Open Access Transmission Tariff

The Open Access Transmission Tariff (Tariff or OATT) defines the terms and conditions of point-to-point and network integration transmission services, ancillary services, and generator interconnections offered by BPA Transmission Services.

BPA Tariff Effective Oct. 1, 2025

On Mar. 7, 2025, BPA issued the Administrator's Final Record of Decision in the TC-26 Terms and Conditions Tariff Proceeding adopting the modified terms and conditions of the Tariff to be effective on Oct. 1, 2025.

Open Access Transmission Tariff, effective Oct. 1, 2025
TC-26 Tariff Proceeding
 
The attachments below are included in the effective Tariff above and are also posted individually for convenience.
Attachment C (ATC Methodology) (10/1/2025)
Attachment L (LGIP) (10/1/2025)
Attachment N (SGIP) (10/1/2025)  
Attachment Q (EIM) (10/1/2025)
Attachment R (LGI Transition Process) (10/1/2025)

Reference Documents

Customer Reciprocity Statements (2/24/2012)
Attachment E: PTP Customer List (10/10/2025)
Attachment I: NT Customer List (10/10/2025)
OATT Interest Rates 

Open Access Transmission Tariff Archive

This is the archive for inactive BPA Open Access Transmission Tariffs.

Tariff adopted in TC-25 (inactive as of 9/30/2025)
Tariff adopted in TC-24 (inactive as of 6/29/2024)
Tariff adopted in TC-22 (inactive as of 9/30/2023)
Tariff adopted in TC-20 (inactive as of 9/30/2021)
2016 Open Access Transmission Tariff (inactive as of 9/30/2019)