There has already been plenty of rumor about an electric turbo so your information may very well be accurate.
It does strike me as a bit strange that you would get confirmation somehow of an electric turbo setup with three turbos, but not details of how many of each type. Color me a bit skeptical. But don't take it to heart, skepticism is a healthy component of speculative discussion.
A true cynic may even suggest that you have no source and instead started this thread in an effort to draw out the truth, or at least to spark a debate with an attempt to maximize exposure. Of course, I am not that cynical in this particular instance, so I will not assert that to be the case. On the other hand, if others were to assert something like that, I may not necessarily disagree with them either.
Hopefully we know more soon.