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Objective:
Develop metrics, tools, and data supporting sustainable building design decisions.
Problem:
BFRL stakeholders need compelling metrics, tools, data, and case studies supporting major investments in sustainable building technologies. Proponents of green building widely claim these buildings to be cost-effective, but these claims are based on biased, anecdotal evidence that is difficult to reproduce, much less defend. The claims suffer from two major weaknesses: First, the green buildings upon which these claims are based are not necessarily “green” in a science-based, life-cycle assessment (LCA) sense. Second, their measures of cost-effectiveness often are not based on standard methods for measuring economic worth. The problem is hard to solve because, until now, neither methods nor robust data supporting defensible business cases were available. Yet industry and society care: the U.S. Green Building Council needs compelling metrics to help introduce more science in its Leadership in Energy and Environmental Design (LEED) rating system. Federal executives need them to help prioritize sustainable building research. The many “national assessments” of construction sustainability underway by BFRL stakeholders need them to identify which industry practices are most in need of sustainability improvements. The problem is hard because, on the one hand, industry and academic stakeholders demand transparent, peer-reviewed methods and data, but on the other hand, building owners and designers demand easy answers to complicated questions that are made available through simple software tools and illustrated with detailed case studies.
Approach:
BFRL proposes to begin addressing these stakeholder needs by expanding the scope of BEES beyond building products to major systems and, ultimately, entire buildings. BEES’ scope will be expanded by developing a hybrid of “top down” and “bottom up” LCA approaches.
The top down LCA approach is based on economic input-output tables produced by the U.S. Department of Commerce, Bureau of Economic Analysis. These tables measure, in dollar terms, the ripple effects throughout the U.S. economy based on a dollar amount of economic activity in any single sector (e.g., “new office, commercial, and industrial buildings construction,” “refrigeration and heating equipment”). The level of resolution of U.S. input-output statistics is the best in the world, encompassing a great many of the production technology mixes in widespread use today.
Moreover, several academics recently have developed environmental data compatible with U.S. economic input-output tables. This work is recognized worldwide as advancing the state-of-the-art of LCA: It quantifies the environmental flows from an industry’s supply chain based on its current technology mix, enabling modeling of industrial processes—and their associated environmental inputs and outputs—involved in raw materials acquisition, manufacturing, transportation, installation, use, and waste management.
The bottom up LCA approach implemented in BEES enables “what if” analyses of alternative technology mixes. By considering how alternative industrial processes change the flow of raw material, water, and energy inputs from, and releases to, the environment, the life-cycle environmental impacts of these changes can be assessed.
In FY08, BFRL will work with industry to develop and illustrate a hybrid top down/bottom up LCA approach. Metric development will focus on combining the strengths of each and addressing their weaknesses: the top down approach has broader coverage, but does not address technology changes like the bottom up approach does. A metric will be developed permitting technology mix changes in the top down approach informed by the bottom up approach.
BFRL will address data issues by working with a top down LCA expert to address a number of data incompatibilities between BEES data and environmental input-output data, such as in specification and measurement units of lengthy environmental flow lists (BEES evaluates more than 500 environmental inputs and outputs, including raw material and energy inputs, air emissions, water effluents, and solid waste). BFRL will collaboratively develop a mapping framework to directly connect, and convert if necessary, input-output environmental flows to their equivalent BEES flows. Without such a mapping framework, the hybrid BEES approach cannot succeed.
BFRL will work with industry to specify major systems, based on current technologies, in one commercial and one industrial building. BFRL will seek input from groups such as the Council on Tall Buildings and Urban Habitat and the Construction Industry Institute in this endeavor. It will then develop a case study that applies its hybrid LCA approach and data to the two case study buildings.
BFRL will begin accommodating BEES’ expanded scope in its web-based BEES tool by building capacity for building system and entire building sustainability analyses. The expanded BEES tool, once complete, will support BFRL stakeholder needs for compelling metrics and data supporting major investments in sustainable building technologies.
The FY08 deliverable is a published conference presentation documenting the hybrid BEES approach and illustrating it with the two realistic cases studies. The approach is innovative because it is a novel, hybrid approach combining the strengths of two LCA approaches.
In FY09, BFRL will incorporate stakeholder feedback in finalizing its hybrid BEES approach, refining its data, and publishing web-based decision making software automating the technique. Similar to the existing BEES tool, it will be developed for a non-technical audience assumed not to have a deep understanding of LCA. By informing their deliberations with life-cycle, science-based thinking, along with a standard life-cycle cost metric in the monetary terms they are accustomed to using, BFRL stakeholders can better allocate scarce dollars to building technology investments having reduced long-term consequences on our environment.
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