They all look identical so you can't tell them apart at a glance. I think it'd be great if the bases of them were the same color as assemblers, with tier 1 being greenish grey, tier 2 being blue and tier 3 being green.
You're right, the colors on the energy panels aren't great. I've updated the graphics for them - I did make tier 3 red since that is the same color as the assembling machines.
