Automotive manufacturing costs can be cut by 80% with carbon fiber-based autos vs. steel-based ones due to greatly reduced tooling and simpler assembly and joining. However, such cost savings are currently overshadowed with carbon fiber material prices upwards of $16/lb.
If carbon fiber costs can be driven down to $5/lb (for large-tow, standard-modulus, automotive-grade creel fiber), a carbon-fiber-based auto would become cost-competitive with a steel-based auto. RMI's analysis of composites aligns with studies by MIT and ORNL showing that manufacturing fixed costs can be reduced by 80% from a steel-automotive baseline with composite manufacturing methods. This translates to a 35% overall savings since costs are spread over 250,000 units of annual production. Unfortunately, the same analyses show that all cost reductions associated with body-in-white and/or composite manufacturing techniques are currently overshadowed by higher material cost. For carbon-fiber-based autos to compete with steel ones at the same production volume, carbon fiber costs would need to decrease from their current $16 per pound price by about 60%—yet ORNL thinks this is plausible.
For more, see Projected delivered energy use to manufacture carbon fiber reinforced plastic, Comparison of energy intensity for car manufacturing, and Steel use for automaking.
Fuchs, Erica R. H., Frank R. Field, Richard Roth, and Randolph E. Kirchain. 2008. “Strategic Materials Selection in the Automobile Body: Economic Opportunities for Polymer Composite Design.” Composites Science and Technology 68 (9): 1989–2002.
Boeman, Raymond G., and N. L. Johnson. 2002. Development of a Cost Competitive, Composite Intensive, Body-in-White. Publication 2002-01-1905. Oak Ridge National Laboratory. link