Embodied Carbon

Embodied Carbon is the total greenhouse gas (GHG) emissions (often simplified to ‘carbon’) generated to produce a building or home. It covers the emissions that arise from the energy and industrial processes used in the processing, manufacture and transportation of the materials, products and components required to construct, maintain and refurbish a building such as a house. It also includes deconstruction, disposal and end of life aspects. It does not include Operational Carbon (emissions that arise from the energy used to operate the house e.g. the heating, cooling etc).

The Embodied Carbon which relates to emissions from the material production and construction phases before the building has been completed is known as ‘upfront carbon’. These emissions have already been released into the atmosphere before the building is occupied.

Embodied Carbon emissions from construction and the service life of buildings (usually a 60-year life) are significant and can represent more than 50-70% of the lifetime emissions of a new building. The relative significance of Embodied Carbon is likely to increase as the UK grid is decarbonised and Operational Carbon emissions reduce. Embodied Carbon emissions are “locked in” when the building is built – they can never be reduced, and their impact will be felt for the life of the building. Embodied Carbon savings made during the design and construction stage are delivered now, not in the years to come. This contrasts with operational emission savings which are delivered over time in the future.

Embodied Carbon is usually expressed in units of CO2. This usually includes a number of greenhouse gases (GHGs) including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF6). Each GHG has a different warming effect on the earth’s atmosphere. In order to aggregate the total effect of all gases, each is converted into its equivalent CO2 warming effect (global warming potential – GWP) and all CO2- equivalents (CO2e) are then added.

The measurement of the environmental impact of a product at all stages of the life cycle is called Life Cycle Assessment (LCA). LCA can be used to measure theenvironmental impact of a construction product, component or building. Impact categories are recorded within an LCA, of which climate change is one. Therefore, when undertaking an LCA, Embodied Carbon will be calculated using the GWP from the emissions generated throughout a product, component or building lifecycle. Other impacts measured include acidification, eutrophication, toxicity, ozone depletion and resource depletion. Both LCAs and Embodied Carbon assessments should be carried out by following recognised standards.