Energy recovery by means of technical processes is also known as regeneration. Many SEAT cars have system for recovering braking energy.
Each time a conventional car stops, valuable energy is lost. Brake energy regeneration converts the kinetic energy released during braking (and also when coasting) into electrical energy.
This is done by means of a specially designed generator, similar to a dynamo.
The additional electrical energy obtained ensures a higher voltage, which in turn enables faster charging of the battery. This ultimately reduces fuel consumption, since the engine needs to expend less power to supply the electric generator (alternator), which in turn feeds the battery.
In addition, an intelligent battery management system ensures that at any time sufficient electrical power is available to be able to operate a start-stop system. So fuel is saved indirectly this way, too.