DOE OSTI2016
Vehicle lightweighting reduces the amount of fuel consumed in a vehicle's use phase, but depending on what lightweight materials replace the conventional materials, and in what amounts, the manufacturing energy may increase or decrease. For carbon fiber reinforced polymer (CFRP), a next-generation lightweighting material, the increase in vehicle manufacturing energy is greater than the fuel savings, resulting in a net increase in energy consumption over a vehicle's manufacturing and use relative to a standard non-lightweighted car. [1] This work explores ways to reduce the supply chain energy of CFRP lightweighted vehicles through alternative production technologies and energy efficiency improvements. The objective is to determine if CFRP can offer energy savings comparable to or greater than aluminum, a conventional lightweighting material. Results of this analysis can be used to inform additional research and development efforts in CFRP production and future directions in lightweight vehicle production. The CFRP supply chain is modeled using the Material Flows through Industry (MFI) scenario modeling tool, which calculates 'mine to materials' energy consumption, material inventories and greenhouse gas emissions for industrial supply chains. In this analysis, the MFI tool is used to model the supply chains of two lightweighted vehicles, an aluminum intensive vehicle (AIV) and a carbon fiber intensive vehicle (CFV), under several manufacturing scenarios. Vehicle specifications are given in [1]. Scenarios investigated cover alternative carbon fiber (CF) feedstocks and energy efficiency improvements at various points in the vehicle supply chains. The alternative CF feedstocks are polyacrylonitrile, lignin and petroleum-derived mesophase pitch. Scenarios in which the energy efficiency of CF and CFRP production increases are explored using sector efficiency potential values, which quantify the reduction in energy consumption achievable when process equipment is upgraded to the most efficient available. Preliminary analyses indicate that producing CF from lignin instead of polyacrylonitrile, the most commonly used feedstock, reduces energy consumption in the CFRP supply chain by 7.5%, and that implementing energy efficient process equipment produces an additional 8% reduction. Final results will show if these potential reductions are sufficient to make the CFV energy savings comparable with AIV energy savings. [1] Das, S., Graziano, D., Upadhyayula, V. K., Masanet, E., Riddle, M., & Cresko, J. (2016). Vehicle lightweighting energy use impacts in US light-duty vehicle fleet. Sustainable Materials and Technologies, 8, 5-13.
29 ENERGY PLANNING, POLICY, AND ECONOMY↗