Critical Evaluation of LEED (Leadership on Energy and Environmental Design) - Using Life Cycle Assessment Year 2
This project focuses on the application of the Life-Cycle-Assessment (LCA) methodology to enhance metrics and tools for assessing buildings' environmental impacts. These objectives will be accomplished by using the previously completed life cycle inventory of a classroom/office building on the University of Michigan campus (Sam Wyly Hall) to explore the environmental implications of LEED credit points. The project is organized in three phases over a three-year period.
Utilize LCA methods to determine energy and solid waste impacts of certain LEED credits, and examine implications of impacts for LEED's point distribution within the following credit sections:
· Material credits
· Energy credits
a) Assess environmental impacts of base case building (Wyly Hall)
b) Research energy and solid waste impacts from changes neccesary to accomplish credit requirements
c) Run alternative scenarios and establish energy and solid waste impacts from credit decisions
d) Compare point distribution in LEED to LCA-based distribution of environmental impacts
e) Compare environmental impacts between different credit sections i.e. materials to energy
Previous Work Goals
a) Test the use of BEES 2.0 b on state-of-the-art commercial building, and combine BEES' per-unit outputs with the building materials inventory in order to generate an overall environmental profile of the building's materials.
b) Develop a total-life-cycle model of Wyly Hall using BEES 2.0 b in combination with thermal modeling software, while also incorporating the end-of-life phase. For a more comprehensive LCA of Wyly Hall, we will identify materials and environmental impacts not included in BEES 2.0 b, both, through a detailed material inventory, and the use of non-BEES LCA resources . By comparing these results we will be able to determine the fraction of total impacts covered by the current BEES version.
c) Based on the results in b) recommend improvements of the current BEES version.
a) The total coverage for available BEES modules represented only 18% of the life-cycle material inputs for Sam Wyly Hall. Impact coverage for energy and the environment were roughly proportional to the material coverage.
b) The coverage of materials which are generically present in BEES was 50%, which suggested that in order to provide a widely applicable solution for the building industry, the BEES database needs both a greater range of material modules and a wider choice of modules within a specific category.
c) A total life-cycle inventory of Sam Wyly Hall was completed. This LCI covered 99.8% of the calculated building mass. Use phase burdens were calculated using thermal modeling. Life cycle Embodied energy for materials only accounted for about 5% of the total life cycle energy. Building operations accounted for about 95% of the life cycle energy.
d) Environmental impacts (GWP, AP, ODP, waste) for this LCI were completed using current impact literature. Issues involved with the methods for calculating resource depletion were explored, with a resulting recommendation that resource depletion be reconsidered in future BEES versions.
Future Research Directions
· Development of embodied energy credit format for LEED material selection utilizing BEES database
· Examination of material choices not addressed within LEED for example:
- Life cycle burdens of materials with high replacement rate (e.g., plastic carpet)
- Use of materials and products with producer take-back option (e.g., leasing flooring)
· Utilize LCA methods to determine environmental impacts of the LEED water efficiency and sustainable sites credits