Bonneville Power Administration Appropriations Refinancing Act

Bonneville Power Administration Appropriations Refinancing Act - Prescribes guidelines under which the Administrator of the Bonneville Power Administration (BPA) shall refinance a certain appropriated debt by determining with the approval of the Secretary of the Treasury: (1) a new principal amount for such debt; (2) a new interest rate for such debt based on the Treasury rate for the old capital investment; and (3) a $100 million limit on prepayments of old capital investments before a certain date.

Prescribes guidelines for interest rates for new capital investments.

Amends the Confederated Tribes of the Colville Reservation Grand Coulee Dam Settlement Act to appropriate specified amounts to the Administrator in certain fiscal years so long as the Administrator makes annual payments to the Tribes under a certain settlement agreement.

Directs the Administrator to offer to include provisions in future electric power service contracts that preclude further increases in the principal amount or interest rate obligations to the Government.

Directs the Administrator to study and report to the Congress on: (1) the effect that rate increases for electric power sales may have upon the BPA customer base; and (2) the total prior costs incurred and the total future costs anticipated by the BPA for compliance with the Endangered Species Act.