Remember BMW’s Vision EfficientDynamics concept from a few months back? The design used a 265kW three-cylinder diesel engine matched to a lithium-polymer battery stack and two electric motors. German website and newspaper Auto Zeitung is speculating the possibility of BMW now using the 5.0-litre V10 from the E60 M5 though, which would turn the ultra-green hybrid into a super-green supercar.

Rumour has it the 378kW V10 would be accompanied by a 60kW electric motor at the front axle and a 37kW motor at the rear axle. The result? 475kW. Sources expect a 0-100km/h time of under four seconds too. Even more remarkable though, with the addition of those electric motors – which would also be powered by the same lithium-ion battery stack as the diesel concept – the supercar should be able to achieve an average fuel consumption of about 3.7L/100km.

Sources also say the front motor will be capable of short boosts in power providing up to 86kW, further increasing the car’s tendency to supply supercar-like performance. The batteries are said to need  just 2.5 hours to charge at a general power socket and give the electric motors enough juice for about 50km, alone. So the supercar could actually be driven using only battery power.

The 2-plus-2 seating arrangement will mean the car weighs  in at around 1500kg, but it will be built using light-weight, exotic materials such as aluminium for the chassis, carbon-fiber for the panels and polycarbonate for the windows.

The concept is believed to be under development and could hit the showrooms by the end of 2013. Expect an M-like price tag of $300,000-plus.