I hope this start of a thread will be an argument between two sides
Side number 1, in order to have expansion there has to be energy, therefore creating endless energy.
Side number 2, the expansion of empty space would not require anything in order to expand.
And one last question that I think is interesting, Suppose you have a rubber ball close to the border of the universe, if you somehow teleported the ball outside the border, then would more space be created in the universe? I think this leads to the possibility to no end to the universe, because if there was a border then it would be constantly broken by space rocks exiting the universe.