Our energy supply is decarbonising: fuel sources are changing – the UK’s electricity supply is now only 3% derived from coal – and should be zero by October 2024. In the 3rd quarter of 2019 40% of our energy was derived from renewable sources – wind, biomass, and solar. Transmission and distribution losses are still between 5-10% from the grid as a result of the large distances from giant power stations to the end user, but this will reduce as the grid is gradually becoming “smarter” to allow for more (local) microgeneration and storage.
There are some things to be optimistic about, but there is still a huge amount of CO2 going into our atmosphere as a result of the construction process – the embodied energy of buildings. This embodied energy is simply the amount of energy used in order to make and transport the materials and components that go into our buildings. In the course of time embodied energy will matter less as the energy we use to make those materials becomes cleaner. But in the meantime there is a renewed focus on embodied energy: The construction industry consumes around 400m tonnes of materials in a year and around 10% of UK total CO2 emissions. A residential building will use approximately 50% of its whole life carbon output (embodied energy + energy in use over 60 years) by the time it reaches practical completion, so reducing embodied energy becomes relatively more and more important as we get better at reducing the amount of energy in use in our buildings.
There is a renewed focus in particular on the reduction of Embodied Carbon in buildings. There are a few notable schemes and tools (EG FCB Studios’ FCBS free to download Carbon calculator) that have emerged recently with the aim of helping the industry to understand, quantify and do something about reducing the amount of carbon being used in construction
The RIBA for example has published a set of targets ( 2030 Climate Challenge) and the LETI ( London Energy Transformation initiative) sets targets for the next few years. The RIBA 2030 target for embodied energy is to reduce embodied Carbon from 1000 kgCO2e/m2 to 300 kg CO2/m2. The LETI targets are more ambitious and typology specific, identifying a 40% embodied carbon reduction target by 2020, and a 65% reduction by 2030.
There is no doubt that this will be challenging, and unfortunately at the moment, this is still very much a niche area of interest for the industry, with only a limited number of very dedicated professionals and academics really getting to grips with the whole challenge. In our view, the targets will not be met across the sector unless or until the targets become mandatory and will then be applied to the whole of the industry. In other words, too much of our industry sees the building regulations requirements as a maximum target, not a minimum, and as things stand there is no target or standard in the building regulations for limiting the amount of embodied carbon in a building.
At Designscape we have started to write in a Carbon Emissions target into our appointment documents, which includes a target for embodied energy so that Clients have to opt out rather than opt in. We see it as applying gentle pressure, and as part of our commitment to the Architects Declare movement. If we talk about it at the outset, and design around an agreed target from the outset, then it is much less likely or possible for a client to later decide that they want to cut down on those commitments. Reducing energy in use is a much easier sell than reducing embodied energy because everyone likes reducing energy bills, but reducing embodied carbon is of no direct economic benefit to an individual client. This is why it needs to be mandatory.
It isn’t difficult though: The tools are there, already on our desktops, to be able to measure the amount of carbon in a design: We have had the tools for a while without even realising it. Various commonly used CAD packages such as Revit and Archicad – Designscape uses Archicad as our main production tool – already have the ability to schedule the materials in a building, and they have built in a common materials embodied carbon database (Inventory of Carbon and Energy / University of Bath Carbon dataset published by the ICE ) which allows a common standard methodology to emerge. This dataset seems to be now the UK’s standard point of reference. This data set will vary in different countries to reflect the different ways and means by which materials are manufactured in different places, and of course, it will require updating regularly to reflect the changes that are occurring in our energy supply networks. But one of the best things about the use of a database built into the CAD model is that the designer can test the impact of various specification choices as the design emerges.
This is much more useful than some other standalone calculation tools that exist, which are much more limited in terms of the type of structures that can be evaluated EG some cannot account for an atrium or balconies. These would suggest that you may as a designer have a choice about whether or not to add another floor or a basement – which of course you don’t. The amount of development that is required is determined by other economic drivers, and usually demands maximizing the development potential of a site. But I suppose there is a place at the feasibility stage for looking at alternative forms and determining the relevant carbon content, in particular where there is an option for retaining an existing structure. These considerations will also affect cost and therefore viability, which may sometimes turn out to be better if an existing structure is reused.
I have outlined above two reasons to make a reduction in embodied energy a mandatory requirement in the building regulations: Unless it is mandatory it will remain a niche area of interest and the vast majority of the construction sector will simply ignore it. And there is no financial benefit in embodied carbon reductions to individual clients.
But we have the knowledge and the tools, so all we really need in order to turbo charge the take up of embodied CO2 reduction across the whole industry is a simple compliance target, calculated using a common methodology, and it needs to be mandatory. A new Part L3 if you like. It happens for all sorts of other parts of our design process, so why not for embodied Carbon? We need something very similar to a SAP or SBEM calculation – used to calculate and demonstrate compliance for energy in use. Until we have that, the majority of construction projects in the UK will simply comply with the building regulations and go no further…
The Government is currently consulting on proposed changes to the building regulations – The Future Homes Standard, which won’t even come into play until 2025, and, as yet, there is no mention of any requirement to assess the embodied carbon or to comply with any limits. It is still all about energy in use, although that is now likely to be only 50% of its Whole Life Carbon content…
The time has come for the Government to grasp the nettle and make it mandatory as there are no longer any valid excuses for not doing so. The designers have the tools, and there are established targets, but at the moment it remains unofficial guidance produced by the committed people in our industry and it will remain a niche activity that will never make the difference that is needed – until we live in a zero-carbon energy supply world.
