Evaluating Strategies to Mitigate the GHG Emissions at Construction Sites Against Contractor Costs

The construction phase of buildings contributes significantly to greenhouse gas (GHG) emissions, yet mitigation strategies within the contractor’s scope—particularly those affecting transport, on-site energy use, and waste—remain underexplored in life cycle assessments (LCAs). This study develops a modelling framework to evaluate 20 mitigation strategies targeting modules A4 and A5 of the LCA, using a generalised business-as-usual (BAU) scenario derived from 15 representative archetypes based on 279 built projects and weighted by national construction statistics. Monte Carlo simulations are applied to capture variability in material composition and component distribution, and marginal abatement cost analysis is used to assess cost-effectiveness. The results show that transport-related strategies offer the highest mitigation potential under Danish conditions with minimal or negative costs, while waste strategies provide moderate reductions and often result in net savings. Energy strategies, though impactful in percentage terms, tend to have lower absolute reductions and higher costs. The applicability of strategies varies across building sizes, with economies of scale influencing feasibility. The modelling framework offers a structured basis for comparing mitigation actions by climate benefit and cost-efficiency, supporting strategic planning for low-carbon construction, while recognising that practical implementation depends on project-specific and organisational factors.