The Sun will eventually burn through all of its fuel and "die".... this won't happen for ~5 billion years, so we won't be around to witness this death. First the Sun will turn into a "red giant", swelling and engulfing the inner planets, before it collapses into a "white dwarf". During its white dwarf stage, it will cool and become very faint compared to the Sun as it is now. So, yes- the Sun will eventually lose all of its energy (and thus light), but it will happen after the red giant stage..... we will certainly not be around to see it!

Holly