Economic impact assessment of carbon pricing of embodied greenhouse gas emissions for commercial office construction

摘要

A life cycle study was undertaken to assess the economic impact arising frominternalised embodied greenhouse gas emissions (GGE) costs for acommercial office building. A limited range of design and materials re-cyclingstrategies were investigated for their abatement potential. GGE quantitieswere determined by a hybrid process analysis where input-output data wassupplemented with national average data to increase completeness wherebyall upstream emissions arising from material inputs to the point of extraction,as well as non-material inputs (e.g. goods and services) into the design andconstruction process are accounted for.The hypothesis proposed abatement potential of 30%, as measured againstthe Benchmark Design (BM) would be economically viable in absence of thebenefit of early-action credits. The hypothesis was disproved with 15%abatement shown at zero additional capital cost. A Stretch Technology (ST)scenario was investigated which showed 32% abatement potential howeverthe associated marginal capital cost could not be determined. The GGEintensity per meter square of Net Lettable Area (m2 NLA) for the case studybuilding was found to be 5,258 kg CO2-e. The theoretical value of abatementcredits was determined at $12 to $1,031 / m2 NLA (depending on price) and isshown to present a reasonable economic and market transformationopportunity at medium range values.The results demonstrate that the cost-push inflation risk posed to commercialoffice construction is large where the price of embodied GGE is internalised inthe economic system. Gross Construction Cost (GCC) increase per squaremeter is shown to be between 1.5% and 61% (with associated negative IRRimpacts between -0.1 to -7%) depending on the GGE price level. Anunsustainable cost impact is demonstrated at GGE prices greater thanAUD$50 per tonne of carbon dioxide equivalent (AUD$50/ tonne CO2-e).Internalised GGE studies have been largely limited to the operational costimpact arising from GGE of direct end-use rather than from the perspective oftotal embodied final demand. The results demonstrate the critical nature ofembodied abatement strategies for commercial buildings if the internationallyaccepted 60% global GGE abatement is to be achieved within the relevanttimeframe. An average kg CO2-e intensity per dollar of GCC is proposed forthe three building models that may be applied to general scenario planning.The scale of economic benefit available for embodied credits is significant andthe determination of viable credit mechanisms worthy of further research.