69-3-1204. Integrated least-cost plan. (1) The commission may adopt rules requiring a public utility to prepare and file a plan for meeting the requirements of its customers in the most cost-effective manner consistent with the public utility's obligation to serve. The rules may prescribe the content and the time for filing a plan.

(2) A plan must contain but is not limited to an evaluation of the full range of cost-effective means for the public utility to meet the service requirements of its Montana customers, including conservation or similar improvements in the efficiency by which services are used.

(3) The commission may adopt rules providing guidelines to be used in preparing a plan and identifying the criteria to be used in determining cost-effectiveness. The criteria may include externalities associated with the acquisition of a resource by a public utility. The rules must establish the minimum filing requirements for acceptance of a plan by the commission for further review. If a plan does not meet the minimum filing requirements, it must be returned to the public utility with a list of deficiencies. A corrected plan must be submitted within the time established by the commission.

(4) A plan filed with the commission by a utility, as defined in 75-20-104, must be provided to the department of environmental quality and the consumer counsel.