East Coast Supply Project - Wells Connection Environment Plan

The East Coast Supply Project (ECSP) intends to help meet East Coast domestic gas demand by developing subsea gas reserves to replace existing wells as they run out. Imported alternatives cost significantly more and cause much higher emissions. Under the ECSP—Wells Connection Environment Plan, production wells will be tied into our existing subsea pipeline to allow hydrocarbons to be transported to our Athena Gas plant. 

Update log

• March 2025: Page created

Location

Adjacent to the Athena gas plant, Otway Basin, 9km offshore Peterborough and Port Campbell, Victoria. 

Offshore Eastern Maar Sea Country.

Activity details​

We plan to:

• Modify existing subsea equipment
• Install flowlines and umbilicals
• Test and commission the system
• Operate vessels
• Undertake inspection, maintenance and repair of the flowlines and / or umbilicals
• Survey the seabed

Distance from shore

Approximately 9km from shore at the closest point.

Permit areas

• VIC/L24
• VIC/P76
• VIC/P44
• VIC/L30

Water depth

Approximately 55 to 80 metres

Supply base

Portland 

Summary of Impacts, Risks and Activities

Information sheet  regarding impacts, risks and control measures.

Timeline

Wells connection: The expected duration for activities is ~120 days. Installation activity window is 2027 - 2030. 

IMR and survey:  The expected duration is ~60 days per campaign. Window is 2027 - 2030.

Identified impacts and risks

Interaction with Other Marine Users

Our proposed activities offshore that may result in interaction with other marine users include:

• Vessel operations including safety exclusion zones
• Petroleum Safety Zone around equipment (if needed)

Impact

• Change to the functions, interests and activities of other marine users.

Controls

To mitigate or reduce the impacts and risks of our activities we will:

• Implement a Marine Assurance Process (e.g. comply with AMSA Marine Orders)I
• Communicate exclusion zones around vessels via Notice to Mariners
• Gazette any PSZ around equipment where required for equipment integrity management
• Mark subsea infrastructure on navigational charts for awareness
• Implement a Fisheries Damages Protocol
• Undertake ongoing engagement including notification of third party stakeholders

Seabed disturbance

Our proposed activities offshore that may result in seabed disturbance include:

• Installation of flowline and umbilical systems on the seabed
• Post-lay works and commissioning (discharges)
• Possible anchor placement for our operating vessels in bad weather
• ‘Flying’ our ROV (remotely operated vehicle) close to seabed

Impact

• Change in benthic habitat (sediments at the bottom of ocean).

Risks

Include possible:

• Marine fauna injury or mortality
• Cultural heritage changes.

Controls

To mitigate or reduce the impacts and risks of our activities we will:

• Use available seabed survey data to identify and avoid sensitive benthic features and potential underwater cultural heritage
• Implement Offshore Operational Procedures
• Implement an Underwater Cultural Heritage Disturbance Risk Management Process

Underwater sound

Our proposed activities offshore that may result in changes to underwater sound include:

• Operation of offshore vessels 

Impact

• Change in ambient sound

Risks

• Change in fauna behaviour 

Controls

To mitigate or reduce the impacts and risks of our activities we will implement:

• Marine Assurance Processes e.g. planned maintenance of power systems
• Offshore Operational Procedures e.g. helicopter and vessel distances around cetacean
• Offshore Whale Disturbance Risk Management Process to ensure our activities are not inconsistent with relevant EPBC species recovery plans

Greenhouse gas emissions

Our proposed activities offshore that may result in GHG emissions include:

• Vessel operations

Impact

• An increase in GHG emissions

Risks

• Change in climate and marine systems
• Change in ecosystems
• Change in socio-economic factors

Controls

To mitigate or reduce the impacts and risks of our activities we will implement:

• Marine Assurance Process (e.g. vessel AMSA marine order compliance)
• Emissions Management Process (e.g. identify, assess and implement emissions reduction opportunities)

Light emissions

Our proposed activities offshore that may result in light emissions include:

• Vessel operations

Impact

• Change in ambient light

Risks

• Change in fauna behaviour

Controls

To mitigate or reduce the impacts and risks of our activities we will:

• Conduct a pre-campaign risk review for light
• Implement Marine Assurance Process (e.g. comply with Marine Order 30)
• Implement Light Management Measures (e.g. Vessel non-essential light positioning)

Other atmospheric emissions

Our proposed activities offshore that may result in Atmospheric Emissions include:

• Vessel operations
• Helicopter operations
• Installation and commissioning of flowlines

Impact

• Change in air quality

Controls

To mitigate or reduce the impacts and risks of our activities we will:

• Implement a Marine Assurance Process for vessels

Planned discharges

Our proposed activities offshore that may result in planned discharges include:

• Vessel operations
• Installation of subsea structures
• Maintenance and repair

Impact

• Change in water quality and change in sediment quality.

Risks

• Injury / mortality to marine fauna.

Controls

To mitigate or reduce the impacts and risks of our activities we will:

• Implement a Marine Assurance Process
• Implement an Offshore Chemical Assessment Procedure
• Ensure the vessels meet emissions and discharge standards  prior to commencing an offshore activity
• Undertake a campaign risk review 

Invasive marine species

Activities

• Ballast water adjustments by vessels to maintain stability.
• Biofouling by vessels through IMS presence on submerged surfaces

​​Risks

• IMS transferred into field, establishes and spreads.
• IMS is transferred between vessels, establishes and spreads to other areas.
• IMS is transferred out of the field and establishes outside the region and spreads.

Controls

• IMS Risk Management Protocol
• Australian Biofouling Management Requirements

Unplanned interactions with marine fauna

Our proposed activities offshore that may result in unplanned interactions with marine fauna include:

• Vessel operations

Risks

• Injury / mortality to marine fauna.

Controls

To mitigate or reduce the impacts and risks of our activities we will:

• Implement Offshore Operational Procedures (e.g. distances and management practices for interacting with cetaceans)
• Implement an Offshore Victoria Whale Disturbance Risk Management Procedure to ensure our activities are not inconsistent with relevant EPBC species recovery plans

Accidental hydrocarbon release

Our proposed activities offshore that may result in accidental hydrocarbon release include:

• Vessel operations

Impact

• Change in water quality

Risks

• Change in Habitat
• Change in Fauna Behaviour
• Injury / Mortality to Fauna
• Changes to the Functions, Interests, or Activities of Other Users

Controls

To mitigate or reduce the impacts and risks of our activities we will:

• Implement a Marine Assurance Process (e.g. compliance with Marine Orders)
• Implement Marine Exclusion and Caution Zones
• Undertake ongoing engagement
• Maintain an Operational and Scientific Monitoring Program
• Have an accepted Oil Pollution Emergency Plan for the activity
• Have regulatory Safety Management Plans in place

Loss of Materials or Waste Overboard

Our proposed activities offshore that may result in Loss of Materials or Waste Overboard include:

• Installation of flowlines and umbilicals
• Vessel operations
• ROV operations

Risks

• Change in Habitat
• Injury / Mortality to Marine Fauna
• Change to Cultural Heritage

Controls

To mitigate or reduce the impacts and risks of our activities we will:

• Implement a Marine Assurance Process
• Implement Offshore Operational Procedures
• Ensure Vessels meet Emissions and Discharge standards

Have your say

We want to hear from relevant persons. Please use the contact form below to get in touch, and feel free to share this website link with any other relevant persons that you are aware of.

What next

We will submit our draft environment plan to the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) for assessment. If you have consulted with us as a relevant person, your input will be considered in improving our EP. Your name will be included in the "sensitive information" part of our plan and not published.