LCA Phase 1: Goal and Scope Section 3: How do practitioners set up and begin a Life
Cycle Assessment?
With an understanding of how to establish the goal and scope of a Life Cycle Assessment, we can begin to practice establishing LCA study design parameters by identifying the LCA objective, formalizing the target of the study, and identifying the system boundaries. In this example, a team is investigating the sustainability of single­serve coffee makers, like the popular Keurig coffee maker. The following two videos and the text below will walk you through the steps of setting up an LCA for the single­serve coffee maker example. Session 6: Setting up an LCA (​69:24­78:42 ONLY​) ME 589 | Professor Steven Skerlos WATCH HERE Session 7: Setting up an LCA (​5:27­25:45 and 34:38­80:20 ONLY​) ME 589 | Professor Steven Skerlos WATCH HERE The team first thoroughly establishes the goal of their study by outlining why they are conducting the LCA, what the study will be used for, who the intended audience is, and if the LCA will be comparative with assertions disclosed to the public: A. Identify the LCA Objective 1. Why are we conducting an LCA? Manufacturers of single­serve coffee makers claim that they are a more "sustainable" alternative than conventional multi­serve coffee makers. However, there are concerns with increased solid waste from packaging, and potentially other usage­related factors that lead us to question this notion. To answer this question definitively, we choose to perform an LCA on both types of coffee makers under different usage scenarios. 2. What will the LCA be used for? The LCA will be used to determine which set of parameters in the life cycle of a coffee maker govern or affect specific environmental or economic impact metrics most significantly. Additionally, the LCA would also determine under what set of value for these key parameters does the single serve coffee maker perform better (if at all).
3. Who is the intended audience of the LCA? Coffee drinkers and companies designing and manufacturing coffee makers. 1 LCA Phase 1: Goal and Scope 4.
Will the LCA be comparative with assertions disclosed to the public?​ Yes, the LCA along with its assumptions will be made available to general public as a peer­reviewed conference or journal publication. After creating a clear goal, the team starts defining the scope of the LCA study by stating the function of the system, the functional unit, and the reference flow: B. Formalize the Target of the Study
1. What is the function of the system? To provide hot coffee. 2. What is the functional unit of measure that will define the scale of the LCA? Service provided by a coffee maker to a household with two adults over a period of one year. 3. What is the reference flow? 691 liters of medium roast (regular strength) coffee produced over a year. This number is obtained by assuming a consumption of 2.67 twelve ounce cups per person per day on average, which accounts for seasonal variation on coffee consumption over a year. The team goes on to further outline the life cycle stages, time, and geographic boundaries, what criteria will be excluded from the scope of the LCA study, what impact categories will be included, what goods/infrastructure will be included, goals for system data, assumptions expected to be made in the study, and limitations of the study:
C. Identify System Boundaries What life cycle stages will be included in the scope of the study? ​ Material extraction, processing, and distribution of coffee maker components; production, roasting, and distribution of coffee and other consumables during the use phase of the coffee maker; energy use during use phase; end of life of the coffee packaging. However, since the study is comparative, only differing components and materials between the conventional and single serve coffee maker designs will be modeled in all the stages of the life cycle described earlier. 2. What time and geographic boundaries are placed on the system? Coffee maker is assumed to be produced in China, coffee beans are assumed to be produced in Brazil and roasted locally in Ann Arbor. Geographic variations in processes beyind these are ignored or aggregated as per assumptions of the Ecoinvent database in Umberto. Time variance of emissions and their impact on the environment are included to the extent that mid­point impact characterization factors in the TRACI 2 method do so. 3. By what criteria will LCA elements be excluded? 1.
2 LCA Phase 1: Goal and Scope 4.
Components that are small and have negligible mass and/or volume will be excluded from the study unless they have significant toxicity or human health impacts on account of the materials used in them or the processing of the materials contained in them. What impact categories do you plan to include?​ Non renewable energy use, fresh water use, smog, acidification, ecotoxicity, global warming, eutrophication, human health impacts, and solid waste generation. Will capital goods/infrastructure be included? Capital and infrastructure goods will be excluded for all components of the coffee maker, use phase materials, and coffee production. 6. What goals do you have for the age of data used and its representativeness for your system? As far as possible, life cycle data for materials in the coffee maker will be used from the most updated Ecoinvent 3.0 database. Usage data for the coffee maker will be modeled based on the average coffee drinker's consumption pattern using surveys. For the coffee production data, values from studies published between 2000 and 2010 years ago will be used. 5.
If survey data is not possible to obtain in a timely manner, assumptions about consumption patterns will have to be made. The source of coffee production and place of coffee consumption will be assumed, and will be specific to this study.
7. What assumptions do you expect to have to make? 8. What limitations do you expect your study to have? Uncertainties in coffee production would not be be fully captured; the LCA will be attributional and hence will not capture any consequential or marginal impacts of coffee production and consumption.
References
Skerlos, S. (2016). Session 6 and Session 7: Setting up an LCA. Mechanical Engineering 589. University of Michigan. Retrieved from http://leccap.engin.umich.edu/leccap/site/qke504mycf187470k9h 3