Following its increase of the transfer limits on three interfaces in Maine, ISO-NE has increased the capacity import capability of the New Brunswick-New England (NB-NE) interface from 700 MW to 980 MW, Alex Rost of ISO-NE told its Planning Advisory Committee.
ISO-NE announced the Maine transfer limit increases to the PAC in June. (See ISO-NE PAC Briefs: June 20, 2024.) The increases were the result of changes to how the RTO calculates the limits, which now are “based solely on ‘design contingencies’ — loss of transmission lines, transformers, etc.,” ISO-NE said.
Capacity historically has been constrained in parts of Maine because of the interface transfer limits and existing capacity resources above the Maine interfaces, Rost said, adding that “the amount of capacity than can be transferred over the NB-NE interface has been limited to 700 MW out of a possible 1,000 MW for many years.”
He noted that “proposed new capacity resources north of the Orrington-South interface have been unable to qualify for FCAs [forward capacity auctions] for many years,” and new resources have faced similar problems above the Surowiec-South interface since 2016.
Responding to stakeholder questions, Rost said the import capability increase from New Brunswick likely means no new headroom will be made available for new capacity resources above these interfaces.
“I’m not going to give official overlapping impact analysis answers today, … but if you walk through the analyses and steps that we went through and you crunch the numbers, that would indicate that there is no headroom,” Rost said.
Abigail Krich of Boreas Renewables expressed concern that increasing the import capability from New Brunswick but not increasing the limits on domestic capacity could lead to the increased transfer capabilities being “reserved and underused.”
When transfer limits are increased, “we reserve those for imports, instead of for domestic generation qualified to participate in the capacity market,” Krich said. “We reserve them for imports regardless of whether they actually get used for imports. We often see that the New Brunswick interface, historically, even at 700 MW, has not been fully subscribed.
“This is something we should all be thinking about: How we can better utilize this transfer capability to ensure we’re getting the most out of it?”
Rost also noted that ISO-NE likely will reassess the internal transfer limits once the New England Clean Energy Connect transmission line is in service to account for system upgrades associated with the line.
Eversource Asset Condition Project Cost Increase
Also at the PAC, Chris Soderman of Eversource presented a cost and scope increase of an asset condition project in Connecticut. The project now includes the replacement of 22 structures and is projected to cost $32.2 million, compared to the initial estimate of $11.6 million. The project has an estimated in-service date of the fourth quarter of 2025.
