The requirements for electric vehicles differ significantly from conventional diesel or gas buses. For reliable and economical operation, vehicles must be tailored to their operating conditions from the outset. We calculate vehicle- and route-specific energy demand, considering topography, rotations, climate conditions and passenger turnover. A key focus is on HVAC systems (heating, ventilation, air conditioning, heat pumps), which strongly influence energy consumption. For each temperature range, operating points are defined to balance comfort, efficiency and costs. Traction motorisation is also adjusted: different axle configurations and power variants are compared to optimise driving dynamics and efficiency. Charging infrastructure integration (CCS, pantograph, depot or opportunity charging) is included, as well as support in tenders. Based on requirements, we prepare specifications, review offers and evaluate manufacturer solutions. The result is a coherent overall concept that aligns vehicles, operations and charging infrastructure.