ISO-NE planners will update the base cases for the Boston 2028 Needs Assessment to include Central Maine Power’s New England Clean Energy Connect (NECEC) and the Revolution and Vineyard offshore wind projects, senior engineer for transmission planning Pradip Vijayan told the Planning Advisory Committee on Thursday.

NECEC will be modeled as a 1,090-MW injection at the Larrabee Road 345-kV line in Maine, while Revolution Wind will be modeled as a 120-MW injection at the Davisville 115-kV line in Rhode Island (20% of the contact value of 600 MW). Vineyard Wind is also modeled at 20% of its contract value, or 160 MW. Revolution Wind is being included even though its impact on the Boston study area is not considered significant, Vijayan said.

The update also will reflect Forward Capacity Auction 14 retirement and permanent delist bids and FCA 13 retirement and delist bids outside Boston, resources which were assumed to be available for dispatch in the previous assessment. Additional active demand capacity resources will reduce net load by 55 MW.

The update will be restricted to an evaluation of 2028 peak load conditions; the changes are not expected to impact assessments of minimum load, short circuits or the 2022 peak load.

The RTO plans to issue its first request for proposals for a competitively developed transmission solution under FERC Order 1000 in December to address the non-time-sensitive needs identified in the assessment: a reactive device to maintain the ability to restore downtown Boston’s transmission system after Mystic Units 8 and 9 retire. (See ISO-NE Refines Competitive Tx RFP Template.)

ISO-NE planners want to maintain as much as possible of the current restoration plan, in which Mystic 8 and 9 are among the first units brought online to energize the Boston transmission system. The units help regulate system voltage during the energization of the cables. To replace them, the RTO will be seeking a dynamic reactive device capable of absorbing the charging associated with the cables, Vijayan said.

The device must be able to be re-energized remotely and adjust its voltage control set point remotely based on ISO-NE dispatch instructions. To meet NERC standard PRC-024-2 and ISO-NE’s transient voltage criteria, it also will be required to stay connected on a low-voltage ride-through for between 0.15 and 10 seconds, depending on voltage. Required high-voltage ride-through will be 0.2 to one second.

The RTO has identified several potential locations for the device: Mystic 345-kV or 115-kV; North Cambridge 345-kV or 115-kV; Wakefield Junction 345-kV or 115-kV; Woburn 345-kV or 115-kV; and Tewksbury 345-kV.

ISO-NE is also working with Eversource Energy and National Grid to develop solutions to the time-sensitive high-voltage needs identified at minimum load levels in the Needs Assessment.

They have narrowed the potential solutions to a single 160-MVAR reactor at Golden Hills 345-kV or one 76-MVAR reactor at each location for one of the following combinations:

• Everett 115-kV and K Street 115-kV
• Everett 115-kV and Lexington 115-kV
• K Street 115-kV and Lexington 115-kV

Cost estimates and evaluations of the options will be discussed at September’s PAC meeting, when a preferred alternative will be selected. The PAC will discuss the results of the Needs Assessment update in October.

Stakeholder comments on the PAC presentation should be submitted to pacmatters@iso-ne.com by Aug. 25. The RTO set the same deadline to be informed of projects that should be reflected in the assessment update because of state-sponsored solicitations.

RSP 19 Stakeholder Comment Review

ISO-NE’s Director of Resource Adequacy and System Planning, Carissa Sedlacek, presented a review of stakeholder comments on the draft 2019 Regional System Plan (RSP).

Sedlacek went one by one through 83 comments, explaining why RTO staff did or did not accept suggested edits. Some comments were legalistic tweaks to the wording, such as deleting a reference to “regional regulators,” as there is no such thing.

In several instances, the RTO preferred the phrases “energy constraint” to “fuel constraint,” and “energy storage” rather than “battery storage.”

“ISO-NE is trying to be more generic in the language, for the region has large pumped hydro facilities that are storage facilities,” Sedlacek said.

Regarding a question on exactly what the RTO meant by “variable energy resources” (VERs), she said “the sentence states that ‘VERs … are replacing nuclear, coal and oil resources…’ which is true. The [RTO] is not stating that VERs are the same as gas-fired generation, just that VERS are variable.”

Synapse Energy, commenting on behalf of the Maine Office of Public Advocate and the energy-buying consortium PowerOptions, suggested ISO-NE add a mention to 1,381 MW of storage in a section that described the region’s wind and large-scale PV resources and that it specify whether the storage is behind-the-meter, front-of-the-meter or both.

Sedlacek referred to the RTO’s comment that it considers all behind-the-meter resources in its peak and energy forecasts. “However, we don’t create a BTM energy storage forecast,” she said.

David Ismay of the Conservation Law Foundation (CLF) wanted wording changed to reflect that “five of the six” New England states have climate change as a top priority. But Sedlacek said staff did not accept that suggestion because the RSP “is not intended to be a breakout of state policies.”

CLF also recommended discussing “the connection to ISO-NE’s fuel and energy security concerns, including capacity supply obligations granted to fuel-insecure plants at effectively their full nameplate capacity.” CLF said it was “particularly relevant” given FCA 13’s clearing of NTE Energy’s Killingly Energy Center, a 650-MW natural gas generator planned in Killingly, Conn.

“The RSP is not the place to have a discussion of matters in an open docket,” Sedlacek said. “ISO-NE awaits responses from FERC on open dockets for FCA 13 and Mystic 8 and 9.

“We hear you; we see your comments. We’re talking about energy security versus fuel security, and the integration of increasing amounts of renewable resources,” she said.

2019 Economic Studies Detailed Assumptions

Stakeholders discussed the detailed assumptions for three 2019 economic studies, as presented by ISO-NE staffers Peter Wong and Patrick Boughan.

The RTO agreed to analyze scenarios and market impacts for the integration of up to 9,700 MW of offshore wind by 2035, similar to what was requested separately by the New England States Committee on Electricity and transmission developer Anbaric Development Partners. (See ISO-NE Planning Advisory Committee Briefs: April 25, 2019.)

The NESCOE scenarios will model five levels of offshore wind ranging from 1,000 to 7,000 MW, while the Anbaric scenarios will model three between 5,700 and 9,700 MW. They also will look at varying injection locations and several potential transmission expansions, most of them 345-kV reinforcements, Wong said.

In addition, planners will evaluate two potential transmission upgrades that would increase the operating limits of the Orrington South interface in Maine, as requested by RENEW Northeast.

In one scenario, planners will consider increases of 0 to 170 MW from the modified 2016 transfer limits provided by RENEW. In the second scenario, they will evaluate increases of 100 to 825 MW. The analysis will be performed with and without the interfaces downstream of Orrington South being modeled at the projected 2025 transfer limits.

Based on the currently expected transmission system for 2030, the RTO anticipates it could add about 7,000 MW of offshore wind without additional major 345-kV reinforcements, though some reinforcement or expansion may still be needed, Wong said.

If more than 7,000 MW is added, the RTO sees the potential need for transmission reinforcements or new injections.

NESCOE counsel and analyst Ben D’Antonio asked how ISO-NE ranked the alternative transmission upgrades or reinforcements to accommodate offshore wind. Wong said that the RTO would discuss the issue and report back.

“If there’s more reinforcements beyond 345-kV lines, we want to see that,” D’Antonio said.

“We will be developing plans and high-level expansion costs associated with those needs,” Wong said.

Theodore Paradise, counsel and senior vice president of transmission strategy at Anbaric, said, “When we get close, is it that 200 MW that really pushes it over [the transmission capacity limit]? … If we spread out these interconnection points so we don’t overload, we’re OK with that too.”

“We will have to decide what modeling to use for best results,” Wong said.

VELCO Berlin Substation Condition

Vermont Electric Power Co. (VELCO) engineer Hantz Presume reported on the dilapidated condition of the Berlin substation, which connects two 115-kV lines and one transformer.

Problems include obsolete relays, lack of protection for breaker or circuit switcher failures, lack of a back-up protection system, and lack of high-speed protection.

The control building lacks space to accommodate needed improvements, communication equipment and ancillary systems, Presume said, and its location does not meet National Fire Protection Agency (NFPA) requirements that it be more than 50 feet from any power transformer.

VELCO proposes replacing the control building and the protection and control (P&C) system, installing a breaker failure scheme and high-speed protection as the second scheme.

The New England Power Pool transmission facility portion of the costs is estimated at $5.9 million, and the non-PTF portion at $4.7 million, for a total project cost of $10.6 million (+/-10% accuracy and including 15% contingency).

Replacing the substation could cost up to seven times as much, Presume said.

Eversource 345-kV Structure Replacements

Eversource’s John Case presented the company’s plans to replace 1,483 345-kV structures at an estimated cost of $403.9 million (-25%/+50%).

The replacements will be light-duty tubular steel poles that comply with current clearance and strength code requirements. Eversource anticipates completion of the work in 2021.

After this replacement program, any future 345-kV upgrades that require PAC approvals will be brought forth on a line-by-line basis, Case said.

The company is supplementing foot patrols with high-definition cameras on drones, which allows inspectors to see possible damage from all angles, he said.

“The use of drones is phenomenal at getting right in there to see what’s going on; it’s a great tool,” Case said.

– Michael Kuser