Trade Value is a new value that's being added in the Le Guin update for non-Gestalt empires, representing the civilian and private-sector economies of these empires. All Pops generate a small amount of Trade Value based on their living standards, with higher living standard Pops generating more trade value, and is also produced by a number of different jobs such as Clerks and Merchants. Additionally, Trade Value can be found as deposits in space, representing various resources that don't have a direct industrial application but might still be desirable to your population (for a real-life example, think of things like as precious stones used in jewelry). Trade Value has no inherent purpose, but can be turned into other resources by being exploited, representing taxation and tariffs imposed on the civilian economy by an empire that has the necessary infrastructure in place to benefit from it.
In order for Trade Value to count as exploited, it has to fulfill two conditions:
1) There must be an upgraded Starbase in range from the system to collect the Trade Value. By default, upgraded Starbases can only collect inside their own system, but their collection range can be extended by constructing additional Trade Hub modules, with each module extending the collection range by a single system up to a maximum of 6 hyperlane jumps away. You do not need to build an orbital station to collect trade value from planets - this is done automatically if it is in range of a collecting Starbase.
2) Once collected, Trade Value needs to be sent to your capital system. This will be done automatically if the Starbase collecting is located in said capital system, but otherwise the Starbase must be connected to the capital through a Trade Route (more on that below).
Trade Value that is successfully exploited will be converted into other resources (currently, trade value is turned into energy credits at a 1:1 conversion rate, but which exact resources it becomes is fully scriptable and may differ depending on your empire type) and added to your monthly income.
Trade Routes are paths are that used to connect remote Starbases to your capital in order to exploit the trade value collected there. Each upgraded Starbase can support a single Trade Route by connecting to another Starbase, which is where the first Starbase will send all of its collected trade value. For example, an empire might have a remote Starbase (we'll call it starbase A), which is sending trade value to another Starbase closer to the capital (starbase B), which in turn sends on both its collected trade and all trade sent to it by starbase A on to the capital. The player has full control over which Starbase sends its value where, and can redraw routes, though there may be an efficiency loss on a newly drawn route for a time.
This means that if starbase A collects a value of 10 from the systems around it, and starbase B collects 15, 10 value will be sent from A to B and all 25 combined value is then sent on to C (the capital) and is successfully exploited. Any trade value that fails to reach the capital, either because of lack of collection, lack of a route, or piracy (more on that below) is wasted - the empire gets no benefits from it - so it'll be especially important to ensure any populous colonies that are generating a lot of trade value are properly connected via trade routes to your capital.
Trades routes will have a special map filter showing routes, protection and piracy, and is also planned to be visualized inside the systems, but more on that later.
(Ignore any weird visuals such as sector borders, it's just a bug)
Piracy and Trade Defense
Of course, all that lucrative merchandise being moved through space won't exactly go unnoticed by the less savory elements of your empire. Over time, piracy will begin to accumulate along trade routes, especially routes with a high degree of trade value moving through them. For each system with piracy that the trade route passes through, a certain amount of the trade value will be lost. To combat piracy, an empire can make use of a combination of Starbases and fleet Patrols. All upgraded Starbases will have a trade protection value, that is essentially a minimum amount of trade value that will always make it through any system under their protection, regardless of the level of piracy (representing heavily escorted merchant convoys). By default, this trade protection is only for the system they are located in, but can be extended to additional systems by building defensive modules such as Hangar Bays.
Additionally, any military fleet can be given orders to patrol a route between two Starbases to actively eliminate pirates and reduce the amount of piracy in the systems. The old system of spawning pirate ships in empty systems adjacent to your empire will also change - instead, pirate fleets may spawn in systems where a large amount of trade value is being lost to pirates. Overall, pirate fleets is something you will experience less often and can actively work to prevent, but will be more of an actual threat when they do spawn. We will most likely keep some sort of penalty for having a sprawling empire with a lot of unprotected connections, possibly by simply raising the amount of piracy experienced along your trade routes, or some sort of efficiency penalty. We may also have a system similar to the old pirates for Gestalts, since they do not have access to Trade Value or Trade Routes.
(Yes, we know the grammar/spelling is wrong, no need to point it out - the icons are also placeholders)
That's all for today! Next week we're continuing to talk about the Le Guin update, on the topic of Decisions and Planetary Bombardment
EDIT: Since it keeps being asked, at this point we are not ready to talk about how trade trades/trade agreements with other empires will work, only that they will exist in some form.