Overview
This report assesses how the U.S. electric power system currently interconnects large loads and provides recommendations for creating a more harmonized, transparent, and efficient interconnection framework. It focuses on the rapid proliferation of data centers and other high-demand facilities, including cryptocurrency mining, hydrogen electrolyzers, advanced manufacturing, arc furnaces, and electric vehicle fleets.
Produced by the Energy Systems Integration Group's Large Loads Task Force — one of 11 task force reports — the assessment maps current interconnection practices across select utilities and ISO/RTO regions, identifies gaps and bottlenecks, and draws on lessons learned from a decade of generator and inverter-based resource interconnection reform. It was prepared by Kyle Thomas of Elevate Energy Consulting and Julia Matevosyan of ESIG, with contributions from ERCOT, ICF, NextEra, Diode Ventures, and Elevate Energy Consulting, and supported by the U.S. Department of Energy through Lawrence Berkeley National Laboratory.
Why it matters
Large load interconnection requests have grown exponentially in both number and magnitude, reshaping load forecasts in nearly every region. The U.S. Department of Energy estimates national electricity demand will grow 15% to 20% over the next decade and could double by 2050 under certain scenarios — a reversal of a long period of flat or declining demand.
The scale is already evident in the queues. As of March 2026, ERCOT's large load interconnection queue held more than 410 GW across 551 requests, 88% of them data centers, against a record peak demand of 85.5 GW. MISO reported more than 13 GW. Nationally, more than 650 planned data center projects would add over 176 GW of peak demand.
Yet the processes handling these requests were largely designed for loads under 50 to 100 MW. Load facilities are not required to register with NERC and therefore have no applicable reliability standards, even though a 1 GW data center can affect the bulk power system far more than a 20 MW wind plant. Underpinning every other challenge is an unresolved jurisdictional question: which authorities — FERC, NERC, states, ISOs/RTOs, or utilities — govern large load interconnection standards and procedures.
Key challenges explored
The report examines several large load interconnection challenges, including:
Significant variation in interconnection processes across utilities and regions, many relying on ad hoc procedures
Inadequate coordination and information-sharing between utilities and ISOs/RTOs
Fragmented pathways across distribution, sub-transmission, and transmission levels
Open questions about which reliability studies are required and who performs them
Incomplete or absent performance requirements at the NERC, state, ISO/RTO, and utility levels
Insufficient models and data to characterize large load behavior
Cost allocation frameworks that lack structure and clarity
Speculative requests clogging queues and distorting load forecasts
Limited and inconsistently defined treatment of co-located load and generation
Flexible interconnection options that are unevenly available and poorly understood
Threshold gaming through strategic project sizing
Material modification processes outpaced by the rate of technology change
Staffing constraints at utilities and ISOs/RTOs
Observed reliability events, including the July 2024 loss of more than 1,500 MW of northern Virginia data center load across 60 facilities
Questions this resource helps answer
This resource helps stakeholders consider questions such as:
What does a complete large load interconnection process look like, milestone by milestone?
How do interconnection approaches differ across utility types and between ISO/RTO and non-ISO/RTO regions?
Which grid reliability studies should be conducted for large loads, and which entities should run them?
How should co-located large loads and paired generation be studied — gross or net, and under what conditions?
What performance requirements should apply, and who defines, mandates, and enforces them?
How should direct interconnection and network upgrade costs be allocated?
How can interconnection processes incentivize "bring your own generation"?
How can non-firm, provisional, and surplus service accelerate connection where firm service isn't available?
What can large load interconnection learn from FERC Orders 2003, 2023, and 901?
How do distribution-connected large loads differ, and where should requirements align?
What does the European Union's Demand Connection Code offer as a model?
What the report covers
Key sections include:
Issues with the interconnection process
Overview of the large load interconnection process, including seven distilled milestones
Differences in transmission interconnection processes across four utility types
The evolving role of ISOs/RTOs
Interconnection studies: power flow, PSPD, short-circuit, and EMT
Data and model requirements, and the absence of uniform national performance requirements
Lessons learned from large generation and IBR interconnection
Current approaches at Grant PUD, Southern Company, El Paso Electric, PJM, ERCOT, SPP, NYISO, CAISO, and MISO
Common challenges across ISO/RTO regions, with stakeholder perspectives and regional responses
Recommendations for transmission-connected large loads
Opportunities for federal action, including the DOE ANOPR's 14 principles and NERC's Large Loads Action Plan
Distribution-connected large load interconnection, including flexible and bridging interconnections
Conclusions and recommendations
Key recommendations
Interconnection process overall: Establish uniform, transparent processes built on clearly defined milestones, readiness requirements, roles, timelines, and cost allocation frameworks. Explore a FERC Large Load Interconnection Procedure analogous to existing generation procedures, which states and non-FERC entities could adapt. Apply site control and financial readiness requirements to filter speculative requests, implement consistent financial security and withdrawal penalties, finalize material modification rules, and expand early use of hosting capacity maps.
Coordination: Enhance utility and ISO/RTO coordination through formal information-sharing protocols and joint study procedures, improve queue transparency, and integrate large load interconnections into regional transmission planning.
Studies: Transition to cluster study approaches once request volumes exceed a preset level, ideally combining large load, generation, and planned transmission projects into one integrated planning study. Perform steady-state, PSPD, and short-circuit studies for every interconnection, establish a screening process for EMT studies, and harmonize methods for studying co-located load and generation.
Technical requirements: Develop clear lifetime performance and capability requirements with detailed PSPD and EMT modeling submissions, unify conformity assessment practices nationally, develop NERC large load–specific reliability standards, and create a NERC registration category for large loads.
New solutions to speed interconnection: Develop harmonized voluntary flexibility products — provisional, surplus, and non-firm service — and establish clear rules for bring-your-own-generation and co-located resources.
Staffing: Ensure utilities and ISOs/RTOs have sufficient staffing to process growing request volume and complexity.
Who this resource is for
This report may be useful for:
Utilities, transmission owners, and transmission operators
ISOs and RTOs
FERC, NERC, and state public utility commissions
Data center developers, owners, and operators
Large industrial and manufacturing load customers
Generation developers pursuing co-located projects
Grid planners and interconnection engineers
Distribution utilities and cooperatives
Consumer advocates and ratepayer representatives
Policymakers and economic development agencies
Equipment manufacturers and OEMs
Consultants and researchers working on load integration