In Steer-by-Wire (SbW), the mechanical connection between the Steering Wheel and Road Wheel is not present anymore; therefore, the steering power must mimic this missing connection virtually only. This is also leading to enhanced steering power and power supply requirements. These requirements need to be developed in the context of normal vehicle operation but also for operation at degraded modes in case of a fault. Additionally, typical automotive environmental conditions are challenging for the power supply architecture. For intact systems, the derivation of requirements includes typical use cases like parking and driving, hence peak power, slew rates and average power demand are key parameters. Generally, safe power supply architectures for SbW require a redundant power supply. This includes performance requirements for a safe vehicle degradation after a fault, requirements for the period of continued driving after a fault and requirements for the minimal energy storage to reach the safe state on vehicle level. Exemplarily, for Battery Electric Vehicles, a power supply specification landscape for a SbW system will be presented and future challenges are identified.