Why is this called excess? What does this value represent?
Warning to new players: Based on comments here in the forum, it's clear that to properly build a a ship you must have excess energy output built into your design.
Energy Use Explained
ORIGINAL: Sliverine
Static energy usage is what your ship uses all the time regardless of whether its moving or fighting or dying. It starts using that amt from the moment it exits the yard.
Energy generation can come in 2 forms: either via generators which burn fuel to provide a constant steady stream or via energy collectors, which dont burn anything but have varying amounts of energy production depending on how far away the nearest energy source is. The value listed for collectors is presumably the max value of energy they can collect.
Energy excess is CONSTANT energy generation minus static energy usage. By constant it means collector energy isnt taken into account.
Additional energy ON TOP OF the static usage is required whenever you move (use engines) or when u fire weapons. Typically things which require additional energy for usage outside of whatever static energy they already use will have it listed. 'Static energy' and 'Energy usage' is not the same thing (a good example of this differentiation can be typically found on engines which usually require both static and normal usage).
There are different calculations for ship energy usage but i will only touch on the most basic aspect, that is to say, your energy produced should at all times be at least one higher (NOT equal) to the sum of:
-static energy usage &
-warp energy usage (reflected in the purple part of the graph).
Following this general rule guarantees that your ship will always warp at its full rated speed which is an important factor. If your production is lower then your sum, your warp speed will be significantly reduced depending on how much energy you are lacking.
If you want to find the minimum energy required for ships to engage in combat without running out, u have to factor in static usage, sprint usage and weapon usage. Please note that collectors dont work while the ship is moving! People only put collectors on their ships to cover static energy usage in order to save fuel costs since ships mostly (while under automation) just stone around.
For bases, it depends on whether your base is located in deep space or near something which is usually put in a system or near things which give out energy (like black holes or supernovas). Deep space bases have to rely solely on reactors to run therefore, they have to be constantly replenished with fuel and thus, have to be able to hold a reasonable amt of fuel (at least long enough for the transport ship to make one fuel trip with breaks inbetween). Bases that are near energy sources can be designed to be run on collectors alone but you have to make sure your generation is higher then your static usage since collectors have varying levels of energy collection with regards to their distance from the source.
ORIGINAL: Sliverine
... there isnt one (value displayed) as of yet that shows you everything in one simple value. You have to manually add in the engine usage and weapon usage yourself (u might even have to calculate your weapon usage since the value shown is on a per-shot basis not a per-second basis).
ORIGINAL: Shark7
You will notice that without the excess energy output, your hyperspace speed will suffer...20k seems to be the max, but without enough reactors, you won't reach it.
Important Links
- Weapon table: energy consumption/sec
- Energy production/use
- Shields have no energy cost, they are entirely self-contained systems
- Solar Collection while moving
Future Changes
ORIGINAL: elliotg
I agree that we need a better view of how your weapons energy use relates to your reactor energy output.
We'll add a line in the Weapons panel on the Design screen to show the "total weapons energy use per second". You can then relate that to your reactor energy output to better balance your designs.
ORIGINAL: Erik Rutins
Just FYI, this is one of the points coming in the 1.0.4 Beta:
- Added maximum weapons energy use to Design screen (top of Weapons panel) so that you can compare reactor power output to optimize military designs
I actually registered because I really like this game and I would love to see it improve some more. My point stands that the manual does a horrible job of explaining many things, one of which is ship design. 
