The switch to aluminum is gaining momentum.
According to a May report by the consulting firm Ducker Worldwide, the average vehicle built in North America will have about 400 pounds of aluminum in 2015, up from 343 pounds this year.
Aluminum sheet could be especially useful for full-sized pickups, which will have to shed as much as 800 pounds to meet fuel economy standards, according to Richard Schultz, managing director of Ducker Worldwide. Schultz estimates that automakers will be able to make those weight reductions by 2020.
General Motors is expected to be a major user. According to Schultz, GM will use aluminum hoods on its next-generation Chevrolet Silverado pickup, which debuts in 2013. That will save about 25 pounds per vehicle, Schultz estimates.
But the big weight reduction will come when automakers switch to aluminum bodies-in-white. The first to switch were luxury automakers, which could more easily pass along aluminum's added cost to consumers.
The newly launched Mercedes SL roadster, for example, has a 560-pound aluminum body-in-white that cut 300 pounds from the vehicle's weight, according to Novelis, which supplies the aluminum.
Jaguar and Audi also have produced aluminum cars, and the Audi A2 offers a glimpse of aluminum's weight-saving potential.
When the aluminum A2 was introduced in 1999, it boasted a 1,973-pound curb weight. The car was discontinued in 2005. But Audi displayed a four-seat A2 concept in September at the Frankfurt auto show and announced plans to reintroduce it in 2013.
While European automakers have taken the lead, tough U.S. fuel economy standards will force all automakers in the market to consider aluminum-bodied cars.
Alcoa's Schep says: "Every carmaker in the United States is actively looking at an all-aluminum body-in-white."