2 Executive Summary
This study deals with the energy savings during the operational life of weight reduced transport vehicles. A weight reduction directly reduces the energy consumption be- cause the energy required to move a vehicles is, except for the aerodynamic resis- tance, directly proportional to the weight of the vehicle, thus avoiding environmental im- pacts of all upstream activities (fuel supply, energy conversion in the engine, etc.). The potential life-time energy savings depend on the specific energy savings and the life- time performance of the respective vehicles.
The total energy consumption and savings of a vehicle are also determined by the effi- ciency and impacts of the transmission, engine and energy supply. Differences mainly depend on the energy carrier used. To allow for a comparison of the results we will determine the primary energy savings which take into account the efficiencies of transmission, engine and energy supply.
As a first step, the specific primary energy savings by a 100 kg weight reduction and the life-time performance of selected, “typical” vehicles for each category are compared using simulated and measured data from literature, statistics as well as ex- pert estimates. It must be mentioned that an absolute weight reduction by 100 kg im- plies different relative weight reductions with respect to the total weight of the vehicle and therefore has a different significance.
Cars (gasoline) Cars (diesel) City buses Long distance buses Articulated trucks
Subways/ Urban trains Regional trains Long distance passenger trains High speed passenger trains Long distance freight trains (electric) Long distance freight trains (diesel)
Subsequently, the life-time primary energy and CO2 savings of the representative vehicle examples are calculated. Additionally, the life-time primary energy savings of 10 % weight reduced new registrations of one year are calculated exemplary for the situation in Germany. The following road and rail vehicles have been selected for a comparison in this study: