>The total amount of energy and matter in the Universe remains constant, merely changing from one form to another.
>Energy changes from one form to another
If we get a reverse dyson sphere, we could heat up an area and just create stars, using the natural processes of the Planet of Earth, to heat up the area of space we want to build a star in, and we don't need fuel, except enough energy to superheat a region of space, until darkmatter has become a star, and then we could retain the process using thermo turbines.