Cal. Rev. & Tax. Code § 40063

The board may prescribe the contents of returns of consumers subject to the surcharge. It may require the filing of returns by consumers in addition to those required by Section 40061 in circumstances where it finds that consumers’ liabilities are not being included in the return of an electric utility or it determines that consumer returns are necessary for the efficient administration of this part. Consumers’ returns shall cover the periods as the board may prescribe and shall be in the form as prescribed by the board, which may include, but not be limited to, electronic media. Returns shall be authenticated in a form or pursuant to methods as may be prescribed by the board.