It’s time we unlocked the sustainability potential of our infrastructure projects

Arcadis develops world leading sustainability design integration for mobility projects

By Ken Lunty – Technical Director, Sustainability – Arcadis Australia

What if you could visualise the life cycle carbon footprint of infrastructure design before committing to a decision? How would that influence the design and procurement process to include more than the traditional criteria of program and capital cost, but also about whole of life environmental, social and economic factors?

The transport and infrastructure sectors are amongst the largest emitters of greenhouse gas in the world.  As renewable energy infrastructure continues to develop, electric vehicles will eventually contribute to decarbonisation in transport infrastructure. But the roads on which they run are still being designed, built and maintained in without decarbonisation front of mind.

It’s a common-sense approach to infrastructure design that has yet to be applied in Australia, or really anywhere in the world.

At Arcadis, we take our commitment to sustainable design seriously and have developed a simple method to embed sustainable decision making into our design processes.

For any major mobility project, our designers are typically required to deliver according to the client’s technical criteria. This details the design requirements across all our disciplines. While our different disciplines are excellent at coordinating the design and delivery of a project, sustainability assessment is traditionally undertaken in isolation and late in design. Usually too late to make any changes –a wasted opportunity.

As an example, pavement design and sustainability strategy are typically delivered independently and then bolted together as an afterthought. Additionally, the optimisation of design usually focuses on replacing virgin materials with recycled ones. This is a specification focused approach rather than a life cycle approach on holistic performance. We cannot capture the full sustainability impacts of a design through the narrow lens of recycled materials and capital cost. This doesn’t go far enough.

We’re taking a more holistic approach and have aligned our civil and sustainability design outcomes so that we can clearly articulate the sustainability impacts of specific design choices to our clients before committing to a pathway forward.

This is not a complex exercise, however it is a detailed one. We’ve been inspired by the nutritional labels you find on products in the food sector. These explain what you are putting into your body or where ingredients come from. We have applied this to the design and construction of mobility projects. At a glance, we can see how different designs compare across various criteria to inform better designs and sustainable outcomes or put simply ‘a metric of scaled sustainability’. This makes sustainability visible, and accessible to all project decision makers.

Let’s continue with the pavement example. We undertake a life cycle assessment which can cover raw materials, manufacturing, installation, maintenance, demolition and end of life. Using industry recognised and standardised assessment methodologies, we quantify the sustainability outcomes of different pavement design options – including current standard design options as well as alternative, innovative ones developed with sustainability considerations.

We’ve seen an immediate benefit of this approach on a major infrastructure project in Australia. We conducted an assessment of the singular pavement design permitted by the client as part of a larger project. The long-term sustainability outcomes were one of the worst for the project – around 7.4kg CO2 equivalent emissions per square metre of pavement per year of design life. We assessed a range of different options and developed a pavement design that reduced CO2 emissions by 35% on a mainline road. Using the same approach, we were also able to identify a 75% reduction in life cycle carbon for a shared user path. This out of scope design was accepted by the client based on its holistic advantages over the reference design.  

By making sustainability visible in the tender stage and communicating this to the client clearly and simply, we have been able to create a positive impact on the project and were ultimately successful in tender and setting a precedent for use of more sustainable design options in future.

When we’re talking about carbon emissions, it may seem like kgCO2/m2/year is a drop in the ocean However, these are isolated pavement designs in a sea of asphalt and bitumen. Consider that Australia has around 800,000km of road – of which 310,000km is surfaced. Annual production of asphalt is about 10 million metric tonnes per year. Annual use of bitumen is more than 800,000 metric tons. We hope to create a wave of change in this ocean of opportunity. Every small reduction in the life cycle carbon emissions has the potential to scale up to a significant overall saving. Every small reduction helps us move closer to net zero. We can do better.

As we continue to add more data, our simple assessment tool will help to automate and quantify the long-term sustainability outcomes. We have now used this approach on seven major projects in Australia. For our pavement design team, it’s business-as-usual and our clients have embraced the ability to assess design options side by side.

We are already investing in a wide variety of assessment techniques to scale this assessment tool to all mobility and place making design elements. The assessment will also expand to include social and financial measures, including maintenance closures, resilience and life cycle cost.

While Arcadis is leading the way, we believe this focus on sustainability should be the standard on all infrastructure projects. To support this, we are also developing benchmarking, working with industry to develop performance-based specifications to unlock new opportunities for material re-use, and extending life cycle assessments to include use and demolition phase impacts.

Recent guidance from industry has proposed the introduction of a carbon base case for infrastructure projects and programs over $100m capex. Specifically, this carbon benchmark is recommended to be developed at the planning phase – before it becomes shovel ready This would allow for the embedded carbon to be included in the assessments of bids along with conventional metrics.

The transport and construction sectors are heavy emitters. However, armed with the right information at the right time, we can make better design decisions which will have long-term sustainable benefits. This is the future of infrastructure design.

For further information contact:

Rebecca Hanlan, Head of Communications, Arcadis
M +61 499 278 120
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