Electrification of vehicles has a good momentum today. However, energy consumption of electrified vehicles is not very much in focus, instead in-efficient electrified vehicles are appreciated on the cost of more energy efficient ICE vehicles. There is talk about a ‘nordic energy mix’, but still almost every single extra kWh of electric energy put in an electrified vehicle in Scandinavia, must be generated by fossil fuels. This needs to come to an end when electrified vehicles become more and more common. In a recently conducted research project [Vehicle – Energimyndigheten project 41213] it was identified that the gear-box has the same loss as the electrical machine. The gearbox is usually a two-stage gearbox, with a gear ratio of 8-12. If a single stage gear-box could be used, the efficiency would go up, however, then the electric machine becomes larger. No gear at all gives best efficiency, but a very large electrical machine. In principle, 1500 rpm at top speed with a power of 100-150 kW is what is needed. Professor Huadong Yao and his collaborators at the Fluid Dynamics division and the Marine Technology division at the M2 department have been devoted to sustainable transport and energy use. The research sujbject focuses on coupled mechanicsms between fluids and solids. And the methodology is mainly numerical simulation. In this project, the numerical method is the Lattice-Boltzmann method and finite volume method. The numerical tools are an in-house LBM solver developed by Huadong Yao, and another solver developed by SAAB Aeronautics for training purpose. Additionaly, STAR-CCM+, ANSYS and OpenFOAM are used for cross comparison of method performance.