Ok, so the subject line is probably not super helpful. The premise of the book is the discovery of a separate dimension of pure energy. Reactors are created that can punch a hole between dimensions and tap the energy. Space travel through the alternate dimension is developed. You can punch a hole, step into the other dimension and travel, then come back though at a distant point in our dimension, effectively allowing FTL travel. Folks go out and colonize a planet with this tech. They lay down a power grid on the planet field by the dimension-hole reactors, and managed by helpful AI. The power grid allows all sorts of almost magical things.
Something goes wrong and the colony is cut off from home. The colonists realize that they're going to collapse into a dark age. The AI decides it's smarter than the humans anyway, and chooses to adopt the role of neutral observer, to study them.
I didn't read any of the other books, but my impression was that this was the prologue sci-fi book that led into a psuedo-fantasy series of books generations after the fall of the original colonists when their descendants had forgotten their origins. Any help is greatly appreciated. Not being able to pin down author or title of this book is driving me nuts.