Revised Interconnection Customer’s share of costs of the Phase One Cluster Study of the Transition Cluster

In the Transition Phase One Scoping Meeting held in March 2025, BPA shared that it was using the MW of requested Interconnection Service in the formula that determines the study deposits. BPA confirmed this treatment in the Large Generator Interconnection Transition Cluster Scoping Meeting Questions & Answers Log posted after the meeting (see question #5).

Per our communication to customers, Interconnection Service level was used in the Transition Phase One Cluster Study Agreements to determine the study deposits and fill in the formula used to allocate the costs of the Phase One Cluster Study to each customer. However, the cost allocation estimates posted on July 24, 2025, utilized the MW nameplate of the relevant generating facility in calculating each customer's estimated allocation of the costs of the Phase One Cluster Study.

BPA has recalculated the cost allocation estimates using the MW of requested Interconnection Service as reflected in the current contracts on the left navigation of OASIS and on the Generator Interconnection page under Related Links.

BPA is currently revisiting which figure should be used in the study deposits and study cost allocations for both the Transition Phase Two Cluster Study and the Durable Cluster Studies to ensure the approach aligns with the tariff. If a change is proposed, BPA will provide customer notice and will follow the appropriate process, such as the standard Business Practice change process.