It's not surprising that the most commonly used rigs are energy grid ones in the game
Commonly Used Rigs - In EVE, capacitor is life. It's not surprising that the most commonly used Tera Gold rigs are energy grid ones.
The single most used rig is the Capacitor Control Circuit, the Tech I variant of which provides a solid 15% boost to your ship's capacitor recharge rate for a measly 100 calibration and no drawbacks.
That makes them as effective as a Tech I capacitor recharger, so it's not uncommon for people to slap three of these tasty treats onto their ships.
Fitting some Capacitor Control Circuits will often free up valuable mid slots normally used for capacitor generation. Mid slots being arguably the most useful slot, used for shield modules, electronic warfare, sensor boosters, microwarpdrives and afterburners, it's not surprising that people would Endeavour to free them up using rigs.
Another popular rig is the Ancillary Current Router, a rig whose Tech I variant boosts your ship's power grid output by a pleasing 10% for the same 100 calibration as the capacitor rig, again with no drawbacks.
This is equivalent to a Tech I reactor control unit and could free up low slots you might need for amour tanking or modules to help you deal more damage.
