I love the idea of this mod, it lets me have an excuse to use even more trains! However, I did some testing before I add it to my world and I have some suggestions:
1. Could you add an option to make the Power Crystals unable to be damaged by aliens, or maybe take no damage at all (but can be slowly mined to remove without returning any items)
2. Setting(s) in the mod settings to customize their spawning frequency/distance. They seem to spawn too often, and some players may want to adjust the rarity/distance between them to their own liking :)

Also, it seems the purple crystal gives more energy cost and more pollution rather than less, you may want to check that out. I look forward to adding this mod to my world! :D

Hi! Glad that you like it! The purple crystal is meant to have negative effects by design, so the idea is that you would try to avoid areas affected by it. However, I can make the purple crystal generation optional in the mod settings (but turned on by default, I think it is fun to have some slight penalties!)

1. Initially, I wanted to do it exactly as you said, but I just simply did not know how (the problem is that the crystals are spawned on the same team as the players, which is targeted by biters by default). I am still looking into how to solve it. Another solution I thought about was to make the crystals "untargetable" completely. But then you wouldn't even be able to hover over it and read about the effects of each crystal. So, also suboptimal. In short, still thinking how to get this done.

2. Can do! I have designed the spawn probability with this distribution in mind: 35% of the map area is covered by "good" (red/green/blue) crystals, 25% is covered by "bad" (purple) crystals, and the remaining 40% is not covered by anything.

The second request is quite easy to add, but I will probably be blocked by the complexity of the first one.

I released v0.0.2 with the proposed changes. Now you can turn on/off purple (negative) crystals, and also you can set the frequency of the crystal spawns.

As of the request #1, I have found how to make the crystals fully indestructible, but this means that even the players are not able to attack/damage them at all. Hopefully, they shouldn't get in the way too much, but this also means that now there is no way to destroy them (before you could, but it would take quite a lot of grenades).

I have added icon tints to crystal modules as well.

Hope this makes it good enough to be added into the save!

Perhaps looking at cliffs and cliff explosives would give insight into the desired behavior?

Thanks for the customization feature!!

That's a great idea! Cliff explosives don't do much other than, well, remove cliffs. If you could find a way to make them be used to remove unwanted crystals and/or make the crystals invincible to enemies by making them un-damageable like cliffs somehow, that would be amazing! I'm playing on a world with rampant (I'm in a bit over my head) so the crystals would get attacked and destroyed within a few minutes.

As for the purple crystals, I was mistaken, I thought they were supposed to be less crafting speed, less pollution, and less energy consumption; making machines slower but more efficient and clean (for mods that add really dirty and power-hungry machines). But I do like the idea of allowing them to be toggleable or even if they can be destroyed (say if it spawns on an ore patch or an undesirable location).

I have some thoughts that may give you ideas to do with the indestructible problem, although I don't know anything about modding so this may not help. The "Abandoned Ruins" mod (by tgnthump) has blocks that spawn as a neutral team, though that may tie in with what you said earlier about not being able to hover over the crystals for info. Then there are mods that make large power lines and rails invincible, they can still be mined by the player, maybe you could find a way to make it take a long time to mine (to ensure no misclicks), but it doesn't drop an item, so players can't relocate the crystals. It does seem like you've already thought of these two points, but anything might help spark an idea.