Smallville :

Perry White (guest star Michael McKean), a once-promising journalist whose career was destroyed by Lionel Luthor, arrives in Smallville in search of alien stories for a tabloid news show. Although he is constantly inebriated, Perry believes he has witnessed Clark using his extraordinary speed, so he devises a dangerous scheme to expose Clark's superpowers.

Meanwhile, Lex learns that Perry has powerful incriminating evidence of Lionel's past wrongdoings. And Clark discovers his abilities are derived from the Sun, when an increase in solar flares cause his powers to either flare up, or give out completely.