Concepts: Trade


Ah, trade. The blood that flows through a nation’s arteries. In Imperia, trade and the network that it occupies can make or break your empire. Every planet can not always be self-sufficient, and this is where inter-empire trade comes in. When a planet is getting low on food or materials to keep their populace happy and advancing forward, trouble can occur. Here is the explanation of the trade system and how to build it into the arteries of a strong empire.


There are two types of trades. A DOWNSTREAM trade is one that flows materials and food from planets towards the major hubs, i.e. planet —> system hub —> sector hub —> empire hub. If a planet can send excess goods and is not embargoing its own trade OR is not stockpiling, it will always send those goods to the closest available trade hub.

In contrast, an UPSTREAM trade is one where a planet requires materials or food, and thus goods are shipped back to the planet in need FROM a hub higher on the hierarchy. For instance, if a system capital was running low on food, the capital would first look to the sector capital to see if they were able to send goods, and if not, then the imperial capital. There is a very large efficiency penalty depending on receiving base size, the greed and traits of the receiving viceroy, the difference between the planet rants, and the distance the goods are shipped.


Any planet can send and receive goods once they have at least a level I Logistical Station, but only trade hubs can receive non-emergency goods from upstream entities. To be designated as a Trade Hub, a planet must:

  • be a capital
  • have at least a Level I Starbase
  • pass a Designate Planet As Trade Hub Edict

Due to the organization required, hubs can only be created at government seats, so system hubs can only be created within system capitals, and sector hubs can only be created within sector capitals. Any planet can build a starbase or logistical station, and there is no minimum level for starbases to be to have a hub, but there is a throughput maximum for each level per turn as follows:

  • LEVEL I: 5000 materials/food total can be moved in/out
  • LEVEL II: 10000 materials/food total can be moved in/out
  • LEVEL III: 20000 materials/food total can be moved in/out
  • LEVEL IV: 50000 materials/food total can be moved in/out
  • LEVEL V: 100000 materials/food total can be moved in/out

It is recommended, but not required, to have at least one starbase level more than your trade hub level to ensure ease of moving resources; i.e. a level II starbase for a system trade hub, etc. Eventually, trade technology will make these throughput levels increase per level of starbase.

Trade hubs work like this at each level:

  • SYSTEM TRADE HUBS – Collect excess food and processed materials at full efficiency from PLANETS WITHIN THAT SYSTEM WITH STARBASES OR LOGISTICAL STATIONS. 80% of collected materials are sent downstream to a SECTOR TRADE HUB if one is set up (with minor efficiency loss), while the remainder is kept by the station as a tariff to ensure efficiency and low corruption. Otherwise sent to EMPIRE TRADE HUB (your empire capital) (with high efficiency loss). If materials or food are needed by a planet in the same system (alert generated), this hub will send UPSTREAM as long as there is available material/food.
  • SECTOR TRADE HUBS – Collect excess food and processed materials from SYSTEM TRADE HUBS WITHIN THAT SECTOR if available, otherwise PLANETS WITHIN THAT SECTOR WITH STARBASES OR LOGISTICAL STATIONS (with efficiency loss). 80% of excess of collected materials are sent downstream to EMPIRE TRADE HUB. If materials or food are needed by a planet in the same sector(alert generated), AND THERE IS NOT A VALID SYSTEM TRADE HUB in that system (either does not exist or there are not enough items to send) this hub will send UPSTREAM as long as there is available material/food (with efficiency loss depending on distance, especially food)
  • EMPIRE TRADE HUB – Collect excess food and processed materials from SECTOR TRADE HUBS, or SYSTEM TRADE HUBS where there are no SECTOR TRADE HUBS. Sends replenishment cargo upstream to SECTOR TRADE HUBS, or SYSTEM TRADE HUBS if no SECTOR TRADE HUBS exist (with efficiency loss), and will send emergency materials or food to INDIVIDUAL PLANETS WITH STARBASES at a high efficiency loss if no other option exists.


Trade view on the quadrant map - green represents empire trade hub, yellow represents sector-level trade hubs, and red represents system-level trade hubs. Green lines and arrows represent DOWNSTREAM trades, while red lines and arrows represent UPSTREAM trades.

You can see at a glance how your trade network is set up by setting the trade view on the quadrant map. Systems that are inhabited and do not have a red circle will only receive emergency materials and food from their sector hub at a huge efficiency loss, and if there is no sector hub, the Empire will lend a hand, but between corruption, inefficiency in moving materials into a starbase that was not designed for it, and distance, you will lose a lot of the materials and (especially!) the food. This is why it is so critical to build a solid trade network as soon as possible – you don’t want planets with large surpluses just sitting there, unable to contribute to their sector or system network.


While you can not directly control what is moved through the network, nor will you see the freighters on the quadrant map, you can set a trade embargo on a certain planet/system/sector. Obviously, this will piss off the affected planets/systems and their respective leaders, so why in the world would you want to do this? In some cases, it may be a matter of survival of the fittest. If you have a backwater system that has a low population but is sucking up materials and food at a high rate, and you have a more, ah, politically important system that is struggling as well and your empire depots are getting low on materials, sometimes you have to declare ‘survival of the fittest’ and let the have-not systems figure it out on their own.


You can also designate a planet to stockpile goods. When a planet is stockpiling, they will no longer send goods upstream or downstream; instead, they will conserve goods for their needs. They will begin to receive upstream trades to replenish stocks for both food and materials. Be careful not to let a planet stockpile goods too long, especially if there is a large efficiency gap where you are losing a lot of goods in transit.

When you ask a planet to send goods, the upstream trades will stop, but depending on your viceroy, they may refuse to begin sending goods back through the trade network. Think carefully before you extend this privilege to a planet - make sure your viceroy will be willing to 'play ball' when you need their goods again!


So as an emperor, all you have to do is insure that you have a solid trade network in place with planets that are creating a surplus to fuel the network. Your capital planet is a production powerhouse, but it can not single-handedly sustain your entire Empire, especially if unrest rises or changes are made to the planet economy. That is where manufacturing and agriculture outposts can be very handy – they focus exclusively on the resource they are set up for and they come with a level I logistical station as part of the cost of setup!

Trade and resource production will make or break your reign as Emperor. People need food and your planets must grow with materials to survive. Sometimes, hard choices must be made for the good of the whole, and it is up to you to make those choices!

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