Section 1221(a) of the Energy Policy Act of 2005, codified at 16 U.S.C. 824p(a), directs the Secretary of Energy to conduct an electric transmission congestion study every three years, and to prepare it in consultation with affected states and regional reliability organizations. In the study, the Department seeks to provide information about transmission congestion by focusing on specific indications of transmission constraints and congestion and their consequences. The study focuses on a specific time frame – e.g., historical trends over the past few years, and looking forward three to five years. The study is based entirely on publicly-available data and transmission-related documents. 

2023 National Transmission Needs Study

In the Bipartisan Infrastructure Law of 2021, Congress expanded the scope of the National Transmission Congestion Study, now called the National Transmission Needs Study (Needs Study), to include both historic and anticipated future capacity constraints and transmission congestion to more accurately identify high-priority national transmission needs. While the results of the Needs Study will highlight the greatest national transmission need, industry and stakeholder feedback is essential to informing DOE’s National Interest Electric Transmission Corridor (NIETC) designation process. This feedback can identify ongoing project roadblocks such as permitting, siting, or regulatory issues. Increasing stakeholder engagement is one way DOE is seeking to increase NIETC geographic specificity to drive concrete and timely action, spur additional transmission development to solve transmission limitations that are adversely impacting consumers, and improve environmental reviews. On May 9, 2023, DOE issued a Notice of Intent and Request for Information seeking feedback on final guidelines, procedures, and evaluation criteria for the designation process. 

2020 Congestion Study

The 2020 National Electric Transmission Congestion Study was released in September 2020 and is available on the Office of Electricity website: /node/4586274

A September 24 Federal Register notice announced the availability of the study for public comment. The comment period lasted 60 days and closed on Monday, November 23, 2020. After considering the comments, the Office of Electricity will prepare and publish a report summarizing and responding to the comments and indicating whether DOE intends to designate any specific geographic areas as National Electric Transmission Corridors.

In preparation for the congestion study, DOE published a Notice of “Procedures for Conducting Electric Transmission Congestion Studies” in the Federal Register in August 2018 and requested written comments by October 9, 2018. DOE subsequently extended the comment period by fifteen days to October 24, 2018. Public comments received by DOE in response to the Federal Register Notice are posted HERE.

Information about previous congestion studies is available HERE.


Annual U.S. Transmission Data Review

The U.S. Department of Energy (DOE) has broad responsibility for developing and supporting the implementation of energy policies that serve the public interest. Ensuring that timely and accurate data on key subjects is widely available to the public is one of those responsibilities. With that responsibility in mind, the Office of Electricity releases an Annual U.S. Transmission Data Review, its compilation of transmission-related data focusing on six areas:  transmission infrastructure, transmission reliability, transmission utilization, transmission constraints, transmission planning, and economic congestion. This data, which is gathered from publicly-available sources, is used to inform various DOE analyses, including OE’s triennial transmission congestion studies. The report does not draw conclusions about the transmission system—it is, instead, an effort to gather publicly available data in one place and to present it in a unified framework as comparably as possible.


The 2018 Annual U.S. Transmission Data Review is available HERE.

The 2016 Annual U.S. Transmission Data Review is available HERE.

The 2015 Annual U.S. Transmission Data Review is available HERE.