Life Cycle Assessment: Why is it Important?

Life Cycle Assessment (LCA), and particularly vehicle product life cycle assessment, is a topic we are very passionate about here at WorldAutoSteel.  So much so that we focus on LCA intensively for the entire month of October across all of our communications channels. Though it’s not an AHSS forming or joining topic, it is one that is critical to truly reducing vehicle emissions for future generations.  Russ Balzer, Technical Director at WorldAutoSteel and our resident LCA professional, in this blog and the next, will talk about LCA, its importance, and the tools WorldAutoSteel has developed to provide environmental insight to design decision tradeoffs.

All over the world there are continuing and growing efforts to address transportation greenhouse gas (GHG) emissions, which remain a major unresolved issue. These efforts are intended to help the transportation sector make its contribution to global emissions reduction goals. Unfortunately, much of this effort is focused on reducing emissions only from the vehicle tailpipe, with no consideration of the other sources of emissions in that vehicle’s life. This is not an effective way to meet these goals. In fact, this approach could lead to the unintended consequence of increasing GHG emissions in some cases. Fortunately, there is a better way – life cycle assessment (LCA), a tool for looking at the environmental impact of a product across its entire life cycle (Figure 1).

Focusing solely on the tailpipe emissions means ignoring other significant sources of GHG emissions, such as vehicle production and emissions generated (or avoided) at the end of the vehicle’s useful life (see Figure 2 on Page 2). An example of this is that tailpipe-only thinking can put too much emphasis on lightweighting. Don’t get me wrong, lightweighting can be an important part of the solution. Three of the four main drivers of fuel consumption (and therefore tailpipe emissions) – rolling resistance, acceleration and gravity (as in climbing a hill) – are dependent on the vehicle’s mass. So we can see why vehicle lightweighting is an obvious choice. It is a direct way to reduce these power demands and achieve better fuel consumption and fewer tailpipe emissions. The problem with lightweighting arises when we are so focused on reducing a vehicle’s mass that we fail to consider the consequences to the vehicle’s overall emissions.

One of the potential consequences arises from the use of lower-density materials like aluminium, magnesium and even carbon fibre to replace steel in a vehicle. From a tailpipe perspective, this can seem like a good (if expensive) solution. Vehicle mass may be reduced, resulting in improved fuel consumption and fewer tailpipe emissions. Sadly, it is not that simple. These low-density materials come with an environmental cost in addition to their higher financial cost. This cost comes in the form of higher GHG emissions in the production of the material itself. On a global average basis, GHG emissions from aluminium production can be as much as eight times as high per kilogram of material as the GHG emissions from steel production. For carbon fibre and magnesium the difference in production GHG emissions is even greater. This means that, even though you may save tailpipe emissions with some applications of these low-density materials, there is always a trade-off of higher production emissions.

In the best case, the reduction of emissions in the use phase does result in overall lower emissions, though, because of the trade-off between the tailpipe and production emissions, not as low as predicted by a tailpipe-only metric. Also possible is an intermediate case in which the use phase savings and the production phase increase are approximately equal, resulting in no net savings at all. In the worst case, the production emissions outweigh the use phase savings, resulting in the unintended consequence—higher overall emissions, the very opposite of what the regulation intends.

All three of these cases have two things in common. First, under a tailpipe-only regulation, we don’t know what the actual emissions are, because production emissions impacts are not being monitored. Second, because the low-density materials we are talking about are more expensive, all three of these cases come at a higher cost. So, we must ask ourselves: do we want to force automakers and consumers to pay more money without knowing the outcome? It’s time to consider another route to reducing emissions, and we believe that taking a life cycle approach is the correct route.

LCA assesses all the stages of a product’s life, from raw material extraction through production, use, and end of life processing. Though awareness of LCA has grown rapidly over the last 10-15 years, LCA methodology and practice have been developing since the early 1970s. Today, it is a mature assessment tool with global standards. Many car manufacturers are already using life cycle thinking and LCA, recognizing its importance and effectiveness in product and process design. LCA is equally accepted and used by material producers. In fact, together with many of their member companies, the trade associations of the steel, aluminium, and plastic industries are among the most active members of the global LCA community.

WorldAutoSteel has been directly involved with LCA since 2007, when we partnered with Dr. Roland Geyer of the University of California at Santa Barbara to develop an LCA tool for the assessment of material choices in passenger vehicles. The UCSB Automotive Materials Energy and Green House Gas (GHG) Comparison Model that Dr. Geyer developed on behalf of WorldAutoSteel is now in its fifth version and continues to be one of the most comprehensive publicly available vehicle LCA tools in the world.

The UCSB model is a full vehicle model assessing both GHG and energy effects of automotive material substitution over the entire life cycle of the vehicle.

Computation and parameter values are kept separate for maximum transparency and flexibility. This allowed the computational structure to be peer reviewed by members of the LCA community. The model calculates 27 main result values: three environmental indicators x three life cycle stages x three vehicles, as shown in Figure 3.

The model has the flexibility to allow a multitude of different scenario evaluations, offering 14 structural material categories, 24 total material categories, adjustable material recycling methodology, a variety of biofuel and electricity pathways, as well as the powertrains, driving cycles and vehicle classes noted in Figure 4.

To maximize flexibility and transparency, all calculations are shown, and no parameter values are locked or hidden. This makes the UCSB Model an excellent tool for teaching LCA, particularly automotive LCA.

GHG emissions in the transport sector must be reduced to meet global emissions reduction goals. Lightweighting of passenger vehicles can be an important part of the emissions reduction solution in the transport sector, but only if lightweighting scenarios are viewed in the context of the overall vehicle emissions. Many companies inside and outside of the transport sector use Life Cycle Assessment, which considers environmental impacts from the whole of a vehicle’s life cycle, as their primary method to develop this overall view. The UCSB Automotive Energy and GHG Model, developed on behalf of WorldAutoSteel, is a publicly available, peer-reviewed tool for the assessment of automotive emissions on a life cycle basis. Version 5 of the UCSB Model can be downloaded for free at the WorldAutoSteel website here.

At the UCSB Model download page, you’ll find a video workshop featuring Russ Balzer explaining the contents of the Model. A user guide is also available for download.

Russ Balzer is the LCA Technical Director at WorldAutoSteel and Phoenix Group. As Technical Director, Russ manages a variety of engineering projects, and has tactical and strategic responsibilities in WorldAutoSteel’s efforts to use and promote Life Cycle Assessment (LCA). Russ recently achieved ACLCA LCACP certification and was recognized for his work in the field of LCA with the ACLCA’s Rising Star Award.