Seeding new ground in sustainable construction

As the race to net zero and climate goals intensify, the transport and infrastructure sectors are primed for transformation.

Infrastructure Australia estimates that around 70 per cent of carbon emissions are directly and indirectly influenced by the infrastructure sector, presenting both a challenge and an opportunity for change.

Infrastructure construction activity is projected to add between 37 and 64 million metric tons (Mt) of embodied carbon each year for five years to 2027, with transport infrastructure including rail among the largest contributors. However, Infrastructure Australia also reports that by employing practical decarbonisation strategies, nearly a quarter of these emissions could be reduced by 2026-27.

Gamuda is tackling these challenges head-on with a commitment to environmental, social and corporate governance outcomes. As part of its ambitious Gamuda Green Plan 2025, the company has pledged to reduce Scope 1 and Scope 2 emissions intensity by 30 per cent in 2025 and 45 per cent in 2030, with the ultimate goal of net zero by 2050.

In Australia, Gamuda has adapted this plan to local conditions through its Seeds for Growth initiative, a sustainability framework that emphasises circular construction, collaboration, empowerment, and responsible business.

Describing the company’s approach, Hayley Young, Gamuda’s Head of Environment and Sustainability, said, “we’re committed to fundamentally transforming how we approach construction. Every project provides an opportunity to reduce our carbon footprint, and we’re proactively implementing cutting-edge solutions to help lead the industry into a more sustainable future.”

Leading the Way in Infrastructure Sustainability

One of Gamuda’s most noteworthy achievements in sustainable construction is the Infrastructure Sustainability (IS) Rating awarded by the Infrastructure Sustainability Council (ISC) for its Sydney Metro West – Western Tunnelling Package (WTP). This industry-recognised rating assesses infrastructure projects on their economic, social, and environmental performance throughout the project lifecycle.

The Gamuda and Laing O’Rourke Consortium (GLC) achieved a ’Leading‘ rating with a score of 96.8 out of 110. The consortium was also recently a finalist for the ISC’s 2024 Excellence in Environmental Outcomes Award.

Young explained, “Achieving a ‘Leading’ rating for our first project is a testament to our team’s dedication to embedding sustainability into every aspect of our project design and delivery. The IS Rating helps us benchmark our progress, pushing us to continually improve our environmental impact.”

Innovations in Tunnelling: Autonomous Technology and Energy Efficiency

A core innovation on the Sydney Metro West – Western Tunnelling Package is the deployment of Australia’s first autonomous Tunnel Boring Machines (A-TBMs), developed by Gamuda. These machines utilise advanced sensors, control systems and artificial intelligence (AI) to operate autonomously, which leads to an 8 per cent energy savings compared with traditional TBMs. This reduction translates to 2,587 MWh of power savings and 2,001 metric tons of CO? equivalent emissions abated across the project.

“These A-TBMs are game changers,” Young said. “With their advanced technology, we’re not only improving productivity but also making a tangible impact on reducing our energy footprint. It’s a powerful example of how innovation can drive sustainability in construction.”

Material Efficiency with the Precast Segment Mix

GLC is also advancing sustainable construction through an innovative precast segment mix developed in collaboration with Boral. This new mix, used for lining the tunnels, incorporates approximately 50 per cent supplementary cementitious materials and contains 10 per cent less total cementitious content without sacrificing its technical requirements. This innovation is expected to reduce overall emissions by 12,000 metric tons of CO? equivalent by the end of the project.

“Concrete production is a significant source of emissions in construction,” Young noted. “By rethinking our materials and collaborating with industry partners, we’re driving down the embodied carbon in our projects and setting a new standard for sustainable construction.”

Water Conservation: A First for Tunnel Boring Machines in Australia

In line with the project’s sustainability goals, the Water Treatment Plant at Clyde has been designed to recycle groundwater and rainwater while meeting the water quality requirements for Tunnel Boring Machine operations set by their manufacturers. To date, this system has conserved over 110,000 kL of potable water, making it the first project in New South Wales to use treated groundwater for TBM operations.

“We’re proud to be the first in Australia to integrate recycled water on such a scale for tunnelling,” Young said. “It’s about creating a sustainable model that conserves resources without compromising project needs.”

Renewable Energy: Solar Hybrid Generators

To further reduce emissions, GLC and Black Stump Technologies deployed solar hybrid generators for the project’s Tunnelling and Infrastructure Academy, which was set up to train existing and new construction workers. This rapidly deployable system generates 521 MWh of carbon-neutral electricity annually, avoiding 276 metric tons of CO? equivalent emissions and cutting diesel costs.

“Renewable energy is essential in our mission to decarbonise,” Young highlighted. “The solar hybrid generators are a pioneering move in the construction space, and the success of this deployment shows that renewable options are not only feasible but can be scaled efficiently.”

Setting the Standard for Responsible Business

Gamuda’s Seeds for Growth framework as part of its Green Plan 2025 is representative of the organisation’s commitment to sustainable construction in Australia. By combining industry-leading technology, efficient materials, water conservation and renewable energy, Gamuda is reducing emissions and setting new industry benchmarks that can be employed on future rail infrastructure projects.

Reflecting on the broader impact of these efforts, Young says: “For us, sustainability is more than meeting a target—it’s about transforming how we build and ensuring that every project leaves a positive legacy. We hope to inspire others in the rail industry and beyond to adopt similar practices and work together to meet Australia’s emissions reduction goals.”