I still have some problems with this feature, as in I cant get it to work.
I have 2 power generators, for convenience sake i've let them both cut power to all buildings, so now both have 30 power free. The are faction buildings, but i'm both manager and operator.
I get a button to combine the power, but when clicked nothing happens, no error message or anything, tried it from both generators, but no result what so ever.
I tried it with being on the crewlist, as operator and as manager/operator in all cases no result.
It's being worked on, though. As stated in the Sim Posts, you'll just have to wait a bit before you can power up the facilities that need more than 30 power.
This sounds like a problem similar to what was happening earlier (which I'm not sure if anyone noticed), that when you tried to assign power down to 0 (eg, use all of the PG's power points), it would only let you go to 1. The page would simply reload and nothing would happen.
However, if you bugbase it, I'm sure Cam will simply love you forever and fix it ASAP!