Interesting they are using a mechanical high pressure pump. It must be a negligible parasitic MPG loss from this.
Kedis The old cam driven fuel pumps had a spring that created the fuel pressure so that the cam only reset the spring for the distance that had been "used" by the spring moving the pump diaphragm that moved the fuel, thus very little loss of energy and the pressure was regulated by the strength of the spring so no bypass pressure relief fuel return was required to regulate pressure. They were low pressure pumps so the high pressure pumps may be different but could use a similar design? The high pressure pumps need more energy so it is more efficient to take mechanical energy from the cam rather than converting mechanical to electric with the alternator and then back to mechanical with an electric pump motor loosing some energy with each conversion.