Both the X6 Hybrid and 7-Series hybrid models have been teased in the form of concept studies in the past. It is expected that they will share the same two-mode hybrid system that combines electric motors with an advanced automatic transmission and a conventional gasoline engine, most likely the 407HP 4.4-liter twin-turbocharged V8.
The hybrid system allows the vehicles to be powered either exclusively by the electric motors (like the Prius) or in tandem with the gasoline unit. BMW has yet to publish any official figures, but the system is said to boost fuel-economy by around 10 to 15 percent over their conventionally-powered siblings.