Life-Cycle Assessment as a Comparative Analysis Tool to Measure Brownfield Redevelopment Sustainability
Brecheisen, Thomas Andrew
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Life-cycle assessment (LCA) is a tool that can be used to characterize the performance of brownfield redevelopment activities in conformance with the sustainability paradigm, which involves the simultaneous accomplishment of social and economic goals while responsibly managing the environment to ensure that the Earth can continue to support human existence into the indefinite future. A brownfield can be defined as any abandoned or underutilized property where private development is complicated by concerns (real or perceived) about environmental liability and cleanup costs for contamination caused by the previous property owner(s). For this reason, many former industrial and commercial properties sit dormant for years before returning to productive use. Often times, the degree of contamination at brownfield sites does not pose serious threat to human health or the environment; thus, brownfields also represent economic and social threats by inhibiting redevelopment and stifling local economies. Increasing government incentives and funding sources are now available to facilitate the redevelopment of these brownfields, but after environmental cleanup and building construction (or rehabilitation) activities, the redeveloped site substantially alters the built environment and has significant environmental, economic and social impacts for the coming decades. Thus, there is a significant need for sustainability metrics that can be applied to real systems and used to guide management action for the post-occupancy operational life-cycle stage. This work inventories the life-cycle impacts associated with three separate brownfield redevelopment projects, which were evaluated on two critical indicators: cumulative energy demand (CED) and global warming potential (GWP). Brownfield redevelopment activities include the following life-cycle stages: 1) brownfield assessment and remediation, 2) new building construction or rehabilitation, and 3) post-occupancy operation, including both building and commuter transportation energy consumption. Two of the three sites are commercial office buildings and the third site is a neighborhood community center. The two office buildings are similar in terms of size and function, but differ with respect to construction (new construction vs. rehabilitation), LEED certification and use of on-site renewable energy. The neighborhood community center is newly constructed and LEED certified, but differs from the two office sites in terms of size and function. The LCAs for the three sites are performed using identical scope and boundaries. In order to account for the differences among the three redeveloped sites’ features, the CED and GWP impacts are normalized for each life-cycle stage and combined into a dimensionless single score based on a 75-year post-occupancy building lifespan. The LCAs identify the most significant components of each life-cycle stage and evaluate multiple normalization scenarios. Different fuel sources (coal, natural gas, nuclear) for electricity production, the benefits of on-site solar electricity, and the effect of public transportation systems on commuter transportation impacts are investigated while a comparison of predicted vs. actual building energy consumption is highlighted. This research culminates with normalized LCA sustainability metrics used to compare three different sites using common indices, representing each site’s performance with respect to energy consumption and the associated greenhouse gas emissions.
cumulative energy demand
global warming potential