Measurement of embodied carbon emissions is critical if Australia is to deliver sustainable built environment outcomes, leading quantity surveyors say.

During an interview with Sourceable, Niall McSweeney, Head of Development Advisory, Asia Pacific at Altus Group and Patrick Ferreira, Associate at Altus Group, explored the strategies which are involved in the management and measurement of embodied carbon – carbon emissions which occur as a result of building’s material use and construction rather than though its operation.

McSweeney and Ferreira also outlined how the NABERS Embodied Carbon rating tool will drive greater accountability in embodied carbon measurement.

According to McSweeney and Ferreira, the importance of embodied carbon measurement should not be underestimated (see below).

To date, however, McSweeney noted that there has been a lot of reliance of open-source data in embodied carbon measurement. He also suggests that it (embodied carbon measurement) has not been done very accurately has been a bit of guess.

He says that the NABERS tool will add greater accountability to the process and utilises government backed data as well as regulated Environmental Product Declaration (EPD) information.

“What we have to say is that a large portion of the carbon that is emitted over an asset’s lifecycle is emitted during the build process,” McSweeney said.

“At the moment, we are very good at managing energy use during the building’s life in operation (through heating, cooling etc.) because these are readily visible and tie directly into energy consumption. Energy and water use are tangible things which people can readily see. They are metered and translate to dollar impacts.

“However, the embodied side of things is different insofar as people don’t see these things as blatantly in front of them. There isn’t really a tangible financial penalty associated with embodied carbon which demonstrates that people would derive a specific amount of benefit if they were to achieve improvements in this area.

“A lot of what has been done to date is open to interpretation, has not been done very accurately and is a bit of guess. Simply not good enough.

“However, with the new NABERS tool, we’re now going to get it down to the point where it (embodied carbon measurement) is very pointed and clear and it is very evident how you are actually going in regard to embodied carbon performance. It’s going to make a big difference.”

Embodied carbon takes on more focus

The comments come as the importance of embodied carbon continues to grow.

‘Embodied carbon’ refers to carbon emissions which occur as a result of a building’s construction.

It includes emissions that are associated with:

• material use (raw materials extraction, transport to manufacturers and manufacturing)
• transportation to site (materials, machinery/equipment and workers), and
• on-site processes such as equipment or machinery operation.

They are distinct from operational emissions, which occur through use of energy (heating/cooling etc.) over the building’s life.

According to a 2019 report published by the World Green Building Council, embodied carbon emissions in buildings accounted for 11 percent of all energy-related carbon emissions globally.

Whilst this was smaller compared with emissions from building operations (28 percent), the proportion of overall building-related emissions which are attributable to embodied carbon is expected to grow over time as energy grids decarbonise and operational emissions decline.

Why embodied carbon measurement matters

For several reasons, McSweeney and Ferreira say that measuring embodied carbon can be important.

These include:

• Demonstrating achievement of organisational ESG objectives and contribution toward national decarbonisation efforts. As mentioned above, the importance of embodied carbon performance in delivering national sustainability goals and organisational ESG objectives will continue to grow. Increasingly, this is likely to lead to more embodied carbon requirements in public and private tenders for major projects.
• Green star ratings. To achieve Green Star ratings, buildings need to demonstrate a minimum reduction of 10 percent against the reference building. Higher Green Star ratings call for higher percentage reductions in embodied carbon (6 Star is 20 percent). By 2030 all Green Star projects will need to demonstrate a minimum reduction of 40 percent.
• Compliance requirements. Companies increasingly need to measure embodied carbon emissions in order to ensure compliance under the National Greenhouse and Energy Reporting Scheme.
• Mandatory Climate Related Financial Disclosures – The obligations for Mandatory Carbon reporting on scope 3 emissions for groups 2 & 3 start next July. However, Ferreira and McSweeney say that current preparedness for this is lacking.
• Better project outcomes and learnings. Measuring embodied carbon during construction and comparing the outcomes with benchmarks can help to identify areas of project inefficiency such as material wastage or overordering. This can inform learnings for future projects.

New NABERS Tool

The comments come amid the recent introduction of the NABERS Embodied Carbon Rating tool.

Launched   year, the tool enables new buildings as well as refurbishment projects  (provided they meet the criteria) to measure and verify their embodied carbon performance and to compare the results with similar buildings.

It thus provides a certified measure of the outcomes which are delivered in terms of materials, transport and construction processes.

In cases where sufficient benchmark data is available, the tool will deliver a star rating result.

The tool relies upon two sets of data.

In relation to key materials such as concrete, gyprock and reinforcing bar, it requires evidence of delivery and disposal dockets. Regarding concrete, for example, these will include details such as quantity, delivery date, place of origin, strength, type and grade and building element to which it was place (wall, column or slab etc.).

Meanwhile, emissions relating to other, non-key materials can be calculated based on measurements taken from the as-built documentation.

At the end of the process, the tool will provide a measurement of bottom-line embodied carbon emissions as well as a rating which is comparable to benchmarks.

The tool will also highlight how the project has performed along with any areas where there have been deficiencies.

Importantly, the tool is ‘as-built’ in nature and is calculated at project completion based upon data which is obtained during construction. As a result, it reflects the actual physical performance which has been achieved rather than a theoretical result which is based around design.

According to Ferreira and McSweeney, the tool will improve how embodied carbon is measured and managed not only during construction but also throughout the building lifecycle. It will also help to improve efficiency in site activities.

First, it has an extensive list of instructions and requirements which provide clear guidance about how embodied carbon is measured. This is important as embodied carbon measurement practices to date have been subject to varying methods and a lack of accountability in terms of how this is being done.

NABERS also requires assessors to undertake an extensive training course, exam and assessments which are subject to a strict review process.

By highlighting areas where results vary from benchmarks, meanwhile, the tool will assist clients to identify areas for improvement and to learn from these on future projects.

Finally, with its robust data capture processes, the tool is assisting QS firms such as Altus Group and others to inform design teams early on – from project inception and throughout the design process – and to help design teams to establish realistic embodied carbon reduction goals from the outset. This in turn is providing clients with more reliable estimates and confidence when making key decisions.”

Figure 2 AI image via freepix

Myths and facts of embodied carbon

According to McSweeney and Ferreira, misconceptions surrounding embodied carbon measurement and management exist across three areas.

First, embodied carbon reductions are not merely about substituting one product for another.

In fact, when considering substitution decisions, it is necessary to consider not only embodied carbon but overall impacts in terms of project quality, timeframes and costs.

As an example, McSweeney and Ferreira cite the Integrated Mental Health Complex Westmead project near Parramatta in Sydney. When complete, this will be the biggest mental health facility in New South Wales.

On this project, Altus provided embodied carbon assessment services to Richard Crookes Construction during the tender process. Richard Crookes Construction were confirmed as the successful tenderer for main construction in May.

As part of the tender process, the NSW Government had a goal of reducing embodied carbon content by 20 percent.

To achieve this, one strategy that was considered involved a change to the strength and slump content of the concrete. However, careful analysis revealed that this would add several weeks to construction timeframes for each level and months to the overall build.

After identifying this, additional mixes were tested and multiple scenarios were worked through to determine the product that would deliver the best overall outcome.

Another misconception is that ‘timber solves everything’ and that ‘steel is bad’.

Whilst sustainably certified timber can offer advantages from an environmental viewpoint, its use is typically more costly and can create challenges in terms of obtaining fire related approvals.

Meanwhile, steel can deliver reasonable outcomes when used well.

Finally, there is no magic bullet that can be employed at the last minute to reduce embodied carbon.

Instead, embodied carbon should be considered early in design concept.

Success strategies

According to McSweeney and Ferreria, several strategies are needed to derive best possible outcomes.

As mentioned above, embodied carbon needs to be considered in design concept.

Waiting until later to consider embodied carbon both limits the opportunities which are available and increases the costs which are associated with implementing any opportunities.

In the case of the Westmead project, the nature of the development as a mental health building meant that requirements were very strict. As a result, opportunities to reduce embodied carbon during the tender stage were extremely limited.

Had such opportunities been considered during design concept, it is likely that greater outcomes could have been delivered at lower cost.

Next, it is important to understand open-source data and rely upon verified quantities.

As things stand, much advice has been given throughout the industry with limited accountability in respect of the quantities which have been advised.

It is important for quantity surveyors who prepare the quantities to verify that these have been correctly measured in accordance with standards.

With regard to open source data, meanwhile, it is important to understand what you are looking for along with how to apply certain documents such as environmental product declarations with carbon outputs.

It is also important to appreciate that open-source data is generalized in nature. In fact, actual embodied carbon outcomes can vary according to project location, transport distances or any wastage of material.

For this reason, it is important to avoid simply taking open-source data averages and multiplying these by square meters to derive an embodied carbon estimate.

Finally, Ferreira says that quantity surveying firms are well positioned to provide accurate advice.

As the consultants who measure up the building and perform the estimation, quantity surveyors are the source of project data and quantities and are ideally positioned to advise on the quantity aspect of embodied carbon measurement.

With their strong foundational understanding of how the building will be constructed, meanwhile, QSs can also advise on the overall cost and project feasibility implications of any embodied carbon strategies which are proposed.