Over the last 12 months, professional anti-gas campaigners have shut down drilling and seismic survey programs across Australia's offshore sector by utilising the judicial system. While these activists have won two lawsuits delaying development of gas projects, they have also thrown into disarray urgent environmental decommissioning activities.

The first challenge was won by the Environmental Defenders Office (EDO), which is partially funded by the government. The EDO was representing Tiwi Islander Dennis Tipakalippa, who claimed he was not adequately consulted by Santos before it received drilling approvals for the $4.7 billion Barossa project. The court upheld this claim late last year, and drilling was abruptly halted.

Then, in recent months, Woodside lost a similar court case over its seismic program at the Scarborough gas fields. This challenge was brought by activist-native-titleholder Raelene Cooper who also claimed to have not been consulted, despite having been offered fortnightly meetings with Woodside management. Cooper was also represented by the EDO.

The activists behind the legal battles, including Disrupt the Burrup Hub, Greenpeace, Save Our Songlines and Extinction Rebellion, have celebrated their wins. The court findings have ramped up project costs by hundreds of millions of dollars, delayed development activities, and caused significant complications for Santos and Woodside's respective management.

A second, less understood, outcome is that the federal court decisions have tied the hands of the national regulator in approving any, and all, activities. This includes decommissioning of offshore oil and gas wells, production platforms and other infrastructure.

Australia faces a tidal wave of decommissioning liabilities over this decade and the next in the region of US$40 billion.

There are currently dozens of applications from the offshore energy sector pertaining to work programs which are sitting in limbo. The applications range from seismic programs, infill drilling activities, laying pipelines, et al.

These environmental plans seem to stuck in the mud as the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) comes to terms with the Court's findings.

Critically, the plans before NOPSEMA include decommissioning of legacy oil and gas fields in the North West Shelf and the Bass Strait.

Earlier this year, ExxonMobil advised it had spent nearly $1 billion in early decommissioning workers over the last five years. It has billions of dollars' worth of additional liabilities needing to be completed in the short term. However, obtaining approvals is likely to be a drawn-out process.

On the North West Shelf, Woodside has been struggling to remove a riser turret mooring unit. The RTM was once connected to the Nganhurra floating production storage offloading (FPSO) vessel.

It has been floating offshore for years and became a controversial piece of infrastructure when activist group Greenpeace climbed it.

Protesters scaled the RTM and secured a banner reading "Woodside, don't be a tosser" calling on the company to remove it.

However, in a recent document from NOPSEMA, concerns were raised that the very legal outcomes cheered by Greenpeace to stop development approvals has now impacted decommissioning of the RTM.

NOPSEMA had previously issued a direction to Woodside ordering the company to quicken its pace and drag the RTM onshore for decommission. This month, NOPSEMA director Cameron Grebe issued a variation to the direction.

The direction states that the decision by the Federal Court in the matter brough by Raelene Cooper against Woodside, "there is uncertainty as to whether NOPSEMA's decision [to approve the removal of the RTM] is valid, and whether the environmental plan is valid and operative."

NOPSEMA already holds grave concerns over RTM - which had to be re-floated - after sinking below the ocean surface.

It said it had "concerns about the structural integrity" of the unit and needed to be lifted onto a platform and towed to shore imminently to "avoid further deterioration" which could see it sinking again. Around the corner is the cyclone season.

The variation to the direction acknowledged that while the environmental plan submitted by Woodside and previously approved to remove the RTM may be invalid.

However, NOPSEMA said "the risks posed by not removing the RTM as soon as possible outweigh any other matters" and that Woodside should proceed. 

Energy News approached NOPSEMA for comment.