Full Vehicle LCAs: A Review

A review has been conducted on nine published full vehicle life cycle inventory studies. Our analysis shows that all studies conclude that the vehicle operational stage is dominant regarding energy and associated emissions. For energy this ranges between 60-80% of the total burden, the magnitude of which is dependent on the efficiency of the powertrain. On the other hand, for burdens like solid waste, the material production stage of the life cycle is dominant. When life cycle burden results are decomposed into fixed and variable components per mile driven, it is found the variable energy and associated stoichiometric emission (CO₂) results demonstrate the underlying physics of vehicle propulsion, i.e. they are dependent on vehicle weight and powertrain efficiency. On the other hand, the fixed component of energy and CO₂ shows more apparent scatter, which can, nevertheless, be reconciled on the basis of vehicle material composition and vehicle lifetime drive distance. For SOx, hydrocarbons and solid waste, fixed and variable life cycle burden components generally showed increasing trends with vehicle mass. Unfortunately, not enough data of sufficient quality is available to determine reliable values for these trends. Hence, average values for them are reported. Finally, it apparently takes more energy to fabricate a vehicle in North America than in Europe or Japan.