Western Australia introduces new regulatory framework for Greenhouse Gas Storage

Western Australia has taken a significant step towards enabling carbon capture and storage (CCS) projects, with two new sets of regulations commencing on 28 May 2026.

The Petroleum and Greenhouse Gas Storage (Submerged Lands) (Greenhouse Gas Injection and Storage) Regulations 2026 (WA) and the Petroleum, Geothermal Energy and Greenhouse Gas Storage (Greenhouse Gas Injection and Storage) Regulations 2026 (WA) (together, the GHG Regulations) establish a comprehensive framework governing the assessment, approval, and long-term management of greenhouse gas (GHG) storage projects in Western Australia.

Introduced by the Petroleum Legislation Amendment Act 2024 (WA) the GHG Regulations detail:

• Declarations: comprehensive requirements for the submission and assessment of applications for the Minister to declare a formation wholly within the area of a holder's existing onshore or offshore GHG, petroleum or geothermal permits/licences/leases as an "identified GHG storage formation" (Schedule 1);

• site plans: comprehensive requirements for the submission and assessment of draft site plans for that GHG storage formation (Schedule 2); and

• compliance and review: ongoing compliance obligations, including in relation to approved site plans, which must be reviewed at least every five years or upon the occurrence of certain triggers (sections 30-34).

The GHG Regulations form part of a broader package of reforms intended to facilitate CCS development in Western Australia. For proponents, these regulations are significant because they establish the detailed technical, operational and compliance requirements that will determine how CCS projects are assessed, approved and managed throughout the project life cycle.

What does Western Australia's GHG storage regime look like?

The GHG Regulations complement the legislative framework introduced by the Petroleum Legislation Amendment Act 2024 (WA) (PLAA), which also commenced on 28 May 2026.

The PLAA amended the Petroleum, Geothermal Energy and Greenhouse Gas Storage Act 1967 (WA) (PGGSA) and the Petroleum and Greenhouse Gas Storage (Submerged Lands) Act 1982 (WA) (PSLA) (together, the Amended Acts), creating parallel regulatory regimes for GHG storage operations in onshore Western Australia and offshore territorial waters.

Previously, the injection and permanent storage of GHG within WA was only regulated on a project-specific basis for the Gorgon Project under the Barrow Island Act 2003 (WA).

The new framework introduces a dedicated approvals pathway for CCS projects within Western Australia’s existing legislative framework. A key benefit of this approach is that many aspects of the regime will be familiar to proponents already operating petroleum or geothermal projects under Western Australia's existing framework, or undertaking GHG storage activities in the Commonwealth offshore area under the Offshore Petroleum and Greenhouse Gas Storage Act 2006 (Cth).

Applications for the siting of CCS projects

The amended legislation establishes a framework for identifying an "eligible GHG storage formation" and declaring an "identified GHG storage formation" wholly within the area of a holder's GHG exploration permit, GHG drilling reservation, GHG retention lease, GHG injection licence, petroleum production licence, petroleum retention lease, geothermal retention lease or geothermal production licence. To qualify as an "eligible GHG storage formation," a geological formation must be capable of storing at least 100,000 tonnes of a GHG substance and must satisfy prescribed "fundamental suitability determinants." These include the existence of an "effective sealing feature or attribute" that enables the permanent storage of the relevant GHG substance.

Where a titleholder reasonably believes a geological formation within its title area satisfies those criteria, it may apply to the Minister for a Declaration identifying the formation as an identified GHG storage formation.

The application must not only demonstrate why the formation qualifies as an eligible GHG storage formation but also include detailed supporting information addressing its suitability for long-term GHG storage. This includes data on the formation's injection characteristics, containment capacity, and estimated spatial extent.

Prior to the introduction of the GHG Regulations, there was limited subordinate guidance regarding the scope and detail of information required to support such applications.  The GHG Regulations now address this gap by establishing a prescriptive disclosure regime that sets out clear requirements for the information proponents must gather and submit.

What do applications to the Minister require?

Schedule 1 to the GHG Regulations imposes substantial requirements on proponents seeking a Declaration, mandating predictive capabilities regarding the behaviour of GHG substances and the long-term integrity of storage operations. For proponents in the early stages of project development, these requirements effectively outline the work program that must be completed during the exploration phase. Key requirements include:

Detailed subsurface assessment

Proponents must provide a comprehensive assessment of the proposed storage formation, including information relating to:

• stratigraphy;

• faults and structural features;

• porosity and permeability;

• geomechanical characteristics;

• fluid behaviour;

• seismicity;

• exploration history; and

• existing wells.

Proponents must also prepare and submit three-dimensional geological and dynamic reservoir models, together with assessments of potential migration pathways and sealing features.

Risk assessment and management

Proponents must identify and assess risks associated with long-term GHG storage, including risks relating to containment integrity, fluid migration and storage performance. The GHG Regulations also require proponents to demonstrate that risks have been reduced to as low as reasonably practicable (ALARP).

Where engineering measures are proposed to enhance storage performance or mitigate risks, such as well remediation, pressure management, or injectivity improvements, these measures must be supported by robust technical analysis.

What is the assessment process for Declarations?

The assessment process aims to provide flexibility, allowing proponents to refine their submissions through Ministerial engagement rather than facing a strict pass/fail outcome. If the Minister identifies deficiencies in an application but believes they can be addressed, proponents will be given an opportunity to revise their submission to meet the necessary requirements.

Are site plans required?

Once a Declaration is in force, titleholders can apply for a GHG retention lease or GHG injection licence over the declared area if not already granted. However, operations cannot commence without an approved site plan for each identified GHG storage formation covered by the licence. Non-compliance is an offence carrying a maximum fine of $10,000.

Existing GHG licensees and applicants for a GHG injection licence must submit a draft site plan to the Minister for approval. Approved site plans take effect immediately and remain in force indefinitely unless withdrawn by the Minister.

What are the Schedule 2 requirements for site plans?

Part 3 and Schedule 2 of the GHG Regulations prescribe detailed requirements for draft site plans. These requirements are divided into two parts.

What does the assessment process look like?

The Minister may approve or refuse a draft site plan and may impose conditions on any approval.

Consistent with the broader framework, the assessment process is intended to be iterative. The Minister may request additional information or invite revisions to a draft site plan prior to making a decision.

Although the GHG Regulations require the Minister to be "reasonably satisfied" that the prescribed requirements have been met, the Minister retains broad discretion to consider any other matter considered relevant. This residual discretion allows project-specific concerns to be addressed as part of the approval process.

Do site plans need to be reviewed and updated?

Approved site plans must be reviewed at least every five years or when a mandatory review trigger occurs. These include situations where new information materially alters assumptions relevant to storage suitability or migration pathways, or significant operational changes are proposed.

The review process must consider matters including:

• operational experience since approval;

• the accuracy of Part A predictions;

• monitoring and migration pathway data; and

• developments in industry standards and technical practice.

Following each five-yearly periodic review, licensees have 30 days to notify the Minister whether a variation to the site plan is required, and if so, must submit a draft variation to the Minister within 180 days.

Following a trigger event review, the proponent must submit a draft variation to the Minister within 60 days of that trigger event occurring.