Environmental records: vehicle use

Usually, the use of a vehicle determines the majority of energy use during its lifespan. For vehicles with combustion engines, the majority of emissions arise as exhaust emissions (direct emissions). Although electric vehicles have no direct emissions, the provision of energy greatly influences the environmental record so energy consumption is a crucial factor. Please click on the graph for further information on the different drive trains:

he use of vehicles varies depending on the owner and where it is used. For example, vehicles used in commercial and long-haul transport generally have high lifetime mileage.
Private cars and vehicles used predominantly in urban areas frequently have lower mileage so the environmental effects of manufacturing play a greater role when calculated across the kilometres driven.

The specific energy consumption of the vehicle (per kilometre) also varies significantly. The vehicle model developed and used as part of UMBReLA therefore performs a differentiated calculation of energy consumption and draws on numerous input parameters. The following illustration gives an overview of these (please click on the illustration to enlarge it).

(Please click to enlarge)

Schematic representation of the calculation of energy consumption in vehicle model “eLCAr” (IFEU 2011)

The most important contribution of all energy consumption is the energy consumption at the wheel. This refers to the energy that is physically necessary to move the vehicle and overcome wind resistance, roll resistance and gradients. Furthermore, energy losses arise at different points along the drive train. The effectiveness of combustions engines is restricted to around 40% by basic laws of physics. In electric vehicles, effectiveness is significantly higher at around 90%, although further losses must be considered when charging the battery and because of a relatively high dependence on temperature for overall effectiveness. To give everything comprehensive consideration, the effectiveness of electricity provision must also be considered, and this depends on the mix of refuelling options

Because of the comfort standards of modern cars, auxiliary consumption also plays a significant role, i.e. heating, air conditioning, lights, radio, heated seats etc.
Consumption calculations in eLCAr consider all of these aspects.