the company said it  had "a commitment to offset equity reservoir CO2 emissions across our global portfolio from 2021".

"On face value, this approach does not appear consistent with the public remarks made by the WEL CEO regarding carbon sequestration for the Browse project," the offshore regulator (NOPSEMA) concluded. Both the federal NOPSEMA and the state agencies oversee the project given production is in Commonwealth and state waters. 

The department's comments note the EIS should be revised to address Coleman's public remarks relating to CCS or require that outcome-based conditions that ensure the engineering designs allow space for CCS should it become a "feasible and appropriate" option for reducing emissions be included. 

The documents discuss multiple methods for CSS, including capturing CO2 either before or after combustion or via a process known as oxyfuel combustion, where fossil fuels are processed in a nearly pure oxygen environment, as opposed to air - with the oxygen separated from the air prior to combustion. 

However it states post-combustion is preferred for its near-term applicability due to its ease of retrofitting to existing power plants and operations flexibility of switching between capture and no-capture modes.

An unnamed department official wrote in the documents that they were "interested to know what firm commitments Woodside may be contemplating including in the final EIS to reflect this". 

"Commitments should ideally be specific, have measurable outcomes and be included in the final EIS for the project to ensure they are able to be accounted for through the formal assessment of the project," they wrote. 

Coleman announced his departure earlier this year and is set to step down from the board next month. 

A Woodside spokesperson did not respond to Energy News' questions as to why Coleman made the remarks, and said whilst CCS does not feature under the draft EIS "the feasibility of CCS is being further investigated and work is being carried out to mature understanding of the technical and commercial uncertainties and risks specific to Browse".

"The Browse Joint Venture (BJV) has submitted its Response to Submissions document (State) and EIS Supplement (Commonwealth) to address public issues/comments. These documents will be made public once reviewed and accepted by the regulators," they said. 

Previously released FOI documents on the Browse draft-EIS shows the federal department found multiple issues with the document, saying it failed to adequately consider key issues around the project's impact on endangered marine life, oil spill events, the decommissioning process, greenhouse gas emissions and even the projected LNG demand it uses to justify the project.

The documents on Browse CCS are availiable on the Department's website and can be found here.