Concrete vs. wood in buildings – An energy system approach

Substitution between energy and CO2 intensive materials is a potentially important climate mitigation strategy. We compare buildings with concrete frames and wooden frames concerning their life-time carbon dioxide emissions as well as their total material, energy and carbon dioxide costs. By using consistent energy systems scenarios meeting stringent targets for atmospheric CO2 concentrations we investigate the impact of higher energy and carbon dioxide prices as well as of the availability of carbon capture and storage (CCS) technologies. We find that wooden frames cause lower carbon dioxide emissions given the prevailing energy system, but concrete frames obtain about the same emissions as the wood frame in a system where CCS is not used for wood incineration in the demolishing phase. The net present costs for the different buildings are also affected by the future energy supply system, even though the impact is small, especially compared to the total construction cost. We conclude that it is unclear whether wood framed buildings will be a cost-effective carbon mitigation option and that further analyses of costs should be performed before prescriptive materials policies are enforced in the buildings sector.