Designing Net Zero Carbon Buildings
What is Net Zero Carbon?
Simply put, Net Zero Carbon means that a project’s life-cycle greenhouse gas emissions from all sources should total zero, or less. These sources include:
- Life-cycle impacts of operational energy and water
- Life-cycle impacts of construction, including materials extraction, manufacturing, transport to the site, installation and wastage, repair, replacement, refurbishment and end of life processing
- Benefits (avoided impacts from) energy exported from the project to other users
- Benefits (avoided impacts from) reuse of materials after the project is decommissioned
- Benefit from permanently sequestered carbon (if any)
Why does Net Zero Carbon matter?
Commercially speaking, net zero carbon matters because leading construction clients and cities ask for it. Even if you do not consider climate change to be important, you need to respond to market demands.
The World Green Building Council’s Advancing Net Zero Commitment has been signed by national governments, cities and leading long-term property investors and many other investors, who have yet to sign, are interested in applying some of the best practices to maintain their credentials as responsible organisations.
From a global perspective, Net Zero Carbon matters because construction is responsible for 39% of all global carbon emissions.
The impact of energy grid decarbonization
Operational energy has long been the dominant source of construction life-cycle carbon emissions. But sustainable energy policies have changed the game.
Energy grid decarbonization means that materials life-cycle impacts are the dominant source of life-cycle emissions for any building with a lifetime of 50 years or more.
The flip side to the welcome growth of low carbon energy is that it has made it harder to offset emissions by exporting energy. You need to export enough energy to offset your emissions before the grid to which you export has reached zero emissions.
Exporting zero-carbon energy to a zero-carbon grid won’t offset any emissions!
All of which contributes to making materials carbon even more critical.
7 design strategies to achieving Net Zero Carbon
Reduce emissions from your project as far as practicable by:
1. Reducing virgin materials demand.
2. Reducing fossil energy demand.
Incorporate circular economy principles by:
3. Repurposing existing buildings and materials.
4. Reducing the need for material replacements during building life-cycle by choosing longer-lasting products.
5. Designing for adaptability, deconstruction and reuse: making your own materials and buildings repurposable.
Read more on circular economy principle in construction
Restore climate balance to achieve net zero carbon by:
6. Replacing fossil energy elsewhere.
7. Sequestering (biogenic) carbon.
Some climate benefits also arise from the end-of-life use of materials and, in the case of cementitious materials, from their carbonization during and after the building’s lifetime.
Designing for Net Zero Carbon with One Click LCA
Carbon accounting practices for construction works are largely set by EN 15804 and ISO 21930, which are the globally applicable standards for the life-cycle assessment of construction works. One Click LCA is certified for compliance with both.
With One Click LCA, you can:
- Select from a substantial range of reused and recycled materials to use in your carbon footprinting / LCA.
- Model the preservation of existing building elements.
- Adjust material service life and wastage assumptions.
- Adjust end-of-life scenarios from the market standard practice e.g. to model product reuse (within boundaries of standards).
- Export energy from the building to offset other energy flows at a system level.
- Sequestrate biogenic carbon (for any products used for the project).
- Access a library of 100+ tree types to allow for accounting in-life carbon sequestration.
- Model carbonisation for cementitious materials.
How to design and model projects to achieve Net Zero Carbon
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