ISO-NE’s multiyear effort to overhaul its forward capacity market likely will continue to dominate ISO-NE and NEPOOL work in 2025. The RTO’s workload also will feature a first-of-its-kind transmission procurement, compliance with FERC Orders 2023 and 1920, the development of an energy shortfall threshold and a myriad of other efforts focused on balancing affordability, reliability and decarbonization.
The capacity market already is a major revenue source for generators in the region and is poised to gain value as renewables supported by long-term contracts reduce prices in the energy market.
The RTO anticipates total revenue from the capacity market and power purchase agreements surpassing the value of the energy market by 2035. The capacity market was valued at $1.8 billion in 2023, while the energy market was valued at $4.8 billion.
Meanwhile, resource capacity accreditation changes, which have been under development since 2021, could significantly affect capacity revenues for different resource types.
ISO-NE has broken up the capacity auction reform (CAR) project into two phases, with the first phase focused on reducing the time between the auction and the capacity commitment period from years to months, and decoupling the resource retirement process from the capacity market.
The RTO plans to ramp up work with stakeholders on the detailed design for the first phase in early 2025, targeting a FERC filing by the end of the year. (See NEPOOL Markets Committee Briefs: Dec. 10, 2024.)
The second phase of the CAR project will focus on accreditation and seasonal reforms, which would split CCPs into distinct seasons with separate auctions. ISO-NE plans to begin discussions on these changes at a high level in 2025 before moving into more detail by the end of the year. It plans to file the second phase with FERC in late 2026.
The RTO reached an advanced stage with its accreditation reforms in early 2024 before pausing this work to widen the project scope. (See ISO-NE: RCA Changes to Increase Capacity Market Revenues by 11%.) ISO-NE told stakeholders in December that it plans to “explain and discuss all proposed changes to capacity accreditation … as if they are being presented for the first time.”
New Transmission and Aging Infrastructure
Also in 2025, the RTO is set to roll out its first request for proposals (RFP) for its longer-term transmission planning (LTTP) process, and likely will have to devote significant resources to complying with FERC Orders 1920 and 1920-A.
The LTTP process was developed by the New England states and ISO-NE and approved by FERC in July. It creates a process for selecting and paying for transmission projects to fulfill long-term needs identified in ISO-NE studies. (See FERC Approves New Pathway for New England Transmission Projects.)
In December, the states officially directed ISO-NE to develop the first LTTP RFP, which will be focused on increasing the north-to-south transmission capacity in Maine. ISO-NE plans to issue the RFP by March. (See ISO-NE to Work on State-backed RFP for Northern Maine Transmission.)
The LTTP process mirrors many of the requirements of FERC Orders 1920 and 1920-A, which direct transmission providers to adopt long-term transmission planning procedures and establish cost-allocation methods with the states. Order 1920 compliance filings will be due in the summer of 2025.
Prior to the release of Order 1920-A, ISO-NE paused stakeholder discussions on Order 1920 compliance, citing uncertainty regarding the pending rehearing order. It has yet to resume compliance discussions and has not announced whether it will pursue an extension of the compliance deadline. (See ISO-NE Announces Pause of Order 1920 Compliance Discussions.)
The orders do not directly require changes to the LTTP process. However, using parts of the LTTP process to comply with the orders would “require extra justification and could result in commission modification to those processes on compliance,” Day Pitney LLP, counsel for NEPOOL, said in a December presentation.
“The LTTP provisions might be better as an entirely separate supplemental process under the tariff,” Day Pitney added. “ISO, the [relevant state entities], the [participating transmission owners] and NEPOOL will need to consider.”
2025 also will bring continued scrutiny of asset condition projects, which are intended to address deteriorating transmission infrastructure. Asset condition spending by the region’s transmission owners has ballooned in recent years, and states and consumer advocates have raised alarms about a lack of transparency and oversight into the investments.
The region’s transmission owners have introduced over $3 billion in asset condition investments since the start of 2023, arguing that the investments are necessary to maintain the region’s aging grid. The states have pushed for reforms to the asset condition project review processes to ensure the investments are prudent, and also have expressed interest in right-sizing projects to capture long-term cost reductions when possible.
Interconnection
ISO-NE and stakeholders still are waiting for a response from FERC on their compliance filings for Orders 2023 and 2023-A. The RTO submitted its compliance filing in May, requesting that FERC approve the proposal by Aug. 12 to preserve the compliance timeline.
However, FERC has yet to rule on the RTO’s compliance filing for Order 2023, and ISO-NE has paused its work to implement its compliance with the order.
This delay has created significant uncertainty for projects in the interconnection process. The queue is closed for new projects, and likely will reopen only after the completion of the first cluster study, which will take about a year to complete after its initiation. If FERC requires significant revisions to ISO-NE’s proposal, this could further delay the start of the first interconnection study. (See New England Clean Energy Developers Struggle with Order 2023 Uncertainty and With FERC Inaction, ISO-NE Delays Order 2023 Implementation.)
“A commission order on the compliance proposal is sorely needed to help alleviate existing interconnection challenges and to provide certainty to both stakeholders and ISO-NE,” the New England States Committee on Electricity (NESCOE) wrote in a letter to FERC in late November.
“The continued uncertainty around the timing of an order places ISO-NE on a tightrope where it is forced to balance the need to be postured to move quickly toward compliance once an order is issued with the need to continue to process resources under the currently effective tariff,” NESCOE added.
At the state level, Massachusetts Energy Secretary Rebecca Tepper has said interconnection reform will be a major focus for Bay State energy officials in 2025. (See Overheard at Raab Electricity Restructuring Roundtable: Dec. 13, 2024.)
Reliability Backstops and Fossil Resources
ISO-NE also aims to establish a regional energy shortfall threshold (REST) in 2025, which likely will be a key factor in potential future out-of-market reliability actions to retain resources or ensure an adequate supply of stored fuel.
In November, the RTO said it plans to base the REST on two key metrics: normalized unserved energy over a 72-hour period — intended to capture the intensity of an energy shortfall — and total shortfall duration. (See ISO-NE Details Regional Energy Shortfall Threshold Metrics.)
ISO-NE plans to finish discussions on the REST metrics in early 2025 before proposing an initial risk threshold to stakeholders in March or April. These discussions could pose difficult questions about how much the region is willing to pay for reliability, and to what extent it will keep fossil resources online to support reliability as renewable generation increases.
The RTO’s inventoried energy program, which compensates fossil resources for maintaining fuel storage on-site in the winter, is set to expire in the spring of 2025. The RTO has yet to announce whether it plans to bring the program back for future winters.
In 2024, New England saw the closure of the 1,400-MW Mystic Generating Station, while Granite Shore Power announced its plans to retire Merrimack Station, the region’s last remaining coal plant, by 2028. While the coal generator struggled to pass an emissions test throughout 2023, one of the station’s two units passed the emissions test in July 2024. The other unit is not allowed to run until it passes the test.
Carbon emissions from electricity generation across New England likely increased in 2024 relative to 2023, according to ISO-NE data calculated through Nov. 25. The added emissions came from increased gas generation and do not account for gas system methane leaks, a key driver of climate change. (See Climate Activists Ask ISO-NE Board Members for More Transparency.)
ISO-NE has faced continued pressure from activist groups at public meetings to take a more activist approach to reducing power sector emissions. ISO-NE has said frequently it favors putting a price on emissions in the wholesale markets but would need unanimous state support to pursue this mechanism.
Consumer and environmental advocates also criticized for a lack of transparency into the proceedings of NEPOOL and the RTO’s board of directors. NEPOOL meetings remain closed to nonmembers, which has been a major point of contention for some environmental groups.
State Clean Energy Policy
To ensure resource adequacy amid the clean energy transition, new capacity additions must keep pace with resource retirements and load growth. ISO-NE projects peak demand to grow from about 24,800 MW in 2024 to 25,700 MW in 2030. The RTO expects load growth to accelerate after 2030, projecting peak demand reaching up to 57 GW in 2050.
New renewables are on the horizon — Vineyard Wind 1 and the New England Clean Energy Connect transmission line could come online by the end of 2025, potentially adding about 2 GW of combined generation capacity to the system. However, the subsequent wave of offshore wind projects likely will not be online until 2030.
The obstacles to large-scale renewable deployment are daunting; state policymakers and advocates face a less friendly federal administration, increasing costs and long delays for offshore wind projects and transmission lines, and mounting affordability pressures on ratepayers.
Two offshore wind projects, New England Wind 1 and SouthCoast Wind, remain in contract negotiations following their selection in the 2024 tri-state offshore wind solicitation. Connecticut declined to buy any offshore wind capacity from the solicitation amid worries about costs. (See Connecticut Closes the Door on 2024 OSW Procurement.)
New England states likely will pursue major new procurements in 2025, potentially building on the 2024 multistate coordinated offshore wind procurement. Massachusetts is authorized to pursue multistate clean energy solicitations through the end of 2025 and may pursue an additional offshore wind solicitation.
Maine is considering procurement of onshore renewable generation in the northern part of the state and also is developing its first offshore wind solicitation. Its first offshore wind RFP is scheduled to be finalized in January 2026.
New England officials have discussed the possibility of more transmission lines to Canada, which may be bolstered by an agreement in December between Eastern Canadian provinces that could lead to a significant increase in the country’s hydropower capacity.
With additional transmission capacity, Canadian hydropower could help balance renewable resources in New England, reducing reliability costs and renewable curtailment. While political and technical challenges remain, top energy officials in both Massachusetts and Quebec have expressed an interest in exploring the potential of new interregional transmission lines to unlock this potential. (See Overheard at Raab Electricity Restructuring Roundtable: Dec. 13, 2024.)