LCA Review of LEED

“Evaluation of LEED™ Using Life Cycle Assessment Methods” by Chris W. Scheuer and Gregory A. Keoleian, Center for Sustainable Systems, University of Michigan. Report prepared for Barbara Lippiatt, Building and Fire Research Laboratory, National Institute of Standards and Technology. Document #NIST GCR 02-836, 157 pages, 1.8 MB file available for download from www.bfrl.nist.gov/oae/software/bees/buzz.html.

If the LEED™ Rating System were perfect, each point achieved by a building would reflect the same amount of improvement in environmental performance. Researchers Scheuer and Keoleian set out to see how closely LEED approaches this ideal in the case of a particular building on the University of Michigan Campus: Sam Wyly Hall.

Reflecting the daunting scope of this effort—or the limited capabilities of currently available lifecycle analysis (LCA) tools—the authors were forced to significantly limit the scope of their study. Rather than analyzing the whole of LEED, the researchers studied six credits: three from the Energy & Atmosphere section (Optimize Energy Performance, Renewable Power, and Green Power), and three from the Materials & Resources section (Construction Waste Management, Recycled Materials, and Local/Regional Materials). In addition, they looked only at the impacts of the credits on energy use and solid waste generation, rather than on a full spectrum of environmental-impact categories. In spite of these severe constraints, Scheuer and Keoleian developed some intriguing findings and identified some important weaknesses in LEED.

While some of their recommendations are debatable, others address clear shortcomings. For example, they note that because the second point for Local/Regional Materials is calculated based on the amount of material used to get the first point, it is possible that by increasing the amount for the first point, one can lose the second. They also make the interesting discovery that the energy efficiency points contribute more to reducing solid waste generation (in addition to energy use reductions) than do the materials points. As LEED evolves, this sort of analysis will be invaluable in improving its consistency with real-world environmental impacts.

– NM