Science-Based Guidance for Environmental and Economic Sustainability

Industry stakeholders need compelling metrics, tools, data, and case studies supporting major investments in sustainable technologies. Proponents of green building, for example, widely claim that these buildings are cost-effective, but often these claims are based on incomplete, anecdotal evidence that is difficult to reproduce and defend. The claims suffer from two main weaknesses: (1) technologies upon which claims are based are not necessarily ?green? in a science-based, life-cycle assessment (LCA) sense and (2) their measures of cost-effectiveness often are not based on standard methods for measuring economic worth. Yet industry demands compelling metrics to justify sustainable technology investments. The problem is hard to solve because, until now, neither methods nor robust data supporting defensible business cases were available. The National Institute of Standards and Technology (NIST) is beginning to address these needs by developing rigorous metrics and tools for scientifically assessing the life-cycle economic and environmental performance of complex industrial systems such as buildings, automobiles, and farm equipment. Economic performance is measured using standard life-cycle costing methods. Environmental performance is measured using LCA methods that assess the ?carbon footprint? of industrial systems as well as 11 other sustainability metrics including fossil fuel depletion, smog, water use, habitat alteration, indoor air quality, and human health. Carbon-efficiency ratios and other eco-efficiency metrics are established to yield science-based measures of the relative worth, or ?business case,? for sustainable technologies. The approach is illustrated through case studies of energy efficiency investments in commercial buildings.