This year sees the introduction of hybrid vehicles for the first time in F1, and although the technology isn't mandatory in 2009, the majority of teams have spent millions of Euros designing, manufacturing and developing their own systems.
The FIA have stipulated that teams can use either a battery or flywheel based system, and only Williams have opted to use the latter (Honda had designed it's own flywheel system but has subsequently pulled out of F1).
The idea is that the car stores the energy generated from braking, and then uses it as a power boost once per lap, the system will generate approximately 82bhp extra. This will hopefully increase overtaking and along with the new aerodynamic regulations, make the racing closer and more exciting.
However the systems are heavy, weighing around 30kgs which means the engineers have less ballast to balance the car with, so the cars can go faster in a straight line, but will go slower in the corners. And in any form of motor racing, in order to overtake first you must get close to the car in front, and if you're slower in the corners and heavier then it's highly unlikely.
So lets say that all the cars are equipped with KERS, will it make for more exciting racing? My answer is simple, no. They had a 'push-to-pass' system in Champ Car which gave the driver a boost at any time when he pressed a button on the steering wheel, they had 60 seconds of boost per-race. Unfortunately the drivers used the systems to get faster lap times rather than to overtake and most fans couldn't see the benefit. A1 GP has a similar system, and again the drivers use it to increase lap times, or when they are about to be overtaken, they use it themselves and effectively cancel out each others advantage.
I am looking forward to this weekends race to see how the KERS cars compare to the others in race conditions, and how silly the OWG will look when they realise that they've made teams spend millions of Euros, and a non-KERS car wins the race.