Pub. Util. Code, § 1005.5

(a) Whenever the commission issues to an electrical or gas corporation a certificate authorizing the new construction of any addition to or extension of the corporation’s plant estimated to cost greater than fifty million dollars ($50,000,000), the commission shall specify in the certificate a maximum cost determined to be reasonable and prudent for the facility. The commission shall determine the maximum cost using an estimate of the anticipated construction cost, taking into consideration the design of the project, the expected duration of construction, an estimate of the effects of economic inflation, and any known engineering difficulties associated with the project.

(b) After the certificate has been issued, the corporation may apply to the commission for an increase in the maximum cost specified in the certificate. The commission may authorize an increase in the specified maximum cost if it finds and determines that the cost has in fact increased and that the present or future public convenience and necessity require construction of the project at the increased cost; otherwise, it shall deny the application.

(c) After construction has commenced, the corporation may apply to the commission for authorization to discontinue construction and recover those costs which were reasonably and prudently incurred. After a showing to the satisfaction of the commission that the present or future public convenience and necessity no longer require the completion of construction of the project, the commission may authorize discontinuance of construction and the recovery of those construction costs which were reasonable and prudent.

(d) In any decision establishing rates for an electrical or gas corporation reflecting the reasonable and prudent costs of the new construction of any addition to or extension of the corporation’s plant, when the commission has found and determined that the addition or extension is used and useful, the commission shall consider whether or not the actual costs of construction are within the maximum cost specified by the commission.