Before any agreement made pursuant to section 70-1502 or amendment to such agreement shall become effective, it shall be submitted to and approved by the Nebraska Power Review Board. When requested to approve such agreement or amendment, the Nebraska Power Review Board shall determine whether such agreement or amendment is in furtherance of the public policy of this state as set forth in section 70-1501. The board may make such investigation as it determines is necessary, give ten days’ notice by mail to such alternate power suppliers as it deems affected by the agreement or amendment, and hold a hearing if it determines one to be desirable. At the conclusion of its investigation, the Nebraska Power Review Board shall approve the agreement or amendment unless it determines that the agreement or amendment cannot be reasonably expected to fulfill the purposes of sections 70-1501 to 70-1505. The purpose of this section is to promote and encourage the making of agreements pursuant to section 70-1502.