Embodied energy in buildings : wood versus concrete - reply to Börjesson and Gustavsson

We analyse the wood and concrete designs of the Wälludden building described by Börjesson et al. (Energy Policy 28 (2000) 575) in terms of their embodied energy, employing an environmentally extended input–output framework in a tiered hybrid life-cycle assessment, and in a structural path analysis. We illustrate the complexity of the inter-industry supply chains underlying the upstream energy requirements for the building options, and demonstrate that higher-order inputs are difficult to capture in a conventional process analysis. Our calculations show that Börjesson and Gustavsson's estimates of energy requirements and greenhouse gas emissions are underestimated by a factor of about 2, and that corresponding greenhouse gas balances are positive at about 30 t C-eq. Nevertheless, Börjesson and Gustavsson's general result—the concrete-framed building causing higher emissions—still holds.