Whole life carbon assessment: what is it and why does it matter?
Whole life carbon assessment is the latest way to assess a build's green credentials. Here's what you need to know
By now we all understand the importance of making buildings that require little energy to heat and light, but the latest thinking in green construction expands this idea to try to minimise carbon use throughout the whole life of a building.
Whole life carbon assessment (WLCA) encourages us to think holistically about a building and the environmental impact of every single aspect of every stage of its life, from where materials are sourced to how they are transported to site; from how long they last to whether they can be reused or recycled.
Operational vs embodied emissions
Operational emissions are the carbon emissions created when the building is in use. Embodied emissions are those generated by the building’s construction.
Whole life cycle carbon
WLCAs attempt to estimate these embodied emissions from:
- production: including raw material extraction, manufacturing, transportation
- construction: including transportation, assembly, installation
- end of life: including deconstruction, waste processing, disposal
- beyond asset life: including reuse, recycling, energy recovery
This LETI factsheet goes into more detail.
Why it matters
Although embodied carbon in buildings is currently responsible for 11% of global greenhouse gases (versus 28% from operational emissions), as the world population grows, global building stock is expected to double by 2050. So, embodied emissions are an increasingly important issue.
Low-carbon design
There are lots of ways to minimise the whole life carbon footprint, including:
- design a building that is smaller and uses less carbon intensive materials
- minimise waste throughout the build – of materials, packaging etc
- build to last
- design a building that can be refitted, repurposed or disassembled
- use recycled materials (but check what their carbon footprint is: recycled doesn’t necessarily mean low carbon)
Calculating embodied carbon
The calculations required to work out the embodied carbon in a project are complicated. If you have a head for figures and an interest, the Institution of Structural Engineers has a good factsheet on how embodied carbon is calculated. Generally, these are sums that are probably best left to the professionals.
The Royal Institute of Chartered Surveyors has just published the second edition of its Whole Life Carbon Assessment Standard, which is the standard that building professionals use to help them.
Planning factors
WLCA is becoming an increasingly influential way of assessing the built environment. It underpins the trend for retrofitting commercial buildings rather than demolishing and rebuilding. And WLCAs are starting to appear in planning requirements for large commercial developments, such as those in London. And we all know that what happens in commercial property often spreads to domestic building, and what happens in London often spreads to the rest of the country.
Inspiring low-carbon builds
These LETI embodied carbon case studies show examples of mainly commercial and public buildings, but they give you an idea of the kinds of issues that are considered in WLCAs.
If you’re just looking for inspiring low-carbon buildings designed by young architects who are grappling with these issues and coming up with creative solutions, take a look at the short list for the 2023 Architectural Review’s Emerging awards. All the architecture practices on the list take their environmental responsibilities incredibly seriously, and yet still manage to build fun, interesting and playful buildings, all with very low embodied carbon.
