Life Cycle Assessments and E85

Past posts on this blog have often praised the clean air benefits of choosing to use E85 in your flex fuel vehicle or even opting for 88 octane (E15) instead of 87 octane in a 2001 or newer gasoline vehicle. In a two-part series this week, we’ll begin to share scientific evidence behind these clean air claims. Today, in Part I, we will introduce a method used to weigh costs and benefits, a process known as a life cycle assessment (LCA). In Part II later this week, we’ll discuss a specific type of LCA called the GREET model, which was developed by the U.S. Department of Energy to assess and compare petroleum use and alternative fuels. We’ll also discuss results of E85 used in this GREET tool and address other considerations when looking at the air quality impact of using E85.

Part I: What is a Life Cycle Assessment and Why Does it Matter for E85? 
 According to the International Organization for Standardization (ISO), “A life cycle assessment is the assessment of the environmental impact of a given product throughout its lifespan.” Sometimes called cradle-to-grave assessment, ISO further defines LCA as “a compilation and evaluation of the inputs, outputs, and potential environmental impacts of a product system throughout its life cycle. LCAs address the environmental aspects and potential environmental impacts throughout a product’s life cycle, from raw material acquisition, through production, use, end of life treatment, recycling, and final disposal.” In other words, LCAs allow us to see a picture in its entirety—not just partial segments. For instance, when considering the full life cycle of E85, we would take into account the energy use and emissions created during the planting and harvesting (agricultural processes), the production of ethanol in a refining facility, all the way to the delivery of the product to the station/pump, emissions created by its use in vehicles, and more. The results can then be compared to petroleum’s life cycle starting at the drilling site through to refining, distribution, and use in a vehicle. This is also sometimes referred to as a “Well to Wheels” analysis.

So why does an LCA matter for E85? Well, there’s pretty solid research depicting fewer tailpipe emissions with burning E85 than burning petroleum-based fuel (we’ll detail more of this research in future posts!). However, what comes out of the tailpipe is only one segment of the product's life cycle. So you may want to know, “Is E85 still better for our air even when accounting for energy and emissions from ethanol's agricultural and refining processes?” The answer is yes. Evidence to support this can be captured through use of the GREET model. This comprehensive LCA model allows us to examine every stage in the process and get a full picture of E85’s “life” and not just the tailpipe emissions. We can use this same tool to evaluate petroleum based fuel lifespan—from wells to wheels—and can then compare the results to see which produces fewer life cycle greenhouse gases. Check back on Friday for Part II of this series, and a more detailed look at GREET.

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