Embodied Carbon Insights
Embodied Carbon
Embodied carbon is now a core part of building assessment. In this article, we’ve outlined the main ways it’s measured in Australia, how upfront carbon differs from full LCA, and how Green Star Buildings v1.1 approaches Credit 24.
Assessing Upfront Carbon: Reference Building vs Benchmark
There are two common ways to assess a building’s upfront embodied carbon. The first is a reference-building approach, where the proposed design is compared to an equivalent “reference” version of the building, and the outcome is expressed as an improvement (or otherwise) against that baseline. The second is a benchmark approach, where the building’s upfront embodied carbon intensity is calculated and then compared to an external benchmark or target to show how it performs relative to market expectations.
Embodied Carbon Boundaries: Upfront vs Full Life Cycle
Upfront embodied carbon covers the emissions that occur before the building is in use, primarily from producing materials and products, transporting them to site, and constructing/ installing them. A full Life Cycle Assessment (LCA) goes further by accounting for emissions across additional life stages, which can include maintenance and replacement during use, end-of-life processes, and, in some frameworks, benefits beyond the building’s boundary (such as reuse or recycling). In other words, upfront carbon is a subset of LCA results. Upfront carbon is often the most actionable during design and procurement (because it locks in early), while whole-of-life LCA is used to understand trade-offs across the building’s lifespan and to avoid “optimising” upfront impacts in a way that increases impacts later.
Green Star Buildings v1.1 Credit 24 – Upfront Carbon Reduction
Pathway A - Benchmark: For eligible building classes, show the project’s upfront carbon is at least 10% below the published benchmark.
Pathway B - Reference building: Compare the proposed design to a reference building and show at least 10% lower upfront carbon (using the calculator or a comparative LCA).
Pathway C - NABERS Embodied Carbon rating: Use NABERS Embodied Carbon as an alternative benchmark pathway.
What we’ve learnt
Benchmark pathways (Green Star Pathway A and NABERS) don’t require a project-defined “reference building”. Performance is assessed against an external benchmark, which reduces debate about baseline assumptions and improves comparability between projects.
An extra point is available in Green Star Buildings v1.1 Credit 10 (Impacts Disclosure) by disclosing a whole-of-building, whole-of-life LCA.
If a full LCA is being completed, it’s efficient to also use it for Credit 24 Pathway B by running a reference vs proposed comparison for A1–A5 in an LCA tool (eTool, One Click LCA, or an equivalent platform).
Hotspot analysis makes LCAs useful early. Tools like eTool can highlight the biggest contributors so teams can target the largest wins first.
LCAs support Scope 3 accounting. With consistent quantities and emission-factor evidence, project LCAs can be structured into an auditable approach for organisational climate/ESG reporting—Rewild supports organisations to implement this consistently and repeatably.
