Life Cycle Thinking: Key Issues and Indispensable Tools, by Lloyd Hicks It's important for designers to recognize the impact made in every phase of a product's life cycle. In this case, shifting agricultural practices may result in the most significant emission reductions, but designers are far from powerless to make improvements. The same study states that packaging and distribution represented 37% of the carbon footprint. With that in mind, how could a designer accurately test new scenarios to create an orange juice distribution strategy that has fewer impacts on the environment? How would he or she know if a plastic bottle is better than a gable-top carton or not? How do concentrated juice products size up? Every stage in the product's life cycle has potential impacts on the environment; LCA gives designers the ability to make informed decisions to reduce those impacts. These types of questions are challenging because of the complexity of real world factors; the formulation of appropriate answers requires powerful analyses, databases and tools. Fortunately, within the last year, applying life cycle thinking has come within the reach of any designer. We now have the tools to help us assess the life cycle environmental impacts of our designs before they are produced and to improve upon products that already exist. This gives us insight into the orange juice delivery problem, at least for a start. Life Cycle Assessment As LCA continues to evolve, so too do its key issues. To gain a better understanding of these, I interviewed consultants in the life cycle field and asked them to share stories from their work. The resulting case studies follow; after that, I'll introduce several tools designers can use to systematically assess the environmental impacts of their products. Timberland's Green Index Each shoe is rated from best to worst in three environmental areas: climate impact, chemical use and resource consumption. After setting a baseline Green Index score, Timberland set targets for reductions in energy use, waste generation and solvent use. They have goals to increase the use of organic cotton, renewable materials, recycled content and improve the environmental performance of their factories. Questions were raised about the data sources in LCA tools. Was the data representative of the factories that Timberland sourced material from? Gloria says that most consumers still evaluate a companies' products by performance, function and price, but a growing number of customers want to know a company is making progress in environmental areas. The Green Index labeling can help show this progress. Well before Timberland's customers started to see the Green Index rating system and corporate-wide, quarterly key performance indicators, there were internal discussions about the most significant environmental aspects as a company. Questions were raised about the data sources in LCA tools. Was the data representative of the factories that Timberland sourced material from? After investigating, Timberland decided to use average industry data to calculate the climate impact of raw material production and factory-specific data on energy use that accounts for the power delivered from the regional electricity grid. According to Gloria, using industry averages in LCA as a proxy definitely has its benefits due to the relatively low costs of obtaining the data. Yet, when it comes to making some large capital expenditures to change materials, processes or suppliers, the argument is much better if you've got the factory-specific data to back it up. Seventh Generation Greiner looked closely at the life cycle impacts of Seventh Generation's detergent. He had greenhouse gas factors for nearly all of the product formula and transport stages. Data had to be calculated for the use and disposal phases, including: washing machine use, hot water heating, drying and treatment of the waste water generated by washing. There many limitations to gathering better data, and the further a company goes up its supply chain, the less leverage it has. Greiner found that the consumer use phase—washing machine use, heating hot water and drying the load—used the most energy and had the highest greenhouse gas impact—roughly 95% of the greenhouse gas emissions generated for an average load of laundry in the US. With these findings and the strong communication channels Seventh Generation had with their customers, it became clear that changing customer behavior was a top priority, as the detergent is specially formulated to have the same cleaning effectiveness in both hot and cold water cycles. Greiner also touched on his experiences with data sources in LCA tools. To help determine data quality requirements for materials, he often considers the percentage of a total product's weight. For example, a material that makes up 40% versus 1% of a product's weight may need greater attention. The company could then take this information to its suppliers to determine if the data was representative of their operations or if there were marked differences. He pointed out that there many limitations to gathering better data, and the further a company goes up its supply chain, the less leverage it has. For commodity materials such as detergent surfactants, a purchaser generally only knows the region, and in some cases may not even know that. Regional specificity and thresholds for emissions and water use from production processes are not usually available. When a number of companies are interested in the attributes of a specific commodity material-palm oil, for instance—Greiner believes industry standards can play a role, much like we buy 'green' power. When a number of companies collaborate on industry standards, the benefits become more compelling for suppliers. Products from Biomass-based crops According to Hamilton, companies that create products from biomass-based crops often think their products are naturally better than the petrochemical-based alternatives, but discover the impacts from intensive land use, fertilizer use and pesticide application are much higher than expected. This depends on the resources used in growing those plants, and LCA can help identify critical areas to focus on during the production of these products. There are a number of impact methodologies to choose from, but each yields different results depending on value choices and the emissions measured. She also points out that there is variability produced by the impact methodologies within LCA. These are consensus-based approaches decided upon by life cycle practitioners and scientists that convert emissions into human and environmental impacts. There are many to choose from, but each yields different results depending on value choices and the emissions measured. It is important for companies to select one that is relevant for the product studied, and to compare results across methods. Treatment of biomass-based crops might produce either favorable or unfavorable results for a product depending on the selected methodology, for example. The control of this variability grows with the sophistication of the LCA tool. In more advanced systems, the user may specify how emissions are translated into impacts. Summary of the Uses of LCA To summarize, key uses of LCA by practitioners include determining and monitoring the most significant environmental aspects; establishing a baseline for comparison, labeling impacts and setting corporate goals; and considering all life cycle impacts, including changing customer behavior in the use phase. These same practitioners are making important contributions to LCA by seeking industry standards to create more compelling benefits for suppliers to change practices; mastering the selection of appropriate data sources (industry-averages versus factory-specific); and becoming aware of the need for and developing transparent methodology.
LCA Tools Projects ranged from a vertical grow-light system for plants to a vermicomposting bin. After establishing which elements each product should be evaluated and compared by (e.g., providing light for indoor plants or the material for containment of food scraps), users also indicate how long this service will be delivered. Next, data pertaining to material selection, production methods, transport distances and end-of-life assumptions are entered. Sustainable Minds makes it easy to upload a bill of materials from AutoDesk's Inventor (as well as other 3D modeling programs), so no manual entry is necessary for the material selection stage. Once the life cycle stages are filled in, the results are broken down in easy-to-read to charts, giving a quick idea about where the impacts are in the product life cycle. Add as many concepts as you want and compare any two of them side by side. Sustainable Minds also has an expansive section of the website dedicated to helping designers understand eco-design strategies that may help reduce the impacts revealed by the software. What might one learn from Sustainable Minds? In the simple case of the vermicomposting bin, for instance, my student had to make an argument for the extra materials and processes that went into her more user-friendly, visually pleasing design. Do-it-yourself worm bins simply use a plastic bin with a lid and some holes cut out. She designed her bin to be left out in the kitchen instead of tucked away in a closet. But would her worm bin last longer before being tossed out? Though her design was relatively worse for the environment, she used Sustainable Minds to show when things would tip in her favor due to a long-lasting product that people wanted to keep. Greenfly includes a set of design guidelines that prompt users to think about goals related to: dematerialization, low impact material selection, cleaner production, optimized distribution, design for durability, use phase impact reduction, and design for waste avoidance and resource recovery. Next, Solidworks has taken another direction by including an add-on called SustainabilityXpress directly in the modeling environment. In this version individual parts are assessed with the environmental impacts shown right within the 'impact factor dashboard'. A more advanced version, Solidworks Sustainability, is available for purchase. It allows users to assess entire assemblies, enter data on the use phase and transport modes, and determine components with the highest impacts from the bill of materials. Both versions allow users to set baselines for comparison and generate reports in a couple key impact areas.
GaBi requires users to build a 'process-tree' to connect materials, energy and processes to parts. After building the product system in GaBi, users can check if inputs and outputs match up for the assemblies. In SimaPro, after data for the product system is entered in, users can switch to a flow chart view to easily see the relative impacts from materials and processes. Both tools can display inputs/outputs and impacts in what appears to be every conceivable format. Training and/or tutorials are available for GaBi through PE International and SimaPro through EarthShift. SimaPro and GaBi allow users to select from a number of impact methodologies. The single-indicator systems, like the one used in Sustainable Minds, can also be utilized here, along with common individual impact categories such as global warming potential, acidification potential, eutrophication potential, etc. The Bottom Line on LCA Tools |
【翻译】关于产品生命周期的思考
2010/08/06 00:59 A.M.