U.N. Ambassador Bill Richardson is now also officially the U.S. secretary of energy.

He was sworn in Tuesday, a day after a Senate committee chairman cleared him of allegations that he misled the panel about a job offer to Monica Lewinsky.Richardson, who officially takes over his post Monday, was sworn in mid-day at the Department of Energy. Undersecretary of Energy Ernie Moniz conducted the small, private ceremony, said Richardson's spokesman Stu Nagurka.