How we can save carbon now by measuring it right
The key to reducing the overall carbon footprint of our buildings is long term value when it comes to construction materials.
Getting to net zero will require a lot of effort, but it also requires good data and measurement. The built environment is a good example, with long-lived structures and complex relationships between the materials and components that make up a building, and therefore the carbon emissions associated with it over its lifetime.
It is essential to recognise that there is a relationship between the way something is constructed (the fabric of the building) and the energy it uses.
When we assess carbon emissions from buildings and infrastructure, we should avoid a distorted picture that focusses on some sources of emissions, but not others. Currently the Building Regulations do not cover embodied carbon at all, and calls to include them are sensible. New buildings should be designed to be energy efficient to reduce fuel consumption and to make efficient use of materials in their construction.
There is currently a lively debate, with lot of focus on the emissions from the materials, construction, and demolition. This is important, but it mustn’t lead us to forget about operational emissions – the emissions associated with a building’s use over the course of its lifetime – which are the majority of emissions in most buildings. The sensible answer to the question ‘what about the carbon from building materials’ is whole life cycle analysis.
This is already happening in some places, including London. The London Plan recognises the importance of looking at a building’s carbon footprint holistically, which is why it requires whole life carbon emissions assessments for major projects.
Provided it is done right, incorporating genuine whole life assessments into national planning policy and the Building Regulations would not only help reduce carbon emissions today, but also provide a ‘carbon resilient’ built environment in which the upcoming emissions – from when the building is in use, and at the end of its life – are minimised. It would create an incentive to use the lowest carbon concrete for the task, while not sacrificing operational efficiency over a structure’s lifetime for smaller but more immediate savings in embodied carbon emissions.
It would also encourage architects, engineers and designers to get the most out of the buildings they are producing, for instance by designing buildings to last a very long time, and by making the most of thermal mass – an attribute that ‘flattens out’ the building’s temperature amidst changing outdoor temperatures, keeping buildings naturally cooler during summer heat and warmer during cold winter nights. This reduces the amount of energy needed for heating or air conditioning, compared to an equivalent timber or steel structure.
Good low carbon buildings should be built to last, and concrete and masonry have a proven track record for low maintenance, durability and resilience. The longer a material is in use, the lower its overall carbon footprint – effectively providing more ‘value’ for the carbon originally expended in the materials.
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