Data vintage: Q2 2026 · Sources: ISO-NE LGIP (Large Generator Interconnection Procedures) · FCM Rules §4.8 · FCA 20 Results (2024)
ISO-NE Interconnection Cost Framework
1
SIS Study Fee
$350,000 non-refundable (large gen >5MW). Covers ISO-NE and TO engineering time. Results published within 6 months. Developer receives project-specific cost responsibility breakdown including direct facilities and any shared Network Upgrades.
LGIP Section 6.4
2
Direct-Assigned Facilities
Generator lead, step-up transformer, protection upgrades, and revenue metering at ISO-NE-required interconnection point. Developer competitively bids construction. Typical range: $3–25M depending on voltage level and distance to POI.
LGIP Section 7.2
3
Network Upgrades
Transmission upgrades beyond direct facilities. If solely triggered by project: directly assigned. If shared: allocated by load-flow sensitivity factor (injection shift factor). Range: $10M–$1.2B+ (offshore wind aggregate projects).
LGIP Section 7.3
4
IFA (Interconnection Financial Assurance)
Posted at IA execution. Wind/Solar: $70/kW. Storage: $50/kW. Refunded 30 days after COD net of study cost overruns. IFA escalates if project misses M4 milestone. Letter of credit or cash accepted.
LGIP Section 8.3
5
FCM Security
Projects participating in Forward Capacity Market post Capacity Supply Obligation (CSO) security: $7.92/kW for capacity secured 3 years forward. Forfeited if project fails to achieve COD on time. Critical financing risk for offshore wind given construction delays.
ISO-NE FCM Rules §4.8
ISO-NE Cost Benchmarks by Technology
| Technology | Zone | Avg SIS NUC ($/MW) | IFA | FCM Security | Total Typical Range |
|---|
| Onshore Wind | ME | $15,000–$50,000/MW | $70k/MW | $7.92/kW (if FCM) | $5–30M total |
| Onshore Wind | NH / VT | $25,000–$80,000/MW | $70k/MW | $7.92/kW (if FCM) | $8–45M total |
| Utility Solar | WCMA / CT / RI | $30,000–$90,000/MW | $70k/MW | $7.92/kW (if FCM) | $8–55M total |
| Solar + BESS | All zones | $40,000–$120,000/MW | $70k+$50k/MW | Optional | $12–70M total |
| Standalone BESS | All zones | $20,000–$60,000/MW | $50k/MW | Optional | $5–35M total |
| Offshore Wind (Fixed) | SEMA / RI / CT | $100,000–$350,000/MW | $70k/MW | $7.92/kW | $100–500M total |
| Offshore Wind (Floating) | ME (future) | Est. $300,000–$600,000/MW | $70k/MW | TBD | $300M–$1B+ total |
Capacity Interconnection Rights (CIRs)
Definition
What Are CIRs?
Capacity Interconnection Rights are ISO-NE's mechanism for generators to participate in the Forward Capacity Market. A CIR grants the right to offer qualified capacity up to the CIR amount in each annual FCM auction. CIRs are attached to the specific interconnection point and cannot be easily separated from the project.
ISO-NE Tariff Schedule 17
Transfer
CIR Transfer Mechanism
CIRs can be transferred (sold) to another project at the same or a nearby interconnection point. This is particularly useful when a plant is retiring — the buyer acquires CIRs and avoids the full interconnection study process for a new project. CIR transfers require ISO-NE approval and Facilities Study confirmation.
LGIP Section 9.4
Risk
CIR Forfeiture Risk
If a project acquires CIRs (by winning capacity in FCM auctions) but fails to achieve commercial operation within 4 years, ISO-NE forfeits the CIRs and the developer loses all FCM security posted. This is a major financing risk for offshore wind projects facing construction delays — developers must carefully model delay scenarios.
FCM Rules §4.8(d)
Zone Value
Capacity Value by Zone
ISO-NE zones with higher capacity prices (CT at $4.10/kW-month, NEMA at $4.75/kW-month) offer higher CIR value than unconstrained zones ($3.89/kW-month). For a 200 MW project, the annual difference between NEMA and ME zone capacity value is approximately $2M/year — a material financing consideration.
ISO-NE FCA 20 Results
Offshore Wind Cost Trajectory
2019
Vineyard Wind SIS — First OSW Data Point
Vineyard Wind Phase 1 System Impact Study identified $450M in grid upgrades for Cape Cod cable landing at Barnstable. This was the first large-scale offshore wind interconnection cost data point in New England — shocked developers with scale of needed reinforcement.
2021
Revolution Wind SIS — RI Grid Upgrades
Revolution Wind (704 MW, RI) SIS identified $180M in Rhode Island grid upgrades including Davisville substation expansion and 115kV cable reinforcement near South Kingstown. Confirmed OSW landing sites require significant substation investment.
2022
New England Wind Facilities Study
New England Wind (1,200 MW) Facilities Study finalized $380M in upgrades for 3-cable RI/MA landing. First project to require a dedicated new 345kV substation for OSW aggregation. Set cost precedent for multi-cable OSW hubs.
2023
Sunrise Wind Acquires CIRs
Sunrise Wind (924 MW, RI/CT) successfully acquires CIRs in FCM auction. Commits to 2027 COD. SIS results show $220M in grid costs. Now carries 4-year COD obligation — any delay risks forfeiture of FCM security.
2024 Q2
ISO-NE LRTP Study Begins
ISO-NE launches Long-Range Transmission Plan (LRTP) study to plan grid for 30 GW offshore wind by 2035. Expected $6–12B of new transmission including potential HVDC backbone from ME to NEMA. Results expected 2026.
2026
Vineyard Wind Phase 1 COD
Vineyard Wind Phase 1 (800 MW) expected commercial operation — the first major offshore wind project in New England. Will establish cost precedent for grid reinforcement amortization and CIR value realization at Cape Cod landing point.
2030
Massachusetts 5,600 MW OSW Target
Massachusetts 83D mandate requires 5,600 MW by 2030. Requires 8+ projects beyond those currently in queue. Cost socialization mechanisms — spreading grid upgrade costs across ratepayers rather than all to developer — under active FERC review as a necessary policy tool.