Revenue and Taxation Code § 17138.1

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:

(a) A thermal system as defined in Section 25600 of the Public Resources Code.

(b) A solar system as defined in Section 25600 of the Public Resources Code.

(c) A wind energy system device that produces electricity.

(d) A fuel cell generating system, as described in the California Energy Commission’s Emerging Renewable Resources Account Guidebook, that produces electricity.