I do have the Naval Energy unit and the normal extra at the same time
Hmmm. Are you sure about that? That shouldn't even be possible. In 1.65 it is impossible. The extra unit is replaced with the navel unit, and not purchasable again afterwards. In 1.69 you can purchase the extra unit again, but your naval unit is traded in at that moment.
But there's a bug in 1.69 that means the normal unit is for sale when you've got the extra, but not if you haven't (making it impossible to repair if you've not got the extra unit), so I don't think that really counts.
I appear to have them listed in my equipment list. How do I post a screen shot of this?
Svenson
Two steps:
First upload the screenshot to one of the free picture-hosting websites. I myself am using http://www.imageshack.us.
Then write a post. If you want the screenshot to show up in your post you have to use the Img-button. Just put the link to your screenshot between the two tags, like this:
Yes, indeed. The script of the "Thargoid Plans" mission awards you with the Naval Energy Unit without taking away the Extra Energy Unit. So as long as you stay in your current ship you will have both.
But if you trade in your ship and buy another, you will be able to install only one of them. Both can be purchased (but the NEU only on TL 14+ planets), but if you buy the other model, the first one is replaced.
(I have traded in my ship after doing the mission, but this was long ago, so I didn't remember this behaviour. Now I recall.)