I subscribe to Dual Expansion theory of the universe's origin. Put simply, the UA is accelerating as a result of a "Big bang" of sorts.
No, I have never observed the UA. I apologize for my highly non-zetetic approach regarding this matter, but Round Earth scientists use theoretic science to the exclusion of all else, so I've allowed myself the same liberty in moderation.
Unless you have some evidence for this theory, preferably in the form of predictions made and then confirmed, you should just think of it as one possible theory, and be open to others. Certainly you shouldn't conjecture properties of the UA that you have not observed and are not necessary for the theory. Perhaps it's not solid, but weblike or possessing some other structure that would allow it to serve as a universal accelerator while still allowing portions of the earth's underside to be accessible. The point is, we don't know.
This seems like a good idea, but in UAT it's not just the Earth being pushed along - all matter in the universe is.
But as I said above, who knows what properties it might have?
I don't see how energy could be extracted from it since it's essentially just a huge moving wall pushing everything upwards by inertia.
It can't be pushing the Earth due to it's own inertia. It can't be moving by inertia at all, because in order to be a universal accelerator, it must be accelerating!