(a) So long as the commission has not modified or revoked the certificate for an electric plant under Code Section 46-3A-6 and to the extent the utility seeks to add to its rate base upon completion of the plant construction costs that do not exceed 100 percent of those approved by the commission under Code Section 46-3A-5, Code Section 46-3A-6, or subsection (b) of this Code section, that construction cost amount may be excluded from the rate base only on the basis of fraud, concealment, failure to disclose a material fact, imprudence, or criminal misconduct. Inclusion of costs in excess of 100 percent of those approved by the commission shall not be permitted unless shown by the utility to have been reasonable and prudent.

(b) In addition to the review of the continuing need for an electric plant under construction prescribed in Code Section 46-3A-6, the commission, upon its own motion, may conduct or the utility may request that the commission conduct an ongoing review of such construction as it proceeds. Every one to three years, or at such lesser intervals upon the direction of the commission or request of the utility, the applicant shall file a progress report and any proposed revisions in the cost estimates, construction schedule, or project configuration. Within 180 days of such filing, the commission shall verify and approve or disapprove expenditures made pursuant to the certificate and shall approve, disapprove, or modify any proposed revisions. If the commission fails to so act within 180 days after such filing, the previous expenditures and any proposed revisions shall be deemed approved by operation of law.

(c) If the commission verifies expenditures as made pursuant to a certificated capacity resource, that verification forecloses subsequent exclusion of those costs from the utility's rate base, absent fraud, concealment, failure to disclose a material fact, imprudence, or criminal misconduct.

(d) If the commission disapproves of all or part of the proposed revisions and the utility cancels construction of some or all of the facility as a result of the disapproval, the utility may recover through any rate-making vehicle over a reasonable period of time, absent fraud, concealment, failure to disclose a material fact, imprudence, or criminal misconduct, the amount of its actual investment, net of actual salvage value, in the partially completed portion of the facility along with the cost of carrying the unamortized balance of that investment to the extent such investment is verified as made pursuant to the certificate.