A system for driving an environmental control system (ECS) of a vehicle with ground-based electrical power may include a turbine engine on board the vehicle, coupled to the ECS to pneumatically drive the ECS, and an electric machine, on board the aircraft, mechanically coupled to the turbine engine, to drive the turbine engine. A control system such that the electric machine provides motoring assistance to the turbine engine, and that the motoring assistance is limited to match the available current from the ground-based electrical power.