Carbon assessment of building shell options for eco self-build community housing through the integration of building energy modelling and life cycle analysis tools

Abstract

To achieve the UK's net-zero carbon transition by 2050, new homes need to be designed to high energy efficiency standards and minimise life cycle carbon emissions. This study develops a method that integrates building energy modelling (BEM) and life cycle assessment (LCA) tools, IES Virtual Environment (IES VE) and One Click LCA, to conduct a life cycle assessment of the operational and embodied carbon impacts of a typical terraced building shell in an eco self-build community housing (ESBC) project, using Water Lilies as a case study. It evaluates and compares the 60-year life cycle carbon impacts of six design options that apply different insulation materials to the case study building shell. The results are based on grid-connected Future Energy Scenarios (FES) that have different carbon intensities predicted over time and the microgrid-connected Water Lilies Community Energy (WLCE) scenario that is operationally net-zero carbon. Depending on the FES, embodied carbon accounted between 59 and 80% of total emissions compared to 20–41% from operational carbon across design options. The results show that operational carbon is highly sensitive to the percentage of renewables in the energy mix of the grid, which is difficult to predict, and can significantly influence the design choice. As such, future researchers should account for predicted changes to the carbon intensity of the grid by applying a similar method to that proposed. Overall, the integration of IES VE and One Click LCA provided a more streamlined life cycle assessment to help inform early design decisions by enabling energy consumption simulation in BEM to assess operational carbon emissions and the automated transfer of building materials from the BEM model to the LCA tool to assess embodied carbon emissions. The limitations included the unavailability of material-specific data in early design stage plans, the inability to automatically transfer the timber frame structure from IES VE to One Click LCA, and the uncertainty of future energy trends.