Chinese > English Translating 真气, 真元 and 本源真气

I ran into a bit of problem. In this comic I'm working on, the MC is about to transmute his 真气 into 真元.

And the problem is I've been using "energy" to refer to both 气 and 元.

So in this comic, I've already established that 真气 is "energy." 真元 just appeared in this chapter. I can't use "energy" again for that, so what should I use.

Then I thought, "Why not nascence energy?" Because 真元, you know, is a higher form of plain ol' energy.

But then I flipped through my glossary and realized that I've already used "nascence energy" for 本源真气.

So what should I do for 真元?