So there are a few components interesting in the Porsche 918's braking system that I'll speak to. 1) The brakes slow the car down through a combination of elec

So there are a few components interesting in the Porsche 918's braking system that I'll speak to. 1) The brakes slow the car down through a combination of electric generation and traditional brake pads, just like the hybrids you're familiar with. Unlike the Prius, the brakes escalate in a predictable a familiar fashion. Most regenerative braking systems do not scrub speed from the car in the same linear fashion as the 918. This is a major accomplishment because it makes the transition from regular brakes to regenerative brakes seamless and allows for spirited driving. 2) The batteries are not designed to store a substantial amount of charge, instead they are designed to provide a large chunk of the acceleration power that would normally come from a gasoline engine in a hybrid. Instead of designing the car to utilize batteries for long-ranges, Porsche designed the car to utilize batteries for sprints. 3) The net result is a car that is as spirited as a traditional sports car but with greatly increased efficiency. People that wont buy a Prius or BMW Hybrid right now because of the ride quality issues would be willing to purchase a car with the 918 style system. The school of thought behind the Prius to squeeze every drop of efficiency out of the electric side, the school of thought behind the 918 is to support spirited driving with the electric side. Both lead to increases in efficiency but only the latter is something people that consider themselves 'drivers' would buy. You can see this with Turbochargers as they are just now starting to trickle onto sport vehicles such as the BMW M4 and Ferrari has acknowledged that they will be pursuing the technology in their road cars in the near future.