Cal. Rev. & Tax. Code § 40061

On or before the last day of the month following each calendar quarter, a return for the preceding quarterly period shall be filed with the board in the form as prescribed by the board, which may include, but not be limited to, electronic media.

A return shall be filed by every electric utility and by every person purchasing electrical energy, the consumption of which is subject to the surcharge and who has not paid the surcharge billed and required to be collected by an electric utility. The return shall be signed by the person required to file the return or by his or her duly authorized agent. Returns shall be authenticated in a form or pursuant to methods as may be prescribed by the board.