The conversation during a five-hour meeting on changes to NYISO’s transmission planning processes became heated at times, as stakeholders challenged ISO officials on exactly how they will develop the possible scenarios they propose to use to determine reliability needs.
The joint meeting of the Installed Capacity Working Group and Transmission Planning Advisory Subcommittee on Feb. 26 was originally budgeted for only three hours, but it took up the entire morning and ran into the afternoon. More than 100 stakeholders joined the meeting by phone.
NYISO has argued that it needs multiple scenarios in its Reliability Planning Process and Short-Term Reliability Process to take uncertain future grid conditions into account. The ISO would identify only needs based on “significant and persistent” violations of reliability criteria across more than one scenario. This would avoid overbuilding the grid as well as prematurely identifying needs, NYISO argues. (See NYISO Seeks to Avoid ‘Flip-flopping’ in Revised Planning Process.)
The ISO is trying to roll out the changes before the next Reliability Needs Assessment, a timeline that requires submitting tariff revisions with FERC by summer.
Under the proposal, NYISO would first review its baseline assumptions and those for scenario development with the Electric System Planning Working Group. After conducting its analyses based on the group’s feedback, the ISO would review the recommended scenarios with the ESPWG and TPAS, initiating a 15-day comment period. The ISO would then issue a draft of the RNA for stakeholder feedback at two additional ESPWG/TPAS meetings.
The final draft RNA would need approval from the Operating and Management committees before going before the Board of Directors.
Chris Casey, an attorney representing the Natural Resources Defense Council, retorted that if the ISO had unlimited discretion to create scenarios, then they could be just as conservative, propagating similar problems across them. He said he did not see any guardrails to prevent this from occurring.
Stu Caplan, representing the New York Transmission Owners, asked about the timing of the meetings, saying he was concerned that there needed to be ample time for stakeholder feedback. He said this was particularly true for transmission owners because of their reliability obligations under state law.
“If there are multiple scenarios where elements from different scenarios contribute to common reliability, but if those elements are not correlated or likely to be coincident, then there’d be a need to provide feedback before the ISO is in a situation where it must rush to get the RNA to the Operating Committee,” Caplan said.
Zach Smith, vice president of system and resource planning, replied that the second feedback meeting was the time for stakeholders to issue support or opposition or comment on specific reliability scenarios.
“Only after weighing all that feedback would we finalize the RNA scenarios for use in the remaining analysis,” Smith said.
Mike Mager, a lawyer from Couch White representing large industrial customers, asked whether there would be a formal vote on the planning scenarios, echoing a request from earlier meetings. Smith said there is not one in the current proposal.
“We’re seeking to create a balance with the … comment period that serves to provide in a very clear and open and transparent matter the feedback everyone would have without taking that one extra step of having a formalized vote that may stand in the way of us conducting this process,” Smith said.
“This stakeholder feedback process is good; it’s absolutely what I expect from NYISO as a bare minimum,” Casey said. “I don’t consider it anywhere near sufficient. I am looking for methodological guardrails that bound scenario development and define and bound ‘significant and persistent.’”
According to its presentation, “in determining the influence of a trend or group of trends on potential scenarios, … NYISO will consider the likelihood that a trend or grouping of trends will occur in the study period; the diversity of scenarios; and the interdependence of the underlying assumptions of the scenarios.”
But multiple stakeholders had concerns about how NYISO develop plausible scenarios.
“On whether NYISO will consider the likelihood [of scenarios], I get that [the proposal] says ‘will,’ but the key word there is actually ‘consider,’” said Michael Lenoff, representing Earthjustice. “So yes, NYISO will consider, but it’s not bound by anything.”
Lenoff said any bounds on NYISO should be in the tariff because the ISO has already included what he called an implausible scenario in its Q3 2025 Short Term Assessment of Reliability report, in which the Champlain Hudson Power Express was assumed to miss its operation date.
“I think it should be that NYISO ‘shall not’ select a scenario as actionable unless it is reasonably plausible, or something like that,” Lenoff said.
A transmission planner with Consolidated Edison also noted the CHPE assumption as evidence of the need for binding rules on NYISO in the process.
Doreen Saia, a lawyer representing generation interests, said she was concerned about setting too many parameters in the tariff because it could create inflexibility. She said the current issues, such as large loads from data centers and political instability, would not have been predicted a decade ago. She urged the ISO to try to capture this in the manuals, which are easier to change than the tariff.
Saia also pointed out that the current process provides for stakeholder “discussion and action” at the MC and OC but that approval is not required. The ISO could produce a similar mechanism where stakeholders vote to indicate where they land on different scenarios. This would give the board a sense of how comfortable market participants were with the process, she said.
“It’s not perfect, but at least it provides a little more grounding on what can go forward,” Sai said. “At the end of the day, even the current tariff does not have a provision that allows market participants to stop an RNA in its tracks.”
Tony Abate, representing the New York Power Authority, said he wasn’t sure how productive it was to get so stuck on the wording of the tariff without considering whether the process is actually sufficient to meet reliability needs.
“We need some time to go through this,” Abate said. “The TOs are still thinking this through. There’s some serious technical considerations.”
“I just want to understand why there is seemingly more concern about … using conservative assumptions in the base case than using multiple scenarios,” Casey said. “I am lost by NYISO maintaining the base case as it is now and then creating as many scenarios as it wants with pretty unlimited discretion. Doesn’t that pose the exact problem you’re articulating?”
“That’s exactly the reason why we put in a lot of thought about how to build scenarios and how to take into account reliability needs,” said Yachi Lin, NYISO director of system planning.








