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Clearing the air on metals and carbon emissions

Keywords: Tags  Heidi Brock, Aluminum Association, aluminum, automotive, steel, emissions, carbon

To the Editor:

With continuous advances in alloys, design, joining technologies and recycling, aluminum producers unquestionably upended the status quo and are being rewarded with historic market share gains. The steel industry and other material providers, likewise, are evolving their products such that we all contribute to the multi-material approach automakers are adopting to meet or exceed forthcoming higher federal fuel economy and emissions standards. Through our collective efforts, consumers get new cars and trucks that are safer, increasingly sustainable and exciting to drive. 

However, the aluminum industry is compelled to respond to information about our products that is demonstrably incorrect. The steel industry wrongly claims, based on its own life-cycle assessment, that when all vehicle life-cycle phases are considered, advanced high-strength steel (AHSS) produces a smaller total carbon footprint than aluminum. 

Consider the following: 

• In 2014, the U.S. Energy Department’s Oak Ridge National Laboratory in Tennessee studied life-cycle carbon emissions, and its peer-reviewed report concluded that “a proven way to reduce the carbon footprint of vehicles is to further increase the use of lightweight materials, such as aluminum alloys, in place of heavier, less-efficient steels. A full life-cycle environmental analysis confirms that—when compared with both traditional and advanced steels in the areas of cumulative energy demand, potential ozone depletion and other likely factors in climate change—aluminum rises to the top as the best choice for the environment.” 

• Last year, Ford Motor Co., Dearborn, Mich., and Magna International Inc., Aurora, Ontario, released a life-cycle assessment comparing a 2013 Ford Fusion to the Mach-I, a prototype lightweight aluminum-intensive sedan that achieved an overall 23-percent vehicle mass reduction and a combined fuel economy of 34 miles per gallon (vs. 28 mpg for the steel-bodied Fusion). This confirmed that by using an aluminum-intensive design, a high-strength steel-bodied car that has reached its maximum fuel efficiency limit can further lower its environmental impact. 

• Recently, the steel industry has touted the fact that producing primary aluminum is more carbon intensive than producing primary steel. This argument, while true, is fundamentally misleading and misses the point entirely from a life cycle assessment perspective. Automakers know that it takes far more steel by weight to do the same job as aluminum in an automobile part. For example, in closures and body structures, one pound of aluminum typically replaces 1.6 pounds of steel. This significantly minimizes the up-front material production impact. Coupled with energy savings through increased fuel economy on the road and 90 percent plus end-of-life recycling rates for aluminum auto parts, aluminum-intensive vehicles have a lower lifetime carbon impact when compared with both traditional and advanced steels.

• The steel industry’s life-cycle assessment is premised on old data. The steel industry relies on outdated aluminum data from 2008 with a nearly 20-percent over-calculation of aluminum’s energy and carbon footprint, despite the fact that more-recent, peer-reviewed aluminum data from 2013 is publicly available. Current data confirms a nearly 40-percent reduction in carbon emissions for North American primary aluminum production since 1995 and growing use of renewable hydroelectric power to 75 percent of capacity today from 63 percent in 1995. 

• The steel industry significantly downplays mass reduction achievable with aluminum, and overplays mass reduction achievable with AHSS. It wrongly assumes auto body mass reduction potential (body-in-white and closures) of 25 percent for AHSS and 35 percent for aluminum from a mild steel baseline. Production design studies from automakers themselves, including those from Jaguar Land Rover and the aforementioned work by Ford and Magna, consistently find mass reduction potentials of approximately 20 percent for AHSS and 40 percent for aluminum. 

 • The steel industry considerably downplays mass reduction-induced fuel savings for vehicles by using a lower factor for the fuel consumption impact of mass reduction than generally agreed upon throughout the automotive industry, underestimating the impact of mass reduction by 25 to 30 percent. 

• The steel industry assigns end-of-life recycling rates that significantly under-estimate both steel’s and aluminum’s real world recycling rate. The steel industry life-cycle assessment model uses a “multi-step recycling rate” with steel at 77 percent and aluminum at 69 percent. A study by the U.S. Geological Survey confirms that recovery of post-consumer automotive metals in North America exceeds 90 percent regardless of material (steel, aluminum, copper, magnesium, stainless steel). 

 One material will no longer exclusively own the automotive market and our customers demand and deserve supplier-based solutions. The aluminum industry embraces this multi-material challenge and accepts the fact that steel, carbon fiber, magnesium and others, along with aluminum, all play a role in future vehicle design. Credibility is the key to continued success in this evolving automotive market, and it is up to our customers and industry observers to determine which issues are most important and to demand fact-based dialogue. 


President and chief executive officer 

Aluminum Association

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