Activity-based life cycle assessments in design and management.

摘要

Life-Cycle Assessments (LCA), which can be defined as an approach to assess environmental: impacts throughout the life-cycle of product systems, are important in environmental management. However, current LCA methods do not yield comparable results, something industry demands, to mention one problem. We therefore design a LCA method that yields comparable results. We utilize modern cost management practices and expand them to handle environmental impacts in terms of energy consumption and waste generation. Waste generation is measuring' the efficiency of which materials are converted into useful products, while energy consumption is measuring how energy efficient this conversion is. Our main contributions are (1) a new LCA method called Activity-Based LCA and (2) a new environmental indicator called the Waste Index (WI): (1) Activity-Based LCA is an extension of Activity-Based Costing because costs, energy consumption and waste generation are handled in an integrated activity-based framework. Also, the attention directing capabilities are enhanced by purposely adding uncertainty to the models, employing Monte Carlo methods and sensitivity analyses. The usage of Monte Carlo methods allows easy uncertainty handling and the effects of distortions in assessments are also illustrated. Finally, the assessments and identification of critical success factors are linked to product- and process design. (2) The Waste Index is based on the laws of thermodynamics and chemistry and it therefore yields comparable results. The axiom behind the WI is that ‘environmental impact can only be measured relatively by benchmarking Nature’. This represent a paradigm shift in environmental impact assessments since conventional indicators always relate the assessments to specific environmental problems which are inherently incomparable.; We use four case studies to validate the research: (1) Toy manufacturing at a simulated factory called WagonHo!, Inc., (2) Platform Supply Vessel (PSV) operation by Farstad Shipping ASA, (3) flooring systems manufacturing at Interface Flooring Systems, Inc. and (4) mattress- and bed manufacturing at Westnofa Industrier AS. Activity-Based LCA and the Waste Index proved very useful in providing comparable and accurate results, good tracing and attention directing in all these case studies. From this we conclude that Activity-Based LCA is a major improvement over current LCA methods.