CHICAGO Aluminum-intensive vehicles impact the environment less than lightweight steel cars and trucks, according to an Oak Ridge National Laboratory (ORNL) study underwritten by the Aluminum Association.
The key reason is increased fuel-economy resulting from aluminum slashing vehicle weight during the "use phase," the period when a car or truck is on the road, according to the study, which was led by ONRL researcher Sujit Das.
The Steel Market Development Institute (SMDI), a business unit of the Washington-based American Iron and Steel Institute, has concerns about the study but is withholding comment until it has more information about the research, SDMI president Lawrence Kavanagh said. "Were going to make a very rigorous academic and engineering assessment of both the assumptions and the conclusions," Kavanagh told AMM Sept. 20. "The devil is in the details."
Although aluminum is lighter than steel,the production of primary aluminum requires large amounts of electricity. But while lightweight steel vehicles impact the environment less during their "production phase"when steel for the cars and trucks is being madethat lower initial impact is offset by higher energy requirements and more carbon dioxide emissions during the use phase for steel vehicles, the study said.
"As the U.S. works to reduce dependence on foreign oil, promote clean energy and combat climate change, this report definitively documents why aluminum offers the most promise for cutting total automotive-related carbon emissions and energy use," Das said in a statement Sept. 19, the day results of the study were made available to the public.
An aluminum-intensive vehicle reduces mass by 28 percent and, during the use phase, cuts energy consumption by 32 percent and reduces carbon dioxide emissions by 29 percent, the study said.
In addition, an aluminum-intensive vehicle reaches a "break-even" point, when energy used during the production phase is offset by energy saved while the vehicle is on the road, after 9,300 miles compared with 30,000 miles for a lightweight steel vehicle, the study said.
The Aluminum Association cheered the results, noting that most vehicles in the United States are driven more than 9,300 miles in their first year on the road.
"This study adds even more evidence that switching car bodies from steel to aluminum is the next logical step for carmakers to take in the drive to reduce emissions," Randall Scheps, chairman of the Aluminum Associations Transportation Group and automotive marketing director for Pittsburgh-based Alcoa Inc., said in a statement, adding that aluminum has already been shown to be safe, durable and cost-effective for car bodies. "Now ORNL has shown that aluminum is better than steel on a full lifecycle CO2 basis. That is the icing on the cake."
ONRL is managed and operated for the U.S. Department of Energy by UT-Battelle LLC, a nonprofit, 50-50 limited liability partnership between the University of Tennessee and Battelle Memorial Institute, according to its website.