Cal. Pub. Util. Code § 3121

An association may engage in any activity in connection with the selling, transporting, or storing of gas which is produced and delivered to it by its members; in any activity in connection with the purchase, hiring, or use by its members of supplies, machinery, or equipment directly related to the production, transmission, storage, or marketing of gas, or in the financing of any of these activities; or in any one or more of the activities which are specified in this section.