Regenerative Braking

Regenerative braking is a technology used in racing cars that captures energy normally lost as heat when slowing down and converts it into electrical power that can be stored and reused to make the car go faster.

When you press the brake pedal in a regular car, friction between the brake pads and discs slows the vehicle down, and all that energy from the car's movement turns into heat that simply disappears into the air. In race cars with regenerative braking, much of that energy gets captured instead of being wasted.

Here's how it works: When the driver brakes, an electric motor attached to the car's wheels reverses its normal job. Instead of using electricity to spin the wheels, it acts like a generator, using the spinning wheels to create electricity. This process helps slow the car down while simultaneously producing electrical energy.

The electricity generated during braking is stored in a battery, flywheel, or supercapacitor. When the driver needs extra power - like when accelerating out of a corner or trying to overtake another car - they can release this stored energy back to the motor. The motor then adds extra power to the engine, giving the car a significant speed boost.

Formula 1 introduced this technology in 2009 with a system called KERS (Kinetic Energy Recovery System), which gave drivers about 80 extra horsepower for roughly seven seconds per lap. Drivers activated it by pressing a button on their steering wheel, often using it to defend their position or overtake rivals on straightaways. Today's Formula 1 cars use an even more advanced version called ERS (Energy Recovery System) that can provide up to 160 additional horsepower.

In Formula E, the all-electric racing series, regenerative braking is absolutely essential. Since these cars run entirely on battery power, recovering energy during braking helps extend how far they can race before running out of charge. The latest Formula E cars can even recover energy through the front wheels as well as the rear.

Endurance racing also benefits greatly from this technology. Long-distance races like the 24 Hours of Le Mans feature hybrid race cars that use regenerative braking to improve fuel efficiency and performance over many hours of racing. The Porsche 911 GT3R hybrid, for example, used a spinning flywheel to store recovered energy.

Beyond just providing a power boost, regenerative braking offers other advantages. It reduces wear on traditional brake components since the regenerative system does some of the work of slowing the car. This means brake pads and discs last longer and need less frequent replacement during a race weekend.

Managing regenerative braking also adds a strategic element to racing. Drivers and teams must decide when to harvest energy and when to deploy it for maximum advantage. Using the boost at the wrong time - or running out of stored energy at a crucial moment - can mean the difference between winning and losing a race.