Well if this is making $800 million dollars for the Federal Government every year I see now need as of now to privatize it unless someone can give me a convincing argument otherwise.
Instead of making $800 million next year by keeping the TVA, we can make up to $100 billion by selling it. That would wipe out a quarter of the federal budget deficit, and free up money that can be used for a variety of other programs.
Furthermore, privatization of other agencies like the TVA has been performed before, and with great success (as Supersoulty previously indicated).
Finally, in general, private individuals should be running businesses, not the government.