Implementation of a design and regulatory framework for Building Energy Simulation (BES) and Life Cycle Assessment (LCA) co-simulation as a pathway to net zero

The COP28 conference concluded with all 195 nations committing to transition away from fossil fuels, marking what has been described as the “beginning of the end” of the fossil fuel era, with a shared goal of achieving net zero by 2050. Aligned with UK targets, this includes net zero greenhouse gas emissions by 2050 and a 68% reduction in carbon emissions by 2030. However, significant gaps remain in guidance on achieving these targets, with criticism that current frameworks focus too narrowly on operational emissions, prompting calls for mandatory whole life carbon assessments. To address this challenge, this research proposes a framework that integrates energy and life cycle assessment (LCA) co-simulation into existing building compliance processes. Recognising that manual implementation would present insurmountable barriers due to cost, time, and expertise requirements, the research centres on automation and digitisation as essential enablers. Specifically, it explores how Building Information Modelling (BIM)-based energy and LCA co-simulation can provide a practical pathway to net zero assessment without placing additional burdens on designers or regulators. The framework termed the Framework for Building Energy Simulation (BES) and LCA Co-simulation was developed and validated through a case study building representative of early design stages. Validation was structured across four elements: demonstrating design-stage applicability, demonstrating regulatory compliance functionality, validating efficiency and scalability, and examining how automation reduces barriers to adoption. Real but extreme operating scenarios were tested to capture the full potential impact of dynamic co-simulation on the design process, with comparisons drawn against fully specified models under current Part L compliance standards. The research concludes that digitisation, automation, and co-simulation are critical enabling technologies for decarbonising the built environment. The framework offers a feasible and scalable solution, providing regulators with tools to assess both construction and operational carbon impacts, while equipping designers with an automated process to embed carbon assessment into decision-making from early design stages ultimately supporting a pathway towards whole life carbon reduction and a more sustainable future.