Unless I've not noticed an already existing mechanic, I feel that having over-stressed generators (i.e. youve gone into the red with your energy budget) should be a more punishing occurance. Currently, If you go into a negative balance, it is all too easy to simply pause the game and flick off some un-used units.
(this means not having a brown out, but being on any number below 0 in the power budget)
Think of it this way, If a power plant in reality is taxed beyond its intended abilities, there becomes a severe amount of diminishing return and the machinery obviously takes more wear in a shorter amount of time.
I propose one of two (or possibly both) downsides to staying inside a negative power supply:
1. If/when your generators become over taxed like that, the efficiency of your metal and crystal mining buildings could drop by a small degree.
2. (my personal favorite idea) The generator or generators which are keeping the entire power grid from going into brown out begin taking a very slow self attrition damage to simulate increased wear and tear. This could be so that it would take 10 or so minutes before an unattended, over stressed generator would fail and break as if it were destroyed by an attack. --This attrition could be dealt with easily by even just 1 engineer (or more if balance requires) yet would obviously present a slight extra strain on your resources and would tie up the attention of an engineer every once in a while.
The 10 minute attrition would allow for MORE than enough time to build some form of back up generator or to rebuild generators which were lost, thus addressing the negative balance.
There would be no more micromanagement than now as these effects would manage themselves depending on your overall power status, something that i think every player keeps a close eye on.
Tell me what you guys think. I wonder if this would still be balanced and if anyone would find it to be an interesting situation to run into.
If there are any questions or suggestions, id love to hear them.