Carbon value engineering: A framework for integrating embodied carbon and cost reduction strategies in building design

Abstract

Value Engineering (VE) is a process where building materials, systems or design strategies are substituted to reduce capital costs without negatively impacting functionality. This research examines how Value Engineering can be adapted to also integrate the reduction of embodied carbon. A Carbon Value Engineering (CO2VE) framework is proposed to determine both capital cost and embodied carbon. The framework uses Pareto Principles to identify the primary contributors to these metrics, proposes alternative design strategies and uses Marginal Abatement Cost Curves (MACC) to visualise direct and indirect impacts of the changes. The framework is tested on an 18-storey building in Sydney. Results show that embodied carbon makes up 27–58% of the building's total lifecycle carbon emissions, depending on the future energy mix. The most significant contributor to embodied carbon and capital cost is the structural system. Alternative structural systems are evaluated with a post-tensioned concrete structure demonstrating an 8% reduction in embodied carbon and a 10% capital cost saving. A whole timber structure reduces embodied carbon by 13%–26% and cost by 5%. Embodied carbon savings are found to be comparable to conventional strategies to reduce operating carbon emissions such as the use of a high-performance building façade over the building's life.