So, they should move from their planet and live around their star, in order to have energy.
This looks every minute more impracticable and inefficient to me.
Where did you get those numbers?
Honestly I thought were higher. Are they expressed in Joule or which unit of measurement?
To me it's not completely correct to confront pre-electricity civilizations and us in terms of energy consumption.
You say that It seems risky to try to place limits on what may be possible in the future, but maybe it's more risky to not place a limit on where we can go with energy demand, otherwise we're really just a virus on this Earth.