The Role of Embodied Carbon Databases in the Accuracy of Life Cycle Assessment (LCA) Calculations for the Embodied Carbon of Buildings

Studies conducted by major national and international scientific bodies have indisputably concluded that the increase in anthropogenic greenhouse gas emissions (GHG) since the mid-20th century has led to irreversible changes in the climate. Data has shown that the contribution of the building sector accounts for 39% of these emissions. Reducing GHG emissions associated with the construction phase of buildings, or embodied carbon (EC), will prevent GHG emissions from entering the atmosphere earlier, reducing the negative impacts. However, to achieve any meaningful reduction, there is a need for consistency and accuracy in the calculations. The accuracy of these calculations is primarily tied to the accuracy of embodied carbon factors (ECF) used in the calculations, values determining the environmental impact of a product or procedure per unit weight. The emissions of any product can be calculated by performing a Life Cycle Assessment (LCA). While the requirements for carrying out an LCA have been standardised in ISO14044, the lack of a definitive national ECF database in the UK means that EC calculations can vary drastically based on the chosen database. An LCA has been carried out on a standard Lidl supermarket design within the A1–A3 boundary. For the calculation, the ECFs were sourced from two different databases, using the GHG conversion factor data published in 2020 by the UK Department of Energy & Climate Change and data published in 2019 by the Inventory of Carbon and Energy (ICE). The latter is currently accepted as the most consistent database for carbon factors in the UK. This study showed that using a more detailed database compared to using a more general database could result in a 35.2% reduction of embodied carbon, while using more detailed data from a single database can reduce it by a further 5.5%. It is necessary to establish the most accurate baseline for embodied carbon so that any carbon reduction attempts can be as effective as possible