Post-Transition Cluster Study Process

Line on Hill

This page provides information about the post-transition Cluster Study process for requests to interconnect Large Generating Facilities, governed by Attachment L to BPA's Open Access Transmission Tariff (OATT). This process will be used for all interconnection requested that are studied after the Transition Cluster Study.

Business Practices

The following business practices are applicable to the Cluster Study process. Other business practices may also apply. See all of BPA’s Transmission Business Practices.

The Cluster Request Window for the Cluster Study that will follow the Transition Cluster Study opened Jan. 27, 2025.

BPA will provide Interconnection Customers with no less than one hundred eighty (180) Calendar Days of advance notice of the start date of each Cluster Study and opening of the Cluster Request Window.

  • BPA will only accept Interconnection Requests when the Cluster Request Window is open as follows: Starting from ninety (90) Calendar Days after Transmission Provider closes the preceding Cluster Request Window and ending ninety (90) Calendar Days before the start of the next Phase One Cluster Study.

BPA encourages customers to subscribe to Tech Forum emails to receive updates on stakeholder processes, system changes, and other business-line and agency initiatives, including updates on the status of the Transition Cluster Study: Email Sign-up - Bonneville Power Administration

Submitting an Interconnection Request for a Large Generator Facility

Requirements for submitting an Interconnection Request are specified in Attachment L to BPA’s OATT (link) and applicable business practices. Requirements that may need extra attention are noted here:

  • All required forms and materials must be submitted to GI_ClusterStudies@bpa.gov
  • A completed application in the form of Appendix 1 (including applicable technical information)
  • A non-refundable $10,000 application fee (Payment and Remittance Instructions)
  • Evidence of Site Control (Site Control BP)
  • Demonstration that the site for which Interconnection Customer has Site Control is suitable for Interconnection Customer’s Generating Facility in a form reasonably acceptable to Transmission Provider, including evidence that such site is sufficient for Interconnection Customer’s Generating Facility in accordance with Good Utility Practice, and is effective through the Commercial Operation Date of the Large Generating Facility; (reference Site Control BP)
  • A Generation Model and Performance Attestation (Attachment A to Appendix 1)