F1 energy recovery system gathers a huge amount not a small amount. KERS (the old system) gave 80 bhp for 6 seconds. The new system gives 160 bhp, 120 bhp from braking and the rest from exhaust heat recovery.
I remember reading a book, many years ago, about the Ford GT40's at Le Mans. At the end of the Mulsanne Straight their brake discs went from -10ºC to 1000ºC, every lap!