The case studies examined the effect various automotive materials can have on total life cycle greenhouse gas emissions. The studies used the Automotive Materials Energy and GHG Comparison model, and investigated whether an AHSS-intensive design would result in fewer emissions than an aluminum-intensive design, compared to a conventional steel baseline, when looking at the entire vehicle life.
In each vehicle’s best performance case, the steel design showed decreased total life cycle emissions over the aluminum vehicle by 3 percent for the light-duty truck and 5 percent for the SUV, according to Russell Balzer of WorldAutoSteel.
For a fleet (annual production of 700,000 trucks; 200,000 SUVs), if both vehicles were manufactured in AHSS, it would equate to approximately 1.7 million metric tons of total emissions savings over the aluminum-intensive vehicles.
The AHSS and aluminum designs reduced structural weight by 25 percent and 35 percent, respectively. For both the truck and SUV cases, the AHSS designs were within 70 kilograms of the aluminum weight savings.
There was not a significant difference in fuel consumption between the two materials.
According to Balzer, from a lightweighting perspective, the AHSS-intensive vehicles produce fewer emissions on a life cycle basis than aluminum-intensive ones because the primary production of steel, including AHSS, produces seven to 20 times fewer emissions than other materials such as aluminum, magnesium and carbon fiber reinforced plastics.
Currently there is a strong emphasis on lightweighting in the automotive industry as a means to reduce emissions. Last year, Chuck Evans, corporate vice president at Henkel’s automotive group, said that lightweighting is the automotive industry’s best bet to achieve the 2025 corporate average fuel economy standard.