The Department of Environment recently expanded the Australian Government’s Carbon Neutral Program to buildings, precincts and cities. This is a much-needed move as the construction industry is not yet clearly set on a path to a low carbon future.
While the technology for low or zero carbon buildings is clearly available, the existing building stock is far from achieving this goal. Together with avant-garde projects like Barangaroo and cities like Adelaide and Melbourne setting ambitious carbon neutral targets, the government’s initiative has the potential to establish the concept of carbon neutrality in the whole built environment and initiate significant emissions savings in the near future.
At the current stage, the carbon neutrality initiatives address carbon emissions from major operational processes, such as heating, cooling and transport. But in order to stay in line with Australia’s Intended Nationally Determined Contribution to the Paris Agreement – an economy-wide reduction of greenhouse gas emissions by 26 to 28 per cent below 2005 levels by 2030 – a more holistic approach needs to be pursued by including indirect emissions in targets and strategies.
In the built environment, these are mostly the carbon emissions embodied in construction materials from their production all the way to their disposal or recycling. After all, embodied carbon emissions in the construction sector account for nearly 20 per cent of all carbon emissions in Australia. Therefore, detailed analysis and reliable quantification of embodied emissions of buildings, precincts and infrastructure are a vital part of designing a low carbon built environment and achieving deep emissions reductions.
It is impossible to assess the carbon neutrality of a project without knowing the exact extent of both operational and embodied emissions. Including embodied carbon emissions opens up a variety of additional solutions, from finding less carbon-intense building materials or design structures to planning precincts with a view to smart layout of infrastructure, short distances and efficient transport.
The poor availability of embodied carbon data still constitutes a significant barrier to analyse and pursue such low carbon options. To assist planners and architects in the quantification, software tools are being developed, but the inclusion of embodied emissions in such tools is scant and still an emerging field. Based on a recent scoping study under the CRC for Low Carbon Living, we examined tools available for the Australian market to evaluate and assess how they can help shape a low carbon future.
On the one hand there are tools like SimaPro and GaBi for comprehensive life cycle assessments of any product. Built environment projects can be modelled in these programs in as much detail as required, but not many predefined construction elements are available.
The Footprint LCA Software or eTool on the other hand are targeted towards buildings and can be extended to precincts or infrastructure projects. Their databases are streamlined for these applications and the material selection is structured by construction elements for easy navigation.
The third category, the integration of embodied carbon in Building Information Models (BIM), goes one step further and ties the carbon calculations directly into the design process. Tally is an example.
The fourth category of tools are Excel-based infrastructure carbon calculators like the Carbon Estimate and Reporting Tool from Transport for NSW and the Infrastructure Sustainability Materials Calculator from the Infrastructure Sustainability Council of Australia.
So what would the features of an ideal tool be? This depends on the specific target of analysis. The level of detail needed for carbon calculations should guide the depth of the software model. For a quick overview, high-level estimates with predefined default values are sufficient. In contrast, a detailed comparison of design variations require accurate figures. Here, the underlying database plays an important part. Australia-specific carbon data are not as abundant as data for the US or Europe, but country-specific data are crucial for precise results. Furthermore, few tools allow for a comparison between embodied and operational carbon emissions or for complete life cycle assessments including additional environmental impacts such as resource use, air pollution or toxicity.
Considering that the software-based assessment of embodied carbon emissions is still an emerging field, it is not surprising that there is potential for optimisation. Two aspects stand out.
First, more tools should account for both embodied and operational emissions at the same time. This would facilitate designing buildings and precincts in the sweet spot between energy efficiency – by integrating high-grade insulation and using low carbon materials.
Second, the underlying data sources and algorithms should be fully transparent. In most cases, the databases included in these tools are based on a variety of sources, have been calculated with different methods or come with a varying degree of quality and description. Data might be independently reviewed by third parties or might just be provided by one single company without further review. Obviously, the more transparency there is with respect to the underlying information, the more value the respective tool will provide. The previously mentioned scoping study revealed that these aspects are also major concerns of construction industry professionals.
The current research project Integrated Carbon Metrics (ICM) from the CRC for Low Carbon Living focuses on embodied carbon emissions in the built environment on several levels. Most prominently, Australia-specific data for embodied carbon emissions of built-environment products and services are being developed as well as tools that quantify embodied and operational carbon emissions.
One focal scope is the precinct level to enable planners to use the information in Precinct Information Models (PIM) tying the carbon calculations directly into the design process of precinct planning, thus allowing to better explore and assess low carbon options throughout the design stage.
Additionally, information will be provided on where the emissions related to the built environment originate. ICM data and tools will be delivered under an open source licence for transparency, flexibility and availability. Scenario models will give an insight into how close to a low carbon society we can get with the planning of low carbon precincts.
Including embodied carbon emissions in project assessments is a holistic concept and it may need some getting used to before stakeholders consistently think along these lines, but they will help to finally bring Australia’s built environment into the 21st century.
Judith Schinabeck, Thomas Wiedmann and Sven Lundie are part of the Sustainability Assessment Program in the School of Civil and Environmental Engineering at UNSW.