I know there is flux and it's a limiter for energy. But what bugs me is that, there is little thought behind ship customization in terms of what weapons you put on it. As long as flux is fine its golden. You can put 5 phase lances or other similar burst weapons and do massive bursts of damage in relatively small ships.
And as a Sci-Fi fan, usually lots of ship limitations comes from maximum energy the ship engines can provide. You destroyer might have 5 medium energy slots, doesn't mean that your ship power source can supply energy to 5 most hungry energy weapons.
So if you do strap 5 mining blasters, you maybe are able to shoot 3 per second because it will stress the ships power capabilities to the max. And you need to shoot them in alternate mode instead.
Or even Paragon, when firing 4 Tachyon Lances could strain his power generation to maximum and for a duration of the of the burst, the ships other weapon systems simply stop. (Energy PDs and mediums). So if you strap phase lances on your paragon medium slots, you need to fire them separately from Tachyon lances with slight delay.
Older tech ships then could be given then the ability to strap energy weapons, but they simply cannot use biggest baddest weapon for the size (Even medium like Mining blaster), because low tech ships simply doesn't have the engine power to feed it.
This could allow ships to have more mixed weapon types for more customization and still be balanced and pushed towards ballistic/missile based for low/medium tech... The result would've been more customization for ship building and more options for multi weapon choice types probably beams and pulses, but not be able to put on phase lances or blasters to a ships that cannot power it... The weapon simply gets overloaded instead. And if you truly want to have dominator with Large laser weapon slots and shoot it, you need to add extra power generator hull mod to be able to power only one tachyion lance, and if you strap two of them then you can only do it in alternating fire mode with slight delay between the lances while your PD's are offline unable to get any power to work.
The same issue is actually very prevalent to real world naval ships. Most ships that are being decommissioned is, because their power sources simply cannot power modern Radar systems that have been strapped on them...