New Study Confirms Lightweighting Autos with Steel Results in Lower Greenhouse Gas Emissions than Aluminum

November 28, 2018

PITTSBURGH, PA – The use of advanced high-strength steel (AHSS) for large-scale automotive fleet lightweighting results in an immediate and sustained decrease in greenhouse gas (GHG) emissions associated with production and use of the affected vehicle fleet, whereas the use of aluminum for lightweighting the same fleet results in an increase in overall GHG emissions lasting for several decades according to a study (full study available here) released today by the Steel Market Development Institute (SMDI). SMDI is a business unit of the American Iron and Steel Institute.

The study compares a wide range of lightweighting scenarios and, in each case, the use of aluminum would increase overall GHG emissions for many years—offsetting any fleetwide life cycle benefits during the same time period.

Dr. Jody Hall, vice president, automotive market, at SMDI, said, “The study demonstrates that lightweighting vehicle body and closure panels with AHSS immediately decreases overall GHG emissions in the production of the steel for the car and the emissions generated during driving. This study differs from some previous studies in that it takes into account the timing of the GHG emissions, which is a critical consideration in the full life cycle performance of vehicles.”

Based on study findings, Mark Thimons, vice president, sustainability, for SMDI, noted, “When compared to lightweighting with aluminum, lightweighting an equivalent fleet with AHSS instead results in cumulative net savings of more than 300 million metric tons of GHG emissions by 2038–the equivalent of the emissions resulting from combustion of 45 billion gallons of gasoline. By 2053, an additional 100 million metric tons would be saved–totaling more than 400 million metric tons of GHG emissions savings.”

The study incorporated the full life cycle consequences of material selection decisions, including changes in steel and aluminum production, volume of scrap produced and recycled, and use-phase emissions. It augments a 2017 peer-reviewed study from the Steel Recycling Institute (SRI), “Life Cycle Greenhouse Gas and Energy Study of Automotive Lightweighting.”

More information on the studies can be found at, in addition to information on steel’s sustainability and other environmental benefits of using steel.

Jim Woods ( 412-922-2772
Lisa Harrison ( 202-456-7115


AISI serves as the voice of the North American steel industry in the public policy arena and advances the case for steel in the marketplace as the preferred material of choice. AISI also plays a lead role in the development and application of new steels and steelmaking technology. AISI is comprised of 21 member companies, including integrated and electric furnace steelmakers, and approximately 120 associate members who are suppliers to or customers of the steel industry. For more news about steel and its applications, view AISI’s website at Follow AISI on Facebook or Twitter (@AISISteel).

SMDI increases and defends the use of steel by developing innovative materials, applications and value-added solutions for customers in the automotive, construction and packaging markets. SMDI automotive investors include: AK Steel Corporation, Algoma, ArcelorMittal, Nucor Corporation and SSAB Americas. For more information on SMDI, visit or follow @SMDISteel on Twitter.