We are excited to see the release today of the Embodied Carbon Calculator we have developed with the New Zealand Green Building Council (NZGBC).
Measuring and reducing carbon emissions in the construction industry
Our 2018 report Hotspot or not? The carbon footprint of NZ's built environment revealed that buildings and infrastructure contribute up to 20% of New Zealand’s carbon emissions. Embodied carbon – stemming from the materials and products a building is made from – accounts for around half of these emissions. Spurred on by this data the industry has been asking for a way to measure and reduce its footprint.
Developed with industry, the newly released Embodied Carbon Calculator, calculator guide and methodology provide a robust and consistent approach to calculate upfront carbon and whole-of-life embodied carbon.
'We hope that the calculator and supporting documentation will help provide a consistent platform to measure embodied carbon while the New Zealand government finalises the Building for Climate Change programme,' our Technical Director Jeff Vickers says. 'We also worked closely with the Green Building Council of Australia and NABERS in Australia to provide consistency on both sides of the Tasman.'
Promoting a more consistent approach
Until now the industry lacked a consistent approach. Builders, architects and specifiers who went to five different consultants and asked them to calculate the embodied carbon in their building would likely have received five different answers.
We’ve built consistency in several ways. We defined:
- which elements of the building are included and which are excluded. E.g. do we include the carpets? What about the doorknobs?
- how to model the elements of a building’s life cycle for which there is little data. This is particularly for building services (mechanical, electrical, plumbing – like heating/cooling, lighting, power, pipes).
- how to handle biogenic carbon stored in bio-based materials.
- how to handle credits for recycling and reuse at the end of the building’s life.
- a procedure for choosing data.
- standard assumptions for rates of construction and demolition waste and replacement cycles.
- We also developed a standard database that covers most common materials and products used in non-residential buildings. And matched our work as much as possible with frameworks that are still under development. These include MBIE’s Building for Climate Change (BfCC) programme in New Zealand and the NABERS Embodied Emissions programme in Australia.
Making the calculator easy to use
Most of all, we tried to make the calculator easy to use. We know project teams are short on time, so we’ve focused on information they are likely to already have available or can get their hands on without too much additional work.
Getting the industry ready for new regulations
We’re aiming to support the New Zealand building and construction industry to get ready for coming developments like Building for Climate Change. Reporting on embodied carbon for new buildings will become mandatory in 2025. While BfCC is still being developed, the Embodied Carbon Calculator provides a method and tool for right now.
Two versions of the Embodied Carbon Calculator are now published on the NZGBC website. One is for project teams. The other invites tool developers to use the data and methodology to apply a common approach to measuring embodied carbon.
Read the NZGBC press release here.
10 May 2023