I'm ok with the principle of having to place the energy generator near turrets, but it creates a whole lot of issues. The generator needs to be stronger than the turrents (or at least on the same level), else it's easier to shoot the turrets. Then, there is the issue of stacking... the "safer" way to build would be to have all turrets at the same side. So the AI basically would need something in the like of AOE siege weapons as a counter and incentive to spread out defenses. It's certainly possible with a bit of tuning.
Other (not exclusive) idea:
One possibility would be to rework the metal generators energy giving bonus to achieve brownouts. What if every "safe" (few to no enemies, linked only to allies) planet you have enabled you to remotely power-up one "additional" generator ? The metal cost could stay, to pay for the transfer.
Example: the player has 5 planets, 3 of which are safe, with either command station or command station + "free" energy gen. If you want more energy in your chokepoint, you can build up to 3 "energy booster building" (names don't matter), and you can build 3 energy emitters on your safe worlds (which could be destroyed should the planet become unsafe).
That way, if the energy booster is destroyed => brownout on the defensive planet.
If the safe planet is not safe anymore, then each "energy booster building" alternatively gets down-timed, more or less randomly, on each planet that has them, causing brown-outs there. So if your backside is hurt, your chokepoint falls (which I see as an opportunity for the AI to do something else than just hit the commands station everywhere).
Important last point: to reduce micro (because possibly one would be encouraged to build / destroy the boosters to manage energy by oneself), no links from one "safe planet" to the "energy booster building" is done by the player or anything. Only total quantity counts on both side. Second point to reduce micro, links take 10 minutes to stabilize after a destruction / construction. Which means that if, in the example above, one of the safe world loses its energy emitter, brownouts occur for 10 minutes even if the total energy quantity is reduced.