The Catalan city of Barcelona, home to Sagrada Família, is now partially powered by its own Metro underground trains, thanks to a system called regenerative braking.
When an electric vehicle is slowed, the excess kinetic energy released when pressing the brake is harvested, transformed into electricity via a generator, and then stored for future use. Larger vehicles produce more kinetic power, and have the capacity to store more excess energy. The technology is increasingly used in electric cars, but when it comes to trains, it has actually been around for decades.
Enter Barcelona's MetroCharge project, which uses brake energy from the underground trains to power those same vehicles, as well as stations and their escalators, ventilation, and lighting systems. Any excess energy is pumped up to ground level and used to power local EV charging stations.
The system, which also includes solar panels, covers the energy needs of 28 of Barcelona’s 163 subway stations, saving six percent of the total energy spent by the Metro.
The MetroCharge project cost some €7.3 million ($7.6 million), which the city expects to recover within a few of years through energy savings and revenue.
