This document discusses the energy requirements and powertrain design for a plug-in hybrid electric vehicle (PHEV). It first estimates the energy needed at the wheels by simulating the vehicle's performance on various drive cycles. It then sizes the engine and electric motor based on these energy needs. For the engine, it selects a 100kW gasoline engine similar to that in the 2010 Toyota Prius. It models the Prius powertrain configuration and calculates performance metrics like acceleration and top speed. Finally, it evaluates the vehicle's emissions and fuel economy on the drive cycles to validate that it meets targets.