Delay in Large Generator Interconnection Phase One Cluster Re-Study Decision

Delay in Determination of Restudy

BPA is providing advance notice that there will be a delay in its decision regarding the potential for a Cluster Re-Study of the Large Generator Interconnection Phase One Cluster Study and in providing updated Phase One Cluster Study reports if a re-study is determined unnecessary. Due to the complexities involved in evaluating the impacts of withdrawals and the volume of redemonstrations received at the close of the Customer Review Period, additional time is required to make a thorough assessment and allow time for customers to cure for any deficiencies and for BPA to review. BPA anticipates deciding whether to conduct a Cluster Re-Study by July 14.

As outlined in BPA’s Open Access Transmission Tariff (OATT), Attachment L, Section 6.7(b) if one or more Interconnection Customers withdraw from a Cluster, BPA has thirty Business Days following the close of the Customer Review Period to decide whether a Cluster Re-Study is required. Under the OATT timelines, this decision would be made by June 12.

Out of 167 requests that participated in the Phase One Cluster Study, BPA received 138 redemonstrations, with over 80% of them arriving on the last two days of the Customer Review Period. After BPA completes its review of redemonstrations and sends notice of any deficiencies, customers have 15 Business Days to cure. BPA is progressing through the validation of the submitted redemonstrations but expects to still be reviewing materials submitted to cure deficiencies on June 12. BPA cannot make a determination regarding a Cluster Re-Study until this process is complete and it knows which projects will be withdrawn and which will proceed to Phase 2.

Additional Time Needed to Update Phase One Cluster Study Reports

If BPA determines no Phase One Cluster Re-Study is needed, the OATT allows an additional 30 Calendar Days to provide notice of that, as well as providing updated Phase One Cluster Study reports. BPA anticipates it will need an additional 30 Calendar Days (for a total of 60) to fully revise all Phase One Cluster Study reports, due to the number and complexity of the reports. If no Cluster Re-Study is needed, BPA will provide notice of this decision and provide updated reports on Sept. 11.

Timeline Update

Below is an updated process timeline adjusted for the delay.

Schedule if BPA determines no Cluster Re-Study is necessary

  • July 14, 2026 – BPA determines that a Cluster Re-Study is not required
  • Sept. 11, 2026 – BPA issues updated Phase One Cluster Study reports and notifies customers of determination to not Re-Study
  • Sept. 18, 2026 – Transition Process Phase Two Cluster Study Agreements tendered
  • Oct. 9, 2026 – Last day for Interconnection Customers to execute Transition Process Phase Two Cluster Study Agreements

Schedule if BPA determines a Cluster Re-Study is necessary

  • July 14, 2026 – BPA determines that a Cluster Re-Study of the Phase One Cluster Study is required. BPA notifies customers that Re-Study is required, and Phase One Cluster Re-Study begins