Life Cycle Analyses: Part 1

Note: This post was written by SEI staff, Aida Sefic Williams.

“Life cycle analysis” (LCA) is an increasingly common term used in industry and legislation today. Several organizations, such as the U.S. Environmental Protection Agency (USEPA), American Center for LCA, and Electronic Product Environmental Assessment Tool (EPEAT) have started requiring and recommending the use of LCAs. Since the phrase has become very popular, I will venture to clarify what it means and how this effects the electronics industry.

An LCA is a process which looks at the full life cycle of a product or process. When consumers think of a product’s life cycle, they often only consider the manufacturing and use stages of a product. LCAs go far beyond that. They start by looking at the pre-processing stage, which is the stage concerned about how materials are obtained through manufacturing, mining, etc. Next, the manufacturing phase is considered, along with transportation of the product from the manufacturing site, to centralized warehouses and smaller retailers. Following that, the use phase is considered, which usually focuses on energy expediture. The use phase also takes into consideration maintenance and repairs. Finally, the disposal stage is considered, whether that be landfilling, refurbishing, recycling, reusing, and any combination of those processes.

Creating an LCA is a very logical process similar to a simple Scientific Method seen in most middle and high schools. The first step includes setting a scope and definition. Here, you just want to say why you are doing this LCA and what you are trying to accomplish with it. Are you comparing two different steps to see which one uses less energy? Are you trying to see which step in the life cycle is the most environmentally damaging?

Next, the life cycle inventory (LCI) needs to be created. Th LCI is usually very simiar to a bill of materials (BOM) which lists all the materials contained in a product, as well as the quantities of each materials, usually measured in weight. The LCI is important, because it allows an analyst a full view of all the materials that used.

Following the LCI, a life cycle impact assessment (LCIA) is created. The LCIA is one of the most important parts of the LCA process. This step relates the materials listed in the LCI to their invironmental impact factors. In this step, each material listed within the LCI is given an impact factor. Given the impact factors, analysts have a better idea of which materials and processes are the most harmful. For example, if you have materials A and B in a process, they are each assigned their respective impact factors, which are usually measured in a “per unit of mass” (i.e. per gram, per kilogram).

If we have Materials A and B in a specific process, each material will be given an impact factor. Assume we have 2g of material A and 10g of material B, we cannot immediately assume that material B is worse for the environment. Assuming that the impact factors for materials A and B are 5.1 and 0.2 g CO2/g of material, respectively, we are left with the following conclusion: Material A emits 10.2g of CO2 and material B emits 2g of CO2.

Finally, it is time to look at the results and make any necessary conclusions. Once we know the impact factors of all the materials, it can easily be identified which materials emit the most environmentally damaging products. Once this conclusion is drawn, the next step is to recommend design or process changes which will minimize or eliminate the use of the more hazardous material. Given a complete life cycle analysis, designers and analysts have an opportunity to work together in order to make products more sustainable and better for the environment not only during the manufacturing or use phase, but in regards to the complete life cycle of a product or process.

More about the advantages and pitfalls of life cycle analyses next week.

You can also use the LCA Calculator to create the LCA of a product.

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