Cal. Pub. Util. Code § 132810

The governing board of the commission at its first meeting, and thereafter annually at the first meeting in January, shall elect a chairperson from its members who shall preside at all meetings, and a vice chairperson who shall preside in his or her absence. In the event of their absence or inability to act, the members present, by an order entered in the minutes, shall select one of their members to act as chairperson pro tempore, who, while so acting shall have all of the authority of the chairperson.