It's a half hearted effort in my view, it retains the standard axles, gear boxes and propshafts all of which are very inefficient. A proper effort would have a motor on each wheel, get rid of the live axles and get far more ground clearance and simulate CDL electronically - BIG increase in efficiency, they just re used the components they had as it is only a publicity stunt.
I seem to recall Chrysler built a lemans car poered by a small gas turbine running at constant speed, this used an electric motor to spin up a flywheel which stored the power (at 50,000 rpm I think) This car could do several laps of Lemans without the turbine running, shame they quietly shelved it, with todays engineering it could be an answer.