Chart 12: Life-time CO2 savings for 100 kg weight reduced vehicles
Life-time CO2 savings [t/100 kg]
Long distance bus
High speed passenger train
freight train freight train
Source: IFEU 2002 from various sources Remark: Error ranges signify the sensitivity to uncertainties in basic data
Road vehicles increase their CO2 saving potentials in comparison to the primary energy savings in our scenario. This is due to the share of nuclear and hydro power, which create almost no CO2 emissions in comparison with energy derived from fossil fuels. For the life-time CO2 savings in Chart 12, it is also assumed that the electricity mix and the emission factors will remain at their current level over the whole life-time of the vehicle. A steady reduction in the CO2 emission factor by 50 % over the life-time of the vehicle means that only 75 % of the CO2 savings stated in Chart 12 will be achieved. While all figures for road vehicles in Chart 12 are calculated for fossil fuels, the share of bio-diesel and other alternative fuel options may be changing as well.
In addition to the direct energy savings by a weight reduction stated so far, indirect en- ergy savings can be achieved by freight vehicles by the transportation of a higher pay- load. In the extreme scenario of a permanent fully loaded truck and freight train, respec- tively, three and four times the direct energy savings can be achieved. In reality, the indi- rect energy savings will be lower, because hardly any truck will drive its entire life-time with a full load. The total energy savings including energy savings by a higher payload will only be significantly higher than direct energy savings if the truck drives a high share of the life-time performance with a full load.
8.2 Potential total energy savings contribution of transport subsystem
In the preceding section, the potential energy savings by the same absolute weight re- duction (100 kg) for typical single vehicles have been calculated. To determine the to- tal achievable energy and CO2 savings by weight reduction we have to take into ac-