MODULES: Power Generator - #00026
May the juice be with you!
Power plants are the true core of a ship. At least energy wise.
They provide your ship with a certain amount of energy which must be higher than all modules you are currently actively using.
In other words: A 15 MJ power plant can provide 'juice' for 15 modules with 1 MJ each. Only an example. A dumb one. You get the point.
There are two 'flows of energy' in your ship. The one is the basic power - provided by your power generator - which is basically responsible for 'keeping the light on'.
The other 'flow of energy' is thermic power (heat) distributed (away) from modules using your power distributor.
Both 'flows' are separate. If in doubt why your weapons always shout 'thermal overload' and object to your wish for demolishing your opponent, read about the power distributor.
Sizes and Energy
Power Generators come in sizes from 1 to 8. Each size does provide more energy, if compared to the same quality (A..E) of another size. Each step from E to A in one size provides more energy. Sounds useless, read on:
Power Generators are a major factor in terms of how much your ship heats up.
When in outfitting, check for their Efficiency: The higher, the more heat your future Power Generator produces.
This is where your (future) question is answered:
Should I use a smaller A quality power plant or a larger E quality power plant? The price of the ones with a lower quality ranking is lower, by magnitudes!
As a general rule, you can say: "Aim for A" with power generators.
Here is why: an "E" rated power plant has an efficiency of 1.00 while an "A" rated power plant has an efficiency of 0.40
This is not just a number, it goes like this: For each MJ of power generated by a power plant, your ship will be heated up by 1 MJ x 1.00 = 1 heat unit using an "E" quality power generator.
Using a high quality "A" power generator, your ship only heats up with 10 MJ x 0.4 = 4 units of heat.
This doesn't sound much at first, but the effect can be devastating. Not only when you're out on an exploration trip and you can't use your fuel scoop's capabilities to a full extent because of your ship constantly overheating, but also in combat where not only your own weapons heat your ship up to critical levels depending on your weapon setup, your enemies weapons might do so, too. Add a bad location near a main star and you're in deep trouble.
If you got the money, use "A" rated power plants of a sufficient size. If not, use the nearest quality ranking. The power plant is the only module with which considering using a heavy "B" rated module is viable - if you need the power and you don't have the money for an "A" rated module.
If you need more available power on your ship, you can research Guardian technology and collect the needed stuff to unlock Guardian Hybrid Power Generators.
Guardian Power Plants offer about 30% more power than an A rated power plant of the same size with about 20% more mass. This is not a bad combination, although Guardian Power Plants are far from being cool runners. Their efficiency is 0.50 and there are no modifications available.
The other option is engineering a power plant. An easy grade 1 enhanced output modification can be done with Felicity Farseer. Higher grades need further Engineers to be unlocked and lots of material to be collected. High grade material.
What you get is a dream, though. A grade 1 overcharged power plant delivers 12% more power. On a 5A power generator with 20.40 MJ of power this is more than 22.8 MJ after this simple and easy modification. 2.4 MJ more. Think about that huge shield cell bank you can carry now... it might save your life.
Overcharged power plants have increased heat production as a side effect. Up to overcharging in grade 3, this is (most often) not really a problem, higher overcharging needs cool weapons and thrusters on some ships, less so on others. It is highly advisable to use 'thermal spread' as an experimental effect on overcharged power generators. It reduces heat creation from 0.46 to 0.41 (near original 'A' level) on a grade 3 overcharged power generator.
Keep it cool.
More about power plants in the Engineering chapter.