Electrified powertrains for wheel-driven non-road mobile machinery

Already enacted carbon-dioxide (CO2) limiting legislations for passenger cars and heavy duty vehicles, drive motivations to consider electrification also in the sector of non-road mobile machinery. Up to now, only the emissions of the vehicles themselves have been restricted. However, to capture the overall situation, a more global assessment approach is necessary. The study described in this article applies a tank-to-wheel and an extended well-to-wheel approach based on simulations to compare three different powertrains: a battery electric drive, a parallel electric hybrid drive, and a series electric hybrid drive. The results show that electrification is not per se the better solution in terms of keeping CO2 emissions at a minimum, as battery electric powertrains are accountable for the lowest as well as the highest possible CO2 emissions of all powertrains compared. A battery electric machine is not economically competitive if its battery has to last a whole working day. Parallel hybrid systems do not achieve much of an advantage in terms of CO2 emissions. In this global assessment approach, the most promising propulsion system for wheel-driven-mobile-machinery appears to be the series hybrid system, which shows to offer up to 20% of CO2 saving potential compared to the current machine.