MA — Power Infrastructure Updated 2026-07-17

Massachusetts

ISO-NE Data Center PPAs Transmission Constraints

1) Grid operator and market structure

2) Interconnection queue (status, depth, reforms)

  • Queue scope: ISO-NE’s interconnection queue tracks generation, Elective Transmission Upgrades (ETUs), and transmission service requests; it is not a comprehensive queue for distribution-level or behind-the-meter load interconnections. ISO New England Interconnection Request Queue, 2026-06-10
  • Data center visibility gap: Because data-center load requests can be handled through transmission-owner or distribution-company processes rather than the ISO generator queue, the ISO has begun collecting large-load information from transmission owners through a quarterly survey. ISO-NE Final Draft 2026 Large Load Forecast, 2026-03-27
  • Order 2023 cluster reforms: ISO-NE is implementing FERC Order 2023/2023-A generator-interconnection reforms through a cluster-study process. The transitional cluster study includes 26 generation/storage requests totaling roughly 8 GW of summer-rated capacity and is expected to be completed in August 2026. ISO New England Order No. 2023 Key Project, 2026-06-10; Utility Dive, 2025-10-21
  • Large loads are now entering the forecast, not the generator queue: ISO-NE’s 2026 process treats mature large-load projects as a load-forecast issue. Projects must be larger than 20 MW and have entered a formal study agreement to be included in the 2026 large-load forecast. ISO-NE Final Draft 2026 Large Load Forecast, 2026-03-27
  • FERC opened a regional large-load interconnection case: On June 18, FERC instituted Docket EL26-72-000, preliminarily finding that ISO-NE’s tariff may be unjust and unreasonable because it lacks clear, consistent provisions for studying and serving large loads, assigning upgrade costs, requiring financial security, and defining operational obligations. ISO-NE and participating transmission owners must either justify the existing tariff or propose reforms; the separate generation-adequacy report was due July 20 and the show-cause response August 17, so no final tariff rule existed at the July 17 cutoff. FERC order, 2026-06-18; FERC ISO-NE docket page, 2026-06-18

3) Ratepayer protection (large-load tariffs, cost allocation)

  • Existing DPU ESMP framework; no final data-center rate class: Massachusetts’ Electric Sector Modernization Plan framework requires utilities to plan and report on distribution investments, including large-load activity, but no Massachusetts DPU order adopting a data-center-specific rate class was located by July 17. Massachusetts DPU ESMP order, 2024-08-29; Mass.gov data-center framework, 2026-06-25
  • Executive framework directs future cost-allocation work: The June 25 framework says projects should bear the full cost of energy supply, grid upgrades, and interconnection; should not create congestion, reliability, or stranded-cost burdens; and should bring or fund clean generation sufficient for 100% of demand. It is guidance for agencies and for DPU action under existing authority, not an approved tariff. Mass.gov data-center framework, 2026-06-25; Mass.gov press release, 2026-06-25
  • HD.5404 remains pending: HD.5404 would require DPU review of distribution-company rates and cost attribution for large or qualified data centers of 10 MW or more so residential and income-eligible customers do not bear data-center construction or operating costs. Its only docket action remained referral to House Rules, and it had not become law by July 17. Massachusetts Legislature, 2026-07-17; Massachusetts Legislature PDF, 2025-12-05
  • H.5175/S.3166 is headed toward conference, not in effect: The House’s H.5175 would require utility data-center tariffs, an 80% renewable procurement condition for certain permits, and a battery-infeasibility showing before fossil-backup permits. The Senate struck that text and passed S.3166 on July 1; its data-center provision instead makes tax benefits conditional on future EOED requirements covering energy, affordability, grid optimization, water, environmental impacts, labor, community benefits, and reporting. The House non-concurred and appointed its conference members July 16, so neither approach had taken effect. Massachusetts Legislature bill history, 2026-07-16; Massachusetts Legislature House text, 2026-02-26; Massachusetts Legislature S.3166 PDF, 2026-07-01

4) Generation adequacy (projects, storage, shortfall concerns)

  • 2026 CELT adds large-load treatment: ISO-NE’s 2026 CELT cycle is the first to include a formal large-load forecast framework for data centers and other large loads. ISO-NE says New England has not yet seen the scale of data-center proposals occurring in other regions. ISO Newswire, 2026-05-18; ISO-NE Final Draft 2026 Large Load Forecast, 2026-03-27
  • Near-term large-load impact is zero in the ISO forecast: ISO-NE’s March 27, 2026 final-draft forecast says none of the included large-load projects are under construction, so the large-load contribution is zero for summer 2026, summer 2027, and winter 2026/2027. ISO-NE Final Draft 2026 Large Load Forecast, 2026-03-27
  • Included 2026 large-load projects: ISO-NE included only two proposed large-load projects in CELT 2026: a 200 MW data center in the NEMA load zone and an 85 MW general electrification project in Connecticut, both before derating. ISO-NE Final Draft 2026 Large Load Forecast, 2026-03-27
  • Derating assumptions for data centers: ISO-NE applies project-maturity derates and a 70% capacity-utilization derate to data centers, reflecting uncertainty in construction, energization, achieved capacity, and utilization. ISO-NE Final Draft 2026 Large Load Forecast, 2026-03-27
  • Forecast magnitude after derating: ISO-NE summarized the two large-load projects as at most 285 MW before derating, with forecast contributions of about 110 MW to summer and winter peak demand in the 2030s and about 130 MW in the 2040s; annual energy use is projected at roughly 800 GWh from 2030-2035 and 1,000 GWh in the 2040s. ISO Newswire, 2026-05-18
  • FERC now requires an explicit adequacy plan: The June 18 order requires ISO-NE to explain how the region will ensure adequate generation for existing and new large loads, including whether additional mechanisms are needed beyond current capacity and energy markets. That informational report was not due until July 20, after this file’s cutoff. FERC order, 2026-06-18

5) Utility load forecasts and IRP/plan filings

  • Planning framework: Massachusetts does not use a vertically integrated IRP model; regulated electric distribution companies file ESMPs and related annual/reliability updates that include distribution planning and load forecasts. Massachusetts DPU ESMP order, 2024-08-29
  • Large-load reporting direction: ESMP filings remain the principal existing Massachusetts utility-planning mechanism for large-load visibility. The June 25 framework calls for public disclosure of peak and annual energy demand, water use, fossil-fuel use, efficiency measures, employment, and whether a project has multiple distribution or transmission interconnection requests, but implementing rules were still under evaluation. Massachusetts DPU ESMP order, 2024-08-29; Mass.gov data-center framework, 2026-06-25
  • ISO-NE CELT 2026: The regional CELT forecast now includes a large-load forecast, while the general CELT report projects regional electricity consumption growth through 2035 driven primarily by heating and transportation electrification. ISO Newswire, 2026-05-01; ISO Newswire, 2026-05-18

6) Behind-the-meter (BTM), co-location, and direct PPAs

7) Transmission constraints and upgrades affecting data center siting

  • NEMA relevance: ISO-NE’s only included data-center large-load project in CELT 2026 is in the NEMA load zone, making northeastern Massachusetts/Boston-area transmission and distribution constraints especially relevant to data-center siting. ISO-NE Final Draft 2026 Large Load Forecast, 2026-03-27
  • Greater Boston and Massachusetts transmission planning: ISO-NE’s 2025 Regional System Plan continues to identify Massachusetts-area transmission needs and upgrades, including Boston-area and SEMA/RI reliability work, which can affect the feasibility and timing of new large-load interconnections. ISO-NE 2025 Regional System Plan draft, 2025-11
  • State permitting reform context: H.5175/S.3166 remained unresolved after the House appointed its conference members. The Senate text would also create a sustainable-economic-development-zones working group, including data-center operators, to recommend ways to accelerate electric connections without undermining climate requirements; it was not yet law. Massachusetts Legislature bill history, 2026-07-16; Massachusetts Legislature S.3166 PDF, 2026-07-01
  • Westfield illustrates project-specific interconnection timing: The proposed ten-building Servistar campus still needed an ISO-NE interconnection study and a developer-funded substation; Westfield Gas & Electric’s manager estimated the process at roughly five years. The project had not broken ground, underscoring that local approvals and tax eligibility do not establish a firm energization date. City of Westfield, 2026-06-15; The Shoestring, 2026-07-02

Notes on methods

  • Web search was used to update ISO-NE, FERC, Massachusetts Legislature, DPU, executive-agency, and local-government sources from February 1 through July 17, 2026.
  • The earlier opaque citation placeholders have been replaced with explicit markdown source links.