Formula One cars in 2009 have the option of using KERS to recapture braking energy and use it for acceleration. Until now that braking energy has just been wasted as heat to the atmosphere. The teams appear to be having some difficulty developing these systems as pointed out in this posting.
Since the 2009 Formula One regulations will allow the use of these systems the cars equipped will technically be hybrid vehicles. Energy can be recovered via mechanical (flywheel) or electrical (supercapacitors) means and will be restricted to a maximum output of 60 kW (about 80 hp), which will help the cars accelerate faster. These systems basically take brake energy and add them to acceleration energy.
Hybrid powertrains are a good concept and certainly this offers the sport a means of developing technology that might find its way to the street for the benefit of the public.