NYISO began what is expected to be a yearlong effort of revising its Reliability Planning Process at a Transmission Planning Advisory Subcommittee meeting Jan. 20.

“This is the best opportunity, if you have more concrete feedback, especially any specific suggestions so that we can consider those as we consider revisions before we roll them out,” said Ross Altman, NYISO’s senior manager of reliability planning.

The existing process uses a single base case to determine whether the transmission system meets all reliability criteria. Base case assumptions are identified in May, finalized over the summer and voted on in fall. The final reliability need assessment is issued in late fall. This goes hand-in-hand with the Comprehensive Reliability Plan (CRP), which considers system conditions a decade into the future.

“The only specific feedback we’ve received so far to process revisions is to consider a longer horizon,” Altman said. “There was a suggestion of 15 years. We welcome folks’ thoughts on that.”

Altman said the use of base case means the ISO needs to use the most conservative assumptions to account for growing uncertainty across all elements of grid planning. (See NYISO’s 2026 to be Dominated by Reliability Concerns.) The use of a single base case when reliability margins are tight can mean “flip flopping” between having and not having a reliability need.

Several stakeholders said they were concerned with moving away from a single base case to multiple base cases or scenarios that might trigger a reliability need. Representing Multiple Intervenors, Mike Meager asked Altman to clarify how the ISO would weigh different scenarios or circumstances probabilistically.

Altman said it was difficult this early in the process for the ISO to come up with a “true stochastic” look at probabilities.

“Not declaring needs on outliers is something we’re thinking about how to accomplish,” Altman said.

He said the process must maintain that reliability needs be based on criteria, and he added that multiple combinations of system conditions could more accurately reflect the changing grid. He stressed that the ISO was committed to “open and transparent” stakeholder involvement in revising the process.

The ISO is planning to review key study assumptions for the 2026 reliability needs assessment study with a particular focus on load uncertainty, aging generation, emergency assistance and generator outage rates.

Howard Fromer of Bayonne Energy Center asked how the ISO planned to stick to a 10-year planning horizon for the CRP, given that it was planning on folding multiple forecasts into the reliability process.

“How do we prevent that flexibility you’re looking for from swamping the competitive market, which is what we designed to achieve whatever our reliability requirements are?” Fromer asked.

Altman said that was always a risk when using a decadelong planning horizon for a one-year market. He suggested that the issue be separated from short-term reliability needs planning.

Fromer replied that it deserved consideration because the ISO could force a lot of unnecessary infrastructure investment.

Another stakeholder asked whether NYISO would consider changing some of its base case inclusion rules to be more realistic rather than conservative. Meager said he agreed and wanted the ISO to seriously consider how realistic its assumptions are.

“It’s not difficult to show some reliability criteria will be violated … if there’s no bounds or restrictions or constraints on what assumptions the NYISO can pick and choose to use each year,” Meager said.

Altman replied that the ISO is indeed considering the issue.

Alex Novicki, representing Avangrid, requested that extreme weather events be accounted for in the base case because, he said, NERC was going to try to account for them in upcoming resource adequacy standards.

Meager also questioned the ISO’s timeline for potential changes.

“What you are contemplating are some of the most significant changes to the Reliability Planning Process we have ever considered, with huge impacts moving forward,” Meager said. “There’s not a lot of meat on the bones before us right now. The idea that we’d be voting on tariff changes in a couple months is incredibly ambitious, if not highly unlikely.”