New embodied carbon calculator available

The New Zealand Green Building Council (NZGBC) and sustainability consultancy firm thinkstep-anz aim to make it easier for builders to calculate the amount of embodied carbon emissions in buildings

Embodied carbon is the carbon dioxide emissions a building is responsible for over the course of its lifetime. This takes into account the emissions produced during the construction process and during the manufacture of materials, however, it does not take into account the energy used to run the building (called embodied energy).

Before embodied carbon can be reduced, it must be calculated and understood. The NZGBC and thinkstep-anz want to make it easier for builders to work out the amount of emissions in each building.

Better calculated, better understood

To accomplish their goal, a new calculator has been unveiled as well as guidance on how to use it so the building and construction get a more consistent approach to figuring out the sector’s carbon footprint. According to the NZGBC, the assets will “pave the way for the building and construction industry to reduce emissions from building materials and supplies”.

While there are several carbon calculators available to builders, making sure they all deliver consistent results is important – said NZGBC Chief Executive Andrew Eagles.

“Several of our members and other industry bodies have developed embodied carbon calculators. This is a fantastic starting point, [but] now we need to ensure they align. If we’re going to tackle our emissions, it’s essential our sector has a consistent and comparable approach to measuring emissions.”

A 2018 report by thinkstep-anz reported that buildings and infrastructure account for 20% of New Zealand’s carbon emissions, and embodied carbon accounts for half of it.

Eagles said that accurate measurement of embodied carbon is an important first step to reducing it.

“Our industry has become increasingly aware of the pollution caused by the manufacture and production of our materials and products. Awareness is all well and good, but we need to actually start measuring the carbon footprint of our projects robustly so we can reduce it as much as possible.”

Sector consultation

To develop a more accurate calculation of embodied carbon, the NZGBC and thinkstep-anz worked with a sector reference group from across the construction industry.

“Through these discussions we’ve identified a need to develop an industry-wide approach to support the definition, scope and calculation of embodied carbon. We hope that the calculator and supporting documentation will help provide a consistent platform to measure embodied carbon while the Government finalises the Building for Climate Change programme,” said thinkstep-anz’s Technical Director Jeff Vickers.

The Green Building Council has also updated its Green Star certification scheme for commercial buildings and added a requirement to reduce embodied carbon by at least 10% compared to a standard reference building.