Environmental Impacts of Multi-Storey Buildings Using Different ...

- 129 -• What is the ranking of the buildings in terms of environmental impacts?____________________________________________________________________Initial embodied energy Best (least embodied energy) TimberPlusof materialsTimber(From Table 6.6)ConcreteWorst (most embodied energy) Steel___________________________________________________________________________Initial embodied CO 2 -eq. Best (lowest GWP emissions) TimberPlusof materialsTimber(From Table 6.7)ConcreteWorst (highest GWP emissions) Steel_____________________________________________________________________Total primary energy use Best (least total energy used) TimberPlusof building over full lifecycleConcrete- landfill scenario Timber(From Table 6.6) Worst (most total energy used) Steel___________________________________________________________________________Total GWP emissions Best (least total GWP emissions) TimberPlusof building over full lifecycleTimber- landfill scenario Concrete(From Table 6.7) Worst (most total GWP emissions) Steel_____________________________________________________________________Total GWP emissions Best (least total GWP emissions) TimberPlusof building over full lifecycleTimber- reutilisation scenario Steel(From Table 6.11) Worst (most total GWP emissions) Concrete_____________________________________________________________________• How important is the choice of energy and GWP data-set coefficients on LCAresults?The importance of the choice of energy and GWP data-set coefficients is significant.This is because the embodied energy and GWP of the various building materials – two of themost important environmental impacts assessed by LCA - are calculated by multiplying thequantities of materials in each building by an appropriate embodied energy or GWPcoefficient.As noted earlier (Section 9.4.3), due to the lack of locally produced and specific data forbuilding materials, a number of previous studies in New Zealand have been based onEuropean industry and energy data sets. However, processes, manufacturing and energysources in NZ - with a significant proportion of renewable energy generation being fed intothe NZ energy mix and wood processors, in particular, utilising locally produced biomassenergy – are often very different to those found in Europe and, thus, coefficients can be verydifferent.The recent study “Life Cycle Assessment: Adopting and adapting overseas LCA data andmethodologies for building materials in New Zealand” (Nebel et al., 2009) has addressedsome of the issues and produced a limited data set for the major building materials in NZ (see