A collage of photos of transmission lines, solar panels, wind turbines, and battery energy storage systems

The Transmission Interconnection Roadmap (PDF) identifies solutions to enable interconnection processes to meet the growing demand for renewable energy resources from the rapid, widespread clean energy transition. Produced by the U.S. Department of Energy (DOE) Interconnection Innovation e-Xchange (i2X) and published in April 2024, this roadmap provides the diverse group of interconnection stakeholders with near- to long-term solutions to address current challenges in transmission system interconnection.

The rapid decarbonization of the U.S. electricity grid is driving a steep rise in requests to interconnect new clean energy generation resources like solar, wind, and battery storage to the transmission system. From 2000 to 2010, the United States averaged between 500 and 1,000 new transmission interconnection requests each year. Over the last decade, new requests have risen to 2,500–3,000 each year—a 300-500% increase. This backlog of requests can significantly delay clean energy deployment and lead to higher costs for project developers and electricity consumers. 

Interconnection processes need to evolve to handle the large number of requests today and into the future. In addition, technological innovations in data collection, analysis, and software management systems have created new opportunities to automate elements of interconnection processes.

The roadmap is organized around four goals, each critical to the overall mission of the DOE i2X initiative to enable a simpler, faster, and fairer interconnection of clean energy resources while enhancing the reliability, resiliency, and security of our electric grid. DOE developed the roadmap through extensive stakeholder engagement and outlines specific actions that each stakeholder group can take to improve interconnection. 

Download the full roadmap (PDF) and read more below about the goals, target metrics, and proposed solutions. Join the i2X team at a webinar to discuss the roadmap on May 8, 2024, from 1-2:15 p.m. ET. This will be the first in a series of five roadmap webinars. 

Transmission Interconnection Roadmap Goals

Goal #1: Increase Data Access, Transparency, and Security for Interconnection

Increasing interconnection data transparency would improve interconnection customers’ ability to screen and site potential projects, enable third-party modeling, facilitate process automation, enhance competition while ensuring equitable outcomes, and enable benchmarking, tracking, and auditing of interconnection processes and reforms. This goal recognizes the need to maintain data security by considering appropriate data access control programs while also increasing access to information on timelines, costs, and delays in the period after an interconnection agreement (IA) is signed. Increasing transparency can increase fairness, equity, and competition in the interconnection process while lowering the number of exploratory, ultimately withdrawn projects and increasing the proportion of high-quality, well-sited projects.

  • Improve the scope, accessibility, quality, and standardization of data on projects already in interconnection queues, including project attributes, cost estimates, and post-IA information.
  • Enhance the scope, timeliness, accuracy, and consistency of interconnection study models and modeling assumptions that transmission providers make available to interconnection customers.
  • Develop tools to manage, analyze, and visualize transmission and interconnection data made available in the previous two solutions, while ensuring secure data-sharing processes.

Goal #2: Improve Interconnection Process and Timeline

Interconnection backlogs and delays are often the result of rapid growth in interconnection requests, inefficiencies in interconnection processes, and staffing constraints. In the United States, interconnection queue volumes are likely to be large and potentially volatile for the foreseeable future. This goal covers solutions to improve queue management practices, affected system studies, inclusive and fair processes, and workforce development.

Queue Management

Several incremental queue management solutions—from automation and expanded access to fast tracks to more stringent commercial readiness requirements and study timelines—may help reduce queue volumes and interconnection delays in the near term and enable transmission providers to handle larger and variable queue volumes in the longer term. In the near term, transmission providers may face a trade-off between rationing interconnection queue space and maintaining open access.

  • Implement and enforce more stringent commercial readiness requirements, financial commitments, withdrawal penalties, and time limits that balance effectiveness, equity, and open access principles.
  • Implement and enforce interconnection study timelines and use incentives for minimizing delays in completing studies. 
  • Continue to automate parts of the interconnection process, such as data input and validation, some customer communications, and data sharing across processes and models.
  • Continue to monitor interconnection processing times and, as needed, develop one-off interventions for mitigating queue backlogs, such as additional temporary staff, outsourcing, temporary fast-tracking, and temporary rationing of queue space. 
  • Better use existing and create new fast-track options for interconnection, such as surplus interconnection service, generation replacement service, and energy-only interconnection service. 
  • Consider market-based approaches to rationing interconnection access.

Affected System Studies

Improvements to transmission provider coordination and methods for affected system studies—including the Federal Energy Regulatory Commission (FERC) Order 2023 requirements, but also voluntary collaboration and joint planning that go beyond them—will remove a significant obstacle to timely processing of interconnection requests. Work is needed to enhance coordination with non-FERC jurisdictional entities.

  • Increase voluntary collaboration on affected system studies, including harmonization of study procedures, study methods, data inputs, software tools, study criteria, and mitigation options. 
  • Conduct affected system studies using an energy-only modeling standard, unless interconnection customers have requested deliverability to the affected system. 
  • Develop a process to investigate new interregional transmission solutions through joint transmission planning efforts between neighboring affected systems. 

Inclusive and Fair Process

While all solutions of the roadmap aim to promote fair interconnection processes, not all stakeholders start with the same tools and resources. Enhancements to interconnection and transmission planning processes can help achieve inclusive and fair interconnection outcomes. Energy equity in interconnection requires intentionally designing systems, technologies, procedures, and policies for all types of interconnection stakeholders, including energy and environmental justice (EEJ) communities. The interconnection process could be made more inclusive and fairer by developing strategies to expand transmission connection access opportunities. 

  • Incorporate equity goals in transmission planning and valuation efforts.
  • Provide access to independent engineering, administrative, and legal services to support the navigation of interconnection processes. 

Workforce Development

Interconnection requires technical expertise across many professions in the electrical industry, from utility engineers to regulatory officials. There is a high degree of competition for these skill sets, as they require both engineering and policy experience. Targeted efforts to increase training opportunities for and improve compensation of existing staff will improve workforce capabilities, increase retention, enhance diverse and equitable representation across the interconnection workforce, and, as a result, expand processing of interconnection applications. Better advertisement of current interconnection-related positions and new outreach in higher education settings are needed to highlight the important role of interconnection policy and practice in the clean energy transition.

  • Assess the scale of interconnection workforce growth requirements
  • Upskill the existing workforce through continuing education programs.
  • Consider improvements to compensation and benefits while enhancing the advertisement and hiring processes for interconnection-related positions.
  • Grow the number of workers in the interconnection workforce via outreach, career counseling, apprenticeships, and curriculum development in postsecondary education. 
  • Expand education opportunities relevant to interconnection for under-resourced and EEJ communities. 

Goal #3: Promote Economic Efficiency in Interconnection

This goal addresses solutions that aim to improve cost allocation, reduce costs to electricity consumers, enhance the coordination between transmission planning and the interconnection process, and optimize the rightsizing of transmission investment through improvements in interconnection studies.

Cost Allocation

Expanding options for interconnection service and proactive transmission investments should reduce uncertainty and improve efficiency of cost allocations. If current efforts to reduce interconnection bottlenecks prove unsuccessful, transmission providers may need to consider more radical departures from the current participant funding model of interconnection cost allocation.

  • Explore options for identifying and allocating the costs of proactive transmission investments, including different options for state, federal, and participant funding. 
  • Ensure that generators have the option to elect energy-only interconnection and be re-dispatched rather than paying for network upgrades
  • Explore and evaluate potential options for delinking the interconnection process and network upgrade investments to increase up-front interconnection cost certainty. 

Coordination Between Interconnection and Transmission Planning

Closer alignment in the data inputs, assumptions, and process timelines between interconnection and long-term transmission planning can help ensure that transmission solutions that would have been more efficiently identified in transmission plans are not instead triggered through the interconnection process.

  • More closely align data inputs, assumptions, and process timing between interconnection and transmission planning processes. 

Interconnection Studies

Interconnection study methods will also need to continually adapt to a changing generation mix, with a greater emphasis on more realistic dispatch assumptions, consideration of multiple time periods rather than static snapshots, and inclusion of all potential mitigation options to relieving transmission constraints. Interconnection study solutions could help right-size transmission upgrades and reduce electricity consumer costs. As methods change, greater harmonization across transmission providers would help ensure more consistent outcomes across regions. 

  • Evaluate all effective mitigation options during interconnection studies, incorporating alternative transmission technologies as well as control options for inverter-based resources (IBRs). 
  • Continue to develop and harmonize new, transparent best-practice study methods to adapt to a changing generation mix and changes in load, as well as to facilitate consistent outcomes across transmission providers. 
  • Explore options to allow interconnection customers to self-fund and provide their own interconnection studies, subject to transmission provider oversight, rules, and requirements. 

Goal #4: Maintain a Reliable, Resilient, and Secure Grid

In recent years, a series of large disturbance events has led to significant IBR disconnection. These performance issues were not identified during interconnection studies of the involved plants. The solutions under this goal aim to reduce these gaps by updating technical requirements within interconnection studies, models, and tools while also improving industry interconnection standards.

Interconnection Reliability Assessment Models and Tools

Improvements to the models and tools used in interconnection studies and reliability assessments are needed to avoid large disturbance events that may threaten grid reliability. Collection and assessment of electromagnetic transient (EMT) models are needed today, while screening tools should be developed to determine when EMT studies become necessary in a specific region in the future. Aligning the interconnection study process flow with project development timelines will ensure the appropriate, site-specific models are used in system impact studies. Leveraging modern computing technologies should increase modeling capabilities. 

  • Require submission of verified EMT models for all IBRs during the interconnection process and develop screening criteria to determine when EMT studies are necessary within a region.
  • Develop rules for dynamic model quality testing and validation for both root-mean-square (RMS) and EMT simulations, ensuring that plant performance conforms with applicable interconnection requirements. 
  • Develop a study process flow that is better aligned with project development timelines.
  • Advance the computational speed of interconnection reliability assessments. 

Interconnection Standards

To ensure reliable and secure operation of newly interconnecting plants, comprehensive interconnection standards are necessary. Interconnection requirements specifying IBR capabilities and expected project performance remain a work in progress. Furthermore, current requirements lack performance specifications for accompanying phenomena during voltage or frequency disturbances such as transient overvoltage, voltage phase angle jump, and high rate of change of frequency. Finally, development of and compliance with cyber and physical security standards need to be incorporated into the interconnection process.

  • Adopt and implement a harmonized and comprehensive set of electricity generation interconnection requirements or standards, consistent with Institute of Electrical and Electronics Engineers (IEEE) Standard 2800-2022. 
  • Adopt and implement harmonized requirements for power plant conformity assessment as a part of generator interconnection procedures (GIPs) and consistent with IEEE P2800.2, once approved. 
  • Assess need for new interconnection requirements and standards to cover expected performance from emerging technologies
  • Evaluate cyber and physical security concerns during the interconnection process. 
  • Investigate the relationship between the interconnection process and system reliability issues. 

Measurable Targets for Interconnection Reform

This roadmap includes four target metrics for 2030 that can be measured using publicly available data:

  • Decreasing average time from interconnection request to interconnection agreement for completed projects to less than 12 months.
  • Lowering the variance of interconnection costs for all projects to less than $150 per kilowatt.
  • Increasing completion rates for projects that enter the facility study phase to greater than 70%.
  • Eliminating annual North American Electric Reliability Corporation (NERC) disturbance events involving unexpected tripping of IBRs that are not identified in analysis due to inaccurate IBR models. 

Additional Information