Currently, carbon fiber reinforced plastic (CFRP) production is about 5 times more energy-intensive per lb than steel production. (Post-1999 advances are rumored but proprietary and not included.)
Energy to manufacture the required CFRP used in the transportation sector ranges between 45 and 120 TBTU/y by 2050. In practice, future reductions in energy intensity and the use of recycled materials will probably further reduce this.
RMI analysis using data from:
A. World Steel Association. 2011. “Selection and Design for Car Door Outer Panel.” Steel University. link
B. Tetsuya Suzuki, Jun Takahashi. 2005. “Prediction of Energy Intensity of Carbon Fiber Reinforced Plastics for Mass-Produced Passenger Cars.” Japan International SAMPE Symposium, December 29. link