The power figure is a bit of a mess.Wait...what? How? Why?
I've had girlfriends tease less than you bro...
Initially the target was 650 "hp". Then, once they revealed the car, the engine was to have 654hp or 663PS. That is the most widely accepted and reported figure. However, some time after that they said the engine now makes 669PS (probably the 670 "hp" they are talking about). BUT, if you look at their website, it currently says 650PS (and the 615PS the T.33 was supposed to have, has now gone down to 600PS).
The reason for that is probably the ISG and the fan. The fan normally draws 8.5kW (12PS) and the IGS is capable of drawing (or supplying) 20kW (27PS). Normally you report the engine power with all the parasitic losses that come from powering pumps or alternators or whatever included, but it seems that the ISG (Integrated Starter Generator) - which they use instead of a normal starter/alternator - is not included in that. But, you still need some electrical power to power the ignition and all the electronics, and the fan, so there will be some parasitic loss. So if the engine made 669PS and then you deducted the 12PS that the fan takes and maybe another 7PS for other stuff, you would be at 650PS. However, the fan doesn't necessarily run all the time, so maybe you generally have more like 662PS.
Then, to make it a bit more complicated, the car also has a relatively large 48V battery that can power the fan and the ISG for a limited amount of time. From what they said about the weight of the battery, it's probably around 0.25kWh or something like that. That would allow you to run the fan for just under 2 minutes. In addition, you can also have the ISG draw power from the battery, which would give you additional 27PS - so around 697PS in total - for about 30 seconds.
Lastly, to make it even more complicated, the car can get a bit more power from ram air effect. Basically, the faster you go, the higher the pressure in the intake is and you can force in more air into the engine each stroke and make more power. So add that to the 697PS you can make in "Vmax mode" with the ISG running on battery and helping you, and you might be at 700PS+ at high speeds.
Well, at least that's my best guess at how that works, we still haven't been told the details.