Gross income does not include any amount received as a rebate, voucher, or other financial incentive issued by the California Energy Commission, the Public Utility Commission, or a local publicly owned electric utility, as defined in subdivision (d) of Section 9604 of the Public Utilities Code, for any expenses paid or incurred by a taxpayer for the purchase or installation of any of the following devices:
Ca. Rev. and Tax. Code § 17138.1