Help needed with Energy/Economic Resource in Space Empire Game

When does one resource replace another?

If it serves multiple uses like you have.
Just like money.
However, if something is wanted by a lot of buyers. The price increases.
Since it is not simple to implement inflation in a board game. How about simply needing 2 gold for 1 ore, or 2 gold for 1 research.
Gold will keep its multiple use and might be a helping hand, there where needed. But gold alone will not get the players where they want to be.

Another way of having gold AND ore and research. Is needing 1 gold to spend 1 ore, and 1 gold to spend 1 research. Meaning that if you build a ship of 3 ore. The game now asks for 3 ore and 3 gold. You even can play a bit with these numbers, 2 gold and 4 ore or 4 gold and 2 ore. Depending on the ship that the player wants to build.

I ask this question, most notably because in game design you typically remove those things that end-up not working as elegantly as you desire. For instance, Eclipse's use of three resources makes sense because each one performs in a fundamentally different way. In TI3, the use of Trade Goods as a "wild card" makes perfect sense, because other than a few Action cards and the Trade Strategy card, you can't actively produce more of them, while the conquered planets actually provide you the main resources of the game...money and influence.

Having simply Ore and Research/Science makes perfect sense, and depending on where you are in the design plan, you may want to simply play-test what you have and determine if there's anything really missing. From my own experience, we maintained only two resources in our game, TAU CETI, Energy (which is expended when performing most Actions) and TAU (which is spent on specific economic-related Actions). We abstracted logistical fleets and other aspects, as we didn't want to clog the board with more plastic miniatures, nor did we want the players focused on those things extraneous to the main game.

That said, may I ask, beyond the struggle for a possible third resource, what's the special niche that your game fills that I, as a player, can't find in the nearly half-dozen well-received 4X games, as that may shed some light on the possible resource as well.

Cheers,
Joe

Why not make your resources completely dependent on each other?

Like this: Mining Ore can be sold to get Gold, which can be spent for Research, which is used to get more Ore.

You can adjust the values to make it interesting, Say Ore is easy to get, but your machines will wear out and require constant Research to keep them going. You can get a fair amount of Gold for the Ore and you can trade it quickly, but traders won't give you the same amount every time; you have to sell at the right time. With the Gold you can upgrade/repair your machines using Research, but it costs a lot of Gold.

So in essence you're forcing your players to build an engine.

Anyways, just an idea.

Yes, I'm familiar with the idea, as our published game is the first cooperative 4X game (not mission-driven, see Centauri Saga) with a space theme. In TAU CETI, each of the races attempt to garner Galactic Points, upgrade their Command Ships, increase their economic well being, and build Orbitals, all the while trying to prevent or resolve (read eXterminate) planetary crises.

The idea of thwarting an external threat, makes it exceptionally appealing as a co-op game.