To:                  PAC Matters

From:             NESCOE (contact: Dorothy Capra)

Re:                  ISO-NE proposal for changes in Needs Assessments assumptions

Date:               June 29, 2022

This memo is in response to ISO-NE’s proposal entitled “Generator Outage and Interface Assumptions for Needs Assessments”, which was presented at the June 15, 2022 Planning Advisory Committee meeting.  ISO-NE asked for feedback by June 29, 2022. In its presentation, ISO-NE described a move away from the probabilistic planning assumptions that it has been using for several years to model generators out-of-service in needs assessments.  It appears that ISO-NE is planning to return to a methodology more closely resembling the assumption of two generators out-of-service that it used prior to adopting probabilistic methods. In addition, ISO-NE outlined changes to modeling transfers but without detail.

While NESCOE is pleased that ISO-NE is looking at possible ways to improve base case formation and modeling of transfers in transmission planning, we do not have enough information at this time to provide substantive comments.

As you recall, NESCOE was a strong proponent of probabilistic planning in base case formation. Absent more information, we are concerned the proposal may be a step backwards. We look forward to seeing the details to enable evaluation and comment.

Similarly and preliminarily, we are concerned about the proposed changes to modeling transfers and need more information.  Specifically, we are interested in learning if other control areas model transfers in the manner that ISO-NE is proposing.

We appreciate the opportunity to continue discussion about these matters.