Can someone explain to me how production/import/export actually work? I just checked my colonies and my main planet produces 10 ore, uses 8 in refining but the tooltip says it still exports 10 units of ore?
Also, what counts as "the highest local source of supply"?
The economy is simplified.
By that I mean instead of producing x goods then consuming x goods, your industries produce and DEMAND things instead. By that I mean if you produce 6 metals, and a industry demands 6 metals, you have satisfied the demand of the industry that needed 6 metal.
For example, patrol station needs 2 heavy armaments and your heavy industry makes 2 heavy armaments; this supplies the demand of the patrol station so it works at 100 percent, but the heavy industry can ALSO ship out that 2 heavy armaments because it meets the demand of the patrol station, not the consumption. Aka the items the heavy industry makes are not CONSUMED, they are DEMANDED.
This, theoretically, means if you have a planet that makes enough products in its industry to fulfill the demand of ALL INDUSTRIES of ALL your planets, you no longer need to import, which saves costs; which also ties into the "highest local source of supply"; aka the planet you own that gives the highest level of goods that supplies your demands. If you don't have a planet that supplies enough goods to meet the demands of another planet you own, you will instead import; which reduces profits.
JDCollie does an entire video on it that explains it better here:
https://www.youtube.com/watch?v=JDnQ-ZiFyEk&t=1640s