Hi Pia, thanks for registering your thoughts with this. There has been a lot of discussion about this, and this was what was decided on by a number of the players. I'm definitely interested in hearing what everyone thinks now that they see it in practice. If a lot of players hate it, then I'll change it.
Spreading your reactors across multiple planets is not meant to cause extra strategic decisions, but rather another defense point. On the higher difficulties (or raider AI types), the AI is quite good at slipping wormhole defenses, and well-timed strikes against these energy reactors can bring down all your force fields, turrets, tractor beams, etc.
Basically, it was far too easy for the players to previously just build all of their reactors on one highly-defended planet before, which led to perfect protection unless the game was actively being lost. This meant that the only way to really have the energy balance go negative was through the overuse of parasites or something similar. This new method of handling it is not super different overall, I don't think, but it creates many more potential chinks in the players' armor, which can lead to some interesting gameplay situations. That's the goal, anyway!