For essential stewardship activities for which appropriations were provided to the Tennessee Valley Authority in Public Law 104–206, such sums as are necessary in fiscal year 1999 and thereafter, to be derived only from one or more of the following sources: nonpower fund balances and collections; investment returns of the nonpower program; applied programmatic savings in the power and nonpower programs; savings from the suspension of bonuses and awards; savings from reductions in memberships and contributions; increases in collections resulting from nonpower activities, including user fees; or increases in charges to private and public utilities both investor and cooperatively owned, as well as to direct load customers: Provided, That such funds are available to fund the stewardship activities under this section, notwithstanding sections 11, 14, 15, 29 [16 U.S.C. 831j, 831m, 831n, 831bb], or other provisions of the Tennessee Valley Authority Act [16 U.S.C. 831 et seq.], as amended, or provisions of the TVA power bond covenants: Provided further, That the savings from, and revenue adjustments to, the TVA budget in fiscal year 1999 and thereafter shall be sufficient to fund the aforementioned stewardship activities such that the net spending authority and resulting outlays for these activities shall not exceed $0 in fiscal year 1999 and thereafter.