ATC Methodology

This page contains BPA’s ATC methodologies for both the Short-term (0-13 months) and Planning (long-term) horizons and other related information. You can find tools and reports to help evaluate and analyze transmission availability here. 

Effective 10/1/2023, BPA does not calculate ATC for the for the flow-based paths (Map of Long-Term BPA Constraints) in the long-term planning time horizon (beyond 13 months through 10 years).  Commercial powerflow studies are performed to evaluate whether transmission service requests and/or Network Load and resource forecasts, impacting flow-based constraints during this time period, can be granted or require additional study to identify transmission system upgrades necessary to reliably offer transmission service.

Short-term Horizon (0 - 13 months)

ATC Implementation Document, V87

(Effective 12/04/2025)

ATC Implementation Document Version History

(Effective 12/04/2025)

TRM Implementation Document, V11

(Effective 12/04/2025)

 CBM Implementation Document

(Effective 04/14/2023)

System Operating Limits Methodology for the Operations Horizon

Map of Short-term BPA Constraints

(Effective 02/13/2024)

Data Request Form *

(Effective 12/04/2025)

 The Data Request Form is only for use by the specific entities identified in the form. Send all completed forms to with "Data Request Form" in the subject line.

Planning Horizon (beyond 13 months)

Firm Available Transfer Capability (ATCF) Methodology for the Long-Term Planning Time Horizon V19 (Effective 10/01/2023)

Map of Long-term BPA Constraints (Effective 12/15/2023)

Data Exhibit Validation Requirements - Final (Posted 09/03/2024)

Reference Documents

  • Attachment C/ATC Calculation Process Flow Diagram (Effective 10/1/2023)

Contact Information

"Please send any data-sharing requests, questions about BPA’s TTC/ATC/TRM/CBM methodologies,or general comments/questions about ATC to techforum@bpa.gov and specify the nature of your request in the subject line.

To receive emails about ATC Methodology updates and Customer Involvement meetings, select the techforum mail list check box on the sign-up form".

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