Energy Efficiency, Sustainable Development and Natural Resources Conservation: Multicriteria Life-cycle Analysis of Daily-Used Materials with a Long-term Vision

This paper explores the role of energy use in sustainable development and the potential sources to increase energy efficiency during the whole life-cycle of any material and its production process. It is the first paper of a research project exploring a decision making model for a multidisciplinary problem in nature. It deals with Multicriteria decision making for plastic materials used in a day to day basis. We analyze plastic materials used to manufacture disposable polyethylene bags among other materials that can be used for their substitution. We are also interested in plastic (polyethylene Terephtalate or PET) bottles and its possible substitutes.
Sustainability considers the concept of exergy loss, Green House Gases emissions, real energy flows needed to the chain of manufacture processes, material balances in the productions chains and value added. These concepts are presented as a set of criteria to make decisions of alternative substitute materials.
The materials analyzed for possible substitutions comparison for the case bags are: Low Density Polyethylene (LDPE), LDPE with a pro degrading additive, unbleached Kraft paper, cotton and polypropylene (PP). For the case of polyethylene Terephtalate (PET) bottles, aluminum and glass are included for analysis as substitution materials, but more important yet the possibility of recycling is also considered.
A case study for Mexico’s market is developed to prove the methodology, offering some interesting data about consumption and production of bags and bottles.