"(k)    When essential to the proper administration of its corporate affairs or necessary for the proper transaction of its business or to carry out the purposes for which it was organized, to contract indebtedness and issue bonds subject to the approval of the President of the Philippines upon the recommendation of the National Economic Council. The total indebtedness of the Corporation, of all classes, shall not at any time exceed five hundred million pesos, and the issue of bonds shall be subject to the conditions set forth in section four of this Act. All projects to be financed with funds accruing from this increased indebtedness shall be approved by the National Economic Council: Provided, however, That in distributing and allocating the output produced by the National Power Corporation, the needs and requirements of the different users thereof whether for public utility, industrial or otherwise should be taken into account and a just and equitable distribution and allocation thereof should be made, giving preference to the need of the adjacent areas: And provided, further, That areas traversed by transmission lines shall be allocated electricity proportionate to the needs of the areas."