US Interconnection Queue Analysis: What the 2025 Data Actually Shows

The US interconnection queue has become the dominant constraint for energy infrastructure development. This analysis examines current queue data across all major ISOs, withdrawal rates, capacity trends, and practical implications for project developers.

Key Findings

Total queued capacity has grown 5x since 2020, from approximately 550 GW to over 2,700 GW as of Q1 2025.
Withdrawal rates remain high at 60–75%, meaning the queue is larger than actual development intent would suggest—but still represents unprecedented demand.
Data center load has surpassed renewable generation as the primary driver of new interconnection applications in PJM and ERCOT.
Queue reform efforts (FERC Order 2023, ISO-specific reforms) are beginning to show impact in ERCOT and MISO, but PJM remains severely backlogged.
Transformer and equipment lead times (18–36 months) are creating a secondary bottleneck that the queue data doesn't capture.

Queue Volume by ISO (Q1 2025 Estimates)

| ISO/RTO | Queued Capacity (GW) | YoY Change | Data Center % | |---------|---------------------|------------|---------------| | MISO | 2,700+ | +28% | ~22% | | PJM | 1,200+ | +15% | ~38% | | ERCOT | 500+ | +41% | ~29% | | CAISO | 400+ | +8% | ~14% | | ISONE | 85+ | +12% | ~11% | | SPP | 350+ | +19% | ~8% | | NYISO | 60+ | +7% | ~18% |

Note: These figures represent applications filed, not approved or under construction.

Data Center Load as a Queue Driver

The composition of the interconnection queue has shifted dramatically since 2020. Traditionally dominated by generation projects (solar, wind, battery storage), the queue now includes a significant and growing share of load interconnection requests from data centers.

PJM Queue Composition Change (2020 vs 2025):

2020: 92% generation, 8% load
2025: 68% generation, 32% load (primarily data centers)

This matters for strategy. Generation interconnection studies and load interconnection studies follow different processes and timelines. Data center developers are entering a queue infrastructure designed for generation, without understanding the differences.

Key process differences for load interconnection:

Load projects often have more flexibility in delivery point selection
Load projects can qualify for existing customer delivery without full interconnection studies in some cases
Utilities may offer fast-track processes for large industrial loads that don't apply to generation

Withdrawal Rates: What They Tell Us

High withdrawal rates (60–75% of applications never complete interconnection) might suggest the queue problem is overstated. It's not.

Why withdrawal rates are high:

Speculative filing: Some developers file applications to "hold a place" without firm development intent
Study cost surprises: When first study results arrive, many projects are uneconomic. Projects withdraw rather than pay for expensive upgrades
Site control loss: Projects lose optioned land during long queue waits
Capital constraints: Financing dries up. Projects die, applications withdrawn

The net effect: Even at 70% withdrawal rates, the remaining 30% of applications represent a generation of infrastructure that must be built. 2,700 GW × 30% retention = 810 GW of real projects needing grid interconnection.

FERC Order 2023 and Queue Reform

The Federal Energy Regulatory Commission issued Order 2023 in July 2023, the most significant overhaul of interconnection rules in 20 years. Key changes:

Cluster Study Process: Projects are grouped into clusters and studied together, rather than sequentially. This theoretically reduces individual study time.

Application Requirements: More rigorous upfront requirements (site control, financial deposits) designed to reduce speculative applications.

Practical Impact (12 months post-implementation):

MISO and CAISO have shown modest improvement in study initiation times
PJM is still working through a massive backlog of pre-FERC 2023 applications
ERCOT (not subject to FERC authority over retail) has implemented its own reforms

Timeline to meaningful queue relief: Industry consensus is 2026–2027 before FERC 2023 reforms meaningfully reduce backlogs at the largest ISOs.

Equipment Lead Times: The Hidden Second Bottleneck

Interconnection queue analysis focuses on study timelines, but there's a second constraint that doesn't appear in queue data: equipment lead times.

Current lead times (Q1 2025):

Large power transformers (345kV+): 24–36 months
Medium power transformers (115–230kV): 18–24 months
High-voltage switchgear: 14–20 months
Underground transmission cable: 12–18 months

Why this matters: A project that clears its interconnection study in 18 months can still face 24+ month delays waiting for transformers. Projects that don't begin procurement during the study period add the full equipment lead time to their energization timeline.

The solution: Begin long-lead equipment procurement during the interconnection study period, not after study approval. This requires either project financing commitment before study completion or equity bridge financing for procurement.

Geographic Concentration Risk

Northern Virginia (PJM): Has absorbed 30+ GW of data center load in the last decade. Available capacity in the core market (Loudoun County, Prince William County) is effectively exhausted. New projects are being forced to Tier 2 markets (Western Virginia, West Virginia, Pennsylvania) or out of PJM entirely.

Dallas-Fort Worth (ERCOT): Still has capacity but is tightening rapidly. The 2021 winter storm exposed grid reliability concerns that have influenced utility planning. New projects face more scrutiny on load profiles.

Phoenix (APS/SRP): High demand, water constraints. Not a transmission problem but a water-cooling constraint that's increasingly binding.

Iowa (MidAmerican/MISO): One of the fastest-growing markets due to lower land costs, tax incentives, and MISO capacity availability. But transmission export constraints limit large loads.

Columbus, Ohio (AEP/PJM): Emerging Tier 1 market. AEP has been proactive about capacity planning for large loads. PJM queue constraints still apply.

What This Means for Projects Being Planned Now (2025–2027)

If you're planning to energize in 2026: Your window for filing interconnection applications has largely closed for most PJM markets. Focus on sites with existing transmission infrastructure or available customer service capacity.

If you're planning to energize in 2027: You have a narrow window. Applications filed in Q2-Q3 2025 with complete documentation and strong utility pre-engagement can realistically achieve 2027 energization in ERCOT or select MISO markets. PJM 2027 is very difficult.

If you're planning to energize in 2028–2030: More manageable, but queue reform needs to work as designed. Plan for the cluster study process. Budget for 24+ month equipment lead times starting now.

Hedging strategy: Given queue uncertainty, leading operators are filing in multiple markets simultaneously and pursuing multiple sites per market. The cost of parallel applications is small relative to the option value of timeline flexibility.

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