Q: Lendlease has a bold “Absolute Zero” ambition. What is the difference between “Absolute Zero” and “Net Zero”, and how is electrification helping to lower carbon in buildings?

James Wewer, Lendlease: Our Mission Zero includes both these targets but there are significant differences between the two. Net Zero is about reducing and offsetting any residual scope 1 & 2 emissions in an approved carbon offset scheme. For Lendlease, Net Zero is a milestone but not the ultimate destination. Our Absolute Zero by 2040 target is about working towards eliminating greenhouse gas emissions from our business activities. It applies to Scope 1, 2 & 3 emissions, within the Lendlease defined boundaries and without the use of offsets. It is bold and industry leading but it’s what we believe will drive real decarbonisation across the industry.

Regarding electrification, it’s crucial. We’re trying to electrify our construction practices using electric concrete pumps and cranes, where available, and using battery energy storage systems on sites where there have been grid constraints, to substitute diesel generators. The challenge is around heavy construction plants like large excavators and piling rigs where alternatives to diesel are less commonly available.

And then in operation, when we’re all-electric in our base building, tenancies, food and beverage, and we’re procuring renewable electricity, we can zero out Scope 2 emissions.

The big challenge is electrifying existing stock and retroactively incorporating renewable energy systems into buildings. We’re progressing lifecycle upgrade planning for existing asset infrastructure, conducting technical feasibility and prioritising buildings across our portfolio for all electric retrofit in line with our Mission Zero trajectory.

We’re also continuing our efforts to design out embodied carbon – the emissions associated with the production and processing of materials used in construction, from raw material extraction to manufacturing, transport, installation, and eventual disposal.

Q: What new engineering practices and design approaches are tackling the whole-of-life embodied carbon challenge?

Tai Hollingsbee, GHD: At GHD we focus on understanding a product or building in terms of its total impact — that is, we consider how it will function over a 20, 30, or even 50-year time period.

Things are evolving in the right direction, but not fast enough. What was considered innovative five years ago is now standard practice in the industry, but what’s changed is that the market and clients are now asking for this as a standard service.

To fully consider carbon over a 50-year cycle, it is critical to understand intrinsically what’s in the building. Material passports provide complete transparency about what’s in a building’s component parts — from carpets to light fixtures — including origins and end-of-life destinations. This digital documentation ensures that when your building reaches its end, you’ll know exactly how to handle every material.

Q: What is Sustainability Victoria seeing on the horizon from a more local perspective regarding emissions and embodied carbon?

Paul Murfitt, Sustainability Victoria: We’re strategically looking at the circular economy as a concept, which brings in embodied energy in particular. If you consider our focus on greenhouse gas emission reduction, it’s largely been on energy, such as renewable energy infrastructure, which accounts for about 55% of global emissions. The other 45% is related to the materials we generate, bring into the economy, and often just dispose of at the end of life.

We need to zoom out and interrogate the materials we bring into the economy—how we design them, use them, and whether we should dispose of them.

A good example: in our rush to decarbonise energy, Australia has the highest rate of rooftop solar in the world. However, by 2035, almost five million solar panels will come off roofs and need to be replaced. That’s a waste stream being created now, with all the embodied carbon potentially being disposed of.

The technical solutions for effectively reclaiming all those materials are still emerging, and that’s where research and innovation comes in.

Q: Can you elaborate on the idea of end-of-life reuse and how we can extract greater value from products and materials?

Dr Usha Iyer-Raniga, RMIT: The circular economy is based on three main principles: no waste, no pollution, and allowing the earth to regenerate — it’s specifically about being efficient with the resources we have.

If we don’t think systemically, we end up doing what we’ve done with solar panels, batteries, housing, and buildings. For solar panels, could we design them so that at the end of life all components go back into the production of new panels? That closes the loop.

With buildings, we need to think about what happens when they no longer serve their purpose. How do we use buildings as material banks? To do that, we need to know exactly what goes into the building. This is where initiatives like Material Passports become so critical.

We need to think beyond short-term solutions and take a long-term view of how cities function, how buildings function within cities, as well as the spaces in between these buildings.

Q: What is adaptive reuse and how can we better use aging assets?

James Wewer, Lendlease: Adaptive reuse preserves the structure and heritage of an existing building, upcycling it for a new lease of life.

The City of Melbourne’s initiative, Retrofit Melbourne, found that to reach Net Zero by 2040, the city needs to retrofit 80 buildings per year.

Retrofitting an existing building can have different benefits such as reduction in waste and significant savings in upfront carbon emissions. However not all older buildings can be easily retrofitted to meet current codes, accessibility requirements or energy efficiency standards and may simply not be able to be feasibly upgraded or repurposed.

I think it’s really exciting to look at projects and focus on how we can retain the value of the building and for new buildings, designing for disassembly.