Hehe, whoops! No, this is a bug of a different nature
The manual is correct, it's supposed to be 50 as it has been in all previous releases, but a change to the handling formula to incorporate a new feature you'll find later in the game overlooked something and I accidentally gave the player twice the base storage.
So until Alpha 12 everyone gets a free extra 50 energy storage! Not a huge amount anyway, so that's okay