I did some calculations of the energy recovey during the race.
The maximum energy recovery per lap is 8.5MJ in the latest regulations, with the option of increasing it to 9MJ for longer tracks and decreasing it to 8MJ on shorter tracks.
I have assumed that races with over 65 laps have only 8MJ per lap, and those with under 50 have 9MJ per lap, all the rest have 8.5MJ/lap.
For comparison to the fuel energy, I have assumed 90kg race fuel, as mentioned by others above, and did it for both the maximum fuel density (41MJ/kg) and minimum fuel density (38MJ/kg).
The race energy recovery for the tracks of the 2025 season was 13.6% for fuel with the maximum fuel density, and 14.7% for fuel with the minimum fuel density.
Monaco had the most possible energy recovered with 624MJ (16.9%/18.2%) and Spa the least at 396MJ (10.7%/11.6%).
The fastest race tracks on the calendar tend to be the ones with the least amount of energy recovered over the race distance.
I am not sure which tracks are the most power sensitive - ie the ones where extra power makes the biggest difference.
That woudl be an interesting comparison to the amount of energy that can be recovered/deployed from the MGUK.