Life Cycle Impacts of Natural Fiber Composites for Automotive Applications: Effects of Renewable Energy Content and Lightweighting

This study examines the life cycle energy demand and greenhouse gas (GHG) emissions associated with substituting natural cellulose and kenaf in place of glass fibers in automotive components. Specifically, a 30 wt% glass-fiber composite component weighing 3kilograms (kg) was compared to a 30wt% cellulose fiber composite component (2.65kg) and 40wt% kenaf fiber composite component (2.79kg) for six cars, crossovers, and sport utility vehicles. The use-phase fuel consumption of the baseline and substitute components, with and without powertrain resizing, were determined using a mass-induced fuel consumption model based on U.S. Environmental Protection Agency test records. For all vehicles, compared to the baseline glass fiber component, using the cellulose composite material reduced life cycle energy demand by 9.2% with powertrain resizing (7.2% without) and reduced life cycle GHG emissions by 18.6% with powertrain resizing (16.3% without), whereas the kenaf composite component reduced energy demand by 6.0% with powertrain resizing (4.8% without) and GHG emissions by 10.7% with powertrain resizing (9.2% without). For both natural fiber components, the majority of the life cycle energy savings is realized in the use-phase fuel consumption as a result of the reduced weight of the component.