Formula 1 has been experimenting with Kinetic Energy Recovery System on their cars.
It was interesting watching a KERS fitted car simply drive past a Ferrari on the straight.
KERS just provides a boost during acceleration, recovering energy when slowing down or idling. It is not a full hybrid (like say the Toyota Prius).
This would suggest that a KERS would be a way of providing top end performance with mid range or diesel engines and providing the necessary boost for overtaking.
Will we see KERS in road cars in particular BMW's?