The U.S. Department of Energy (DOE) has introduced a comprehensive roadmap to expedite the integration of clean energy sources into the national transmission grid.

The Transmission Interconnection Roadmap outlines solutions for aligning interconnection processes with the increasing demand for renewable energy resources, which is driven by the rapid and widespread transition to clean energy.

The Interconnection Innovation e-Xchange (i2X) roadmap, released in April 2024, offers a range of solutions to diverse interconnection stakeholders, addressing both short-term and long-term challenges in the transmission system interconnection process.

The swift decarbonization of the U.S. electricity grid has resulted in a sharp uptick in requests to connect new clean energy generation sources such as solar, wind, and battery storage to the transmission system.

Between 2000 and 2010, the United States saw an average of 500 to 1,000 new transmission interconnection requests annually. However, over the past decade, this number has surged to 2,500–3,000 annually—an increase of 300-500%.

This backlog of requests has the potential to impede the deployment of clean energy significantly and result in heightened expenses for both project developers and electricity consumers.

A recent report by DOE’s Lawrence Berkeley National Laboratory reveals a substantial increase in generation and storage capacity seeking grid interconnection, with nearly 2,600 GW actively in the queue.

This surge has led to uncertainties, delays, and added costs for developers, consumers, utilities, and regulators.

Since the enactment of the Inflation Reduction Act (IRA), over 1,200 GW of capacity (including more than 500 GW of solar, over 540 GW of storage, and 125 GW of wind) have applied for interconnection.

Interconnection procedures must adapt to accommodate the substantial volume of current and future requests. Moreover, technological advancements, particularly in data gathering, analysis, and software management systems, have opened up new possibilities for automating aspects of interconnection procedures.

The roadmap is structured around four key objectives, each essential to the overarching goal of the DOE i2X initiative: facilitating a simpler, quicker, and more equitable interconnection process for clean energy resources while enhancing the reliability, resilience, and security of our electrical grid.

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

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

Transmission Interconnection Roadmap Goals

Goal 1: Enhance Data Accessibility, Transparency, and Security for Interconnection

Enhancing transparency in interconnection data would empower customers to evaluate and select potential projects, facilitate third-party modeling, streamline process automation, foster competition while ensuring fair outcomes, and enable the monitoring, tracking, and auditing of interconnection processes and improvements.

This objective acknowledges the importance of upholding data security through appropriate access control measures while expanding access to information regarding timelines, costs, and delays following the signing of an interconnection agreement (IA).

Solutions:

• Enhance the breadth, accessibility, quality, and standardization of data pertaining to projects already in interconnection queues, encompassing project characteristics, cost projections, and post-IA information.
• Improve the extent, timeliness, accuracy, and uniformity of interconnection study models and modeling assumptions provided by transmission providers to interconnection customers.
• Develop tools for managing, analyzing, and visualizing transmission and interconnection data made available through the preceding two solutions, ensuring secure data-sharing protocols.

Goal 2: Enhance Interconnection Process Efficiency and Timeliness

Interconnection backlogs and delays often stem from the rapid increase in interconnection requests, inefficiencies within the interconnection processes, and limitations in workforce capacity.

In the United States, it’s anticipated that interconnection queue volumes will remain significant and potentially volatile in the foreseeable future. This objective encompasses solutions aimed at improving queue management practices, impacted system studies, inclusivity, fairness in processes, and workforce development.

Queue Management

• Implementing stricter commercial readiness criteria, financial commitments, withdrawal penalties, and time constraints can help balance effectiveness, equity, and principles of open access.
• Enforcing interconnection study timelines and offering incentives for minimizing study delays.
• Continuing to automate certain aspects of the interconnection process, such as data validation, customer communications, and data sharing across processes and models.
• Monitoring interconnection processing times and implementing interventions as necessary, such as additional temporary staffing or temporary fast-tracking.
• Enhancing existing fast-track options and introducing new ones, like surplus and energy-only interconnection services.
• Considering market-based approaches to rationing interconnection access.

Goal 3: Foster Economic Efficiency in Interconnection

This objective focuses on solutions to enhance cost allocation, minimize costs for electricity consumers, improve coordination between transmission planning and the interconnection process, and optimize transmission investment through advancements in interconnection studies.

Expanding interconnection service options and proactive transmission investments can reduce uncertainty and enhance the efficiency of cost allocations. Should ongoing efforts to alleviate interconnection bottlenecks prove ineffective, transmission providers may need to explore more significant departures from the current participant funding model for interconnection cost allocation.

Solutions:

• Explore various methods for identifying and allocating the costs of proactive transmission investments, considering state, federal, and participant funding options.
• Ensure that generators have the choice to opt for energy-only interconnection and potential re-dispatch instead of bearing the costs of network upgrades.
• Investigate options to decouple the interconnection process from network upgrade investments to enhance upfront interconnection cost certainty.

Coordination Between Interconnection and Transmission Planning

Enhancing alignment in data inputs, assumptions, and process timelines between interconnection and long-term transmission planning can prevent transmission solutions that would be more efficiently identified in transmission plans from being triggered through the interconnection process.

Solution:

Align data inputs, assumptions, and process timing more closely between interconnection and transmission planning processes.

Goal 4: Ensure Grid Reliability, Resilience, and Security

In recent years, significant disturbances leading to the disconnection of inverter-based resources (IBRs) have highlighted performance issues not identified during the interconnection studies of the involved plants.

The solutions outlined under this goal aim to minimize these gaps by updating technical requirements within interconnection studies, models, and tools and enhancing industry interconnection standards.

Solutions:

• The submission of validated electromagnetic transient (EMT) models for all IBRs is required during the interconnection process, and screening criteria must be established to identify when EMT studies are necessary within a region.
• Develop regulations for dynamic model quality testing and validation for root-mean-square (RMS) and EMT simulations, ensuring plant performance aligns with relevant interconnection requirements.
• Devise a study process flow that better aligns with project development timelines.
• Enhance the computational speed of interconnection reliability assessments.

DOE Support to Implement Solutions

DOE has multiple roles in implementing the solutions identified in the roadmap, such as facilitating solution adoption, providing funding and technical assistance, and supporting the research community.

Its Grid Deployment Office invests in accelerating the interconnection of clean energy generation through the $5 billion Grid Innovation Program, which supports the deployment of projects that use innovative approaches to enhance grid resilience and reliability.

DOE’s Solar Energy Technologies and Wind Energy Technologies Office recently released a $10 million funding opportunity for analytical tools and approaches to accelerate interconnection.

They will also lead a series of forthcoming public forums to implement interconnection standards to maintain a reliable, resilient, and safe grid.

Through the Title 17 Clean Energy Financing Program, the Loan Programs Office seeks to finance energy infrastructure projects, including infrastructure investments to support transmission interconnection, reconductoring transmission lines, and upgrading voltage.

The department also supports electric vehicle charging deployment through the Joint Office of Energy and Transportation (Joint Office). The Joint Office is convening stakeholders to identify gaps between transmission and transportation planning to accelerate transmission development within transportation rights-of-way.

DOE plans to release a draft companion roadmap focusing on the distribution grid in the coming months.