Setting off with just 60% of the power needed to finish the race, drivers at the Formula E World Championship race in London last month relied on their brakes at tight turns to produce enough energy to complete the race's 39 laps.
The latest model of the electric race car regenerates nearly half of its power from braking in what the FIA, the global governing body of motor sports, described as the most efficient Formula E car yet.
Since its first championship in 2014, Formula E has helped hasten the development of technology for electric vehicles (EVs), making them easier to sell to consumers.