A hybrid powertrain system includes a combustion engine, a battery buffer for storing electric energy by converting it onto chemical energy, which can be converted back into electrical energy when need, a fuel cell unit having multiple fuel cells each of which is an electrochemical energy conversion device that converts hydrogen and oxygen into water, producing electricity and heat in the process, a power level control unit for capturing electrical energy from the fuel cell unit for delivering zero power, full power, or any power level in between, and an electric motor having inputs for receiving energy from the combustion engine, the battery buffer and the fuel cell auxiliary power unit, and an output for generating activation power to a transmission providing a driving force to a vehicle.