Sustainability
Sustainability is a key feature of the M4 and M8 extensions and has been embedded into the design, construction, and the operation of the motorway to enhance environmental and social practices and outcomes in the local community.
Through our Power Purchase Agreement with CWP Renewables, the Bango and Sapphire wind farms will provide renewable energy to meet at least 80% of the energy needed to power the entire WestConnex motorway.
Reducing Our Carbon Footprint
The M4 and M8 extensions has also contributed to a range of United Nations Sustainable Development Goals (SDGs). Overall, carbon emissions during construction and future operation of WestConnex have been reduced by 1,379,364 tonnes, which is around 73% of forecast emissions throughout the project lifecycle.*
* Calculation based on Round 1 Infrastructure Sustainability As Built rating submission, which calculates the emission reduction from the project’s Base Case over the construction phase and 50 years of operation.
100%
tunnel spoil reused
98%
construction waste is recycled
62%
water is from non-potable sources
15%
reduction in overall quantity of shotcrete used in lining the tunnel - world first innovation
14%
emissions avoided across the asset's lifecyle due to ventilation design
8%
emissions avoided across the asset's lifecyle through lighting design
53%
suppliers and subcontractors within targeted skills and employment areas
15%
recycled asphalt pavement (RAP) used
20%
GreenPower™ for electricity sourced for construction
The project has also significantly reduced lifecycle impacts during construction through careful selection of concrete suppliers. By working with key suppliers with the aim to reduce the embodied carbon emissions, a range of project-specific initiatives were delivered including reducing transport distances, using recycled and alternative materials, designing material use efficiently, and adapting tunnel excavation methods.
The project has achieved 32% SCM (supplementary cementing material) in their concrete mixes which equates to over 35,000 tonnes of waste material that has been diverted from landfill from other industries.
Large motorways are often designed to last for many years, usually from 50 to 100 years or more, and therefore need to be adaptable to global changes over these timeframes. Climate change resilience has been embedded into the motorway at the early design phase to ensure that critical infrastructure is resilient to natural hazards and the changing environment such as projected hotter, drier, and stormier conditions, combined with higher sea levels.
An Infrastructure Sustainability (IS) rating has been implemented across the Design and As Built phases of the project, which is a standardised framework governed by the Infrastructure Sustainability Council (ISC).
The M4 and M8 extension tunnel has achieved a ‘Leading’ Design rating and, the As Built rating is expected to be awarded following opening of the asset.
Find out more about M4 and M8 extensions
History of the M4 and M8 extensions
The new 7.5-kilometre tunnels are a critical component of WestConnex and connect the M4 at Haberfield to the M8 at St Peters. Since site establishment works began in 2018, the project has achieved many significant milestones over the past four years.
Tech-led safety
WestConnex has been built with technology, innovation and safety at the forefront of its construction. Tap on the different icons to learn more about the technology that keeps you safe when travelling in our tunnels.
Hear from the team
Hear from the team that built, operate and maintain the WestConnex motorway.