Here is the key claim
“The dump truck, at 45 tons, ascends the 13-percent grade and takes on 65 tons of ore. With more than double the weight going back down the hill, the beast’s regenerative braking system recaptures more than enough energy to refill the charge the eDumper used going up.”
so if we create a car for someone who lives on top of a hill, they could go to town downhill, using their brakes to regenerate energy, and the car would go back home without needing to recharge- basically- sounds good- starts looking for house on a hill lol