To be more specific, the energy should be used at the start of the acceleration phase on the straight. In order to set quicker lap times, it is crucial to produce strong bursts indeed.
“We have a set quantity of energy at our disposal, which we will use on the circuit segments where the driver opens the throttle,” Renault’s engine technical director Rémi Taffin recently told F1i. “A mathematical analysis shows that you need maximum energy at the start of the acceleration phase so you can reach the highest speed as fast as possible.
“Therefore, we supply the driver with a lot of energy for the initial burst, even if this results in a small loss thereafter. That’s why, when we look to manage the energy efficiently, the driver is asked to lift and coast or we decide to cut the MGU-K at the end of the straight.”
This means that when the driver is flat-out, the maximum power of 120kW is deployed (the engine then needs to have enough oomph to sustain that level of performance over the entire period).