Eversource Energy and National Grid introduced asset condition projects totaling about $110 million at the ISO-NE Planning Advisory Committee meeting Jan. 27.
The proposals coincide with ISO-NE’s ongoing efforts to establish an internal asset condition reviewer. This role is intended to increase transparency into the transmission owners’ asset condition spending, which has cost the region billions in recent years. (See ISO-NE Responds to Feedback on Asset Condition Reviewer Role.)
Eversource presented a group of asset condition projects that would replace structures on six transmission lines in New Hampshire. The combined estimated costs total $101.6 million, while the expected in-service dates range from the fourth quarter of 2026 to the third quarter of 2027.
In southern New Hampshire, Eversource proposes a $32 million project on Line 367. The company would replace 97 345-kV wood structures with an average age of 55 years, along with a seven-year-old steel structure with damage from bullet holes. The estimated per-structure cost is $330,000.
Eversource’s Steve Allen noted that the company estimates the typical useful life of 115- and 345-kV natural wood structures to be 40 to 60 years.
Fifty-seven of the structures on the line require immediate replacement, while Eversource also proposes to replace the 41 other original wood structures. Replacing all original wood structures would prevent the need for an additional project “in the near future,” Allen said.
On Line A126, a 115-kV line in western New Hampshire, Eversource proposes a $7.4 million project to replace 20 wood structures with an average age of 72 years. The estimated per-structure cost is $370,000.
In southeastern New Hampshire, the company proposes to spend $38.1 million to replace 96 structures on the 115-kV A152 line. Twenty-eight of the structures need immediate replacement, while 41 structures have engineering concerns, Allen said. The average age of the wood structures is 57 years, and the estimated per-structure cost is $397,000.
Eversource proposes a $5.6 million project on the 115-kV B143 line in southern New Hampshire. The project would replace 16 wood structures at an estimated per-structure cost of $351,000. The structure ages range from 48 to 59 years.
In eastern New Hampshire, Eversource proposes a $5.5 million project on the 115-kV K174 line to replace 15 wood structures with an average age of 58 years. The company considers four of the structures to be immediate replacement needs. The estimated per-structure replacement cost is $370,000.
In central New Hampshire, the company proposes a $12.5 million project on the 115-kV M127 line. The project would replace 39 wood structures, which have an average age of 58 years, at an estimated per-structure cost of $321,000.
Allen noted that the ISO-NE 2050 Transmission Study forecasts overloads on the A152 and K174 lines, though Eversource did not identify any project modifications to address these needs. ISO-NE plans to begin stakeholder discussions about right-sizing asset condition projects in the third quarter of this year.
Eversource also presented an update on asset condition projects at two river crossings affecting several lines in Connecticut. The modifications to the design have reduced the total estimated cost by about $5.5 million. The updated combined cost estimate now totals $101.3 million.
Rafael Panos of National Grid presented a $7.3 million asset condition project to replace a pair of 61-year-old circuit breakers at a substation in Brockton, Mass. The existing breakers are deteriorating and difficult to find parts for, Panos said. The project’s estimated in-service date is May 2027.
Asset Condition Interim Review
Also at the PAC meeting, Brent Oberlin, executive director of transmission planning at ISO-NE, discussed the RTO’s interim asset condition review process. ISO-NE is working to stand up the permanent reviewer at the beginning of 2027 and is relying on an external consultant to review nine selected projects during the interim period.
The list of nine projects in the interim review is mostly unchanged from the initial list ISO-NE presented in October, though the RTO has replaced National Grid’s proposed rebuild of Line 323 in eastern Massachusetts with a different project by the company in western Massachusetts expected to cost more than $200 million. ISO-NE made the change after an outage opportunity arose for National Grid to pursue the 323 project on an earlier timeline, Oberlin said. (See ISO-NE Gives Update on Asset Condition Reviewer Role.)
ISO-NE has initiated the interim review for several projects and expects about a three-month review process for most projects on the list, he said, adding that the RTO plans to eventually present results to the PAC and “will be looking to take lessons learned and feedback on the interim process to inform the development of the permanent [asset condition] reviewer role.”
Oberlin said additional asset condition projects that are proposed in 2026 but not on the interim list will not be subject to review. Jeff Iafrati, a consultant for Customized Energy Solutions, expressed concern that this could result in TOs advancing projects for the rest of the year to avoid review.
Alex Lawton of Advanced Energy United echoed this concern, saying, “It would be more assuring if there was a bit more review for upcoming projects.”
“While it’s a possibility, I really think it’s a limited risk,” Oberlin responded.


