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.

In preparing for the congestion study that was released in September 2015, the Department published a Federal Register Notice, requesting comments on what publicly-available data and information should be considered, and what types of analysis should be performed to identify and understand the significance and character of transmission congestion. The Department then conducted a series of four regional pre-study workshops in the East and the West to receive input and suggestions concerning the Study, followed later by a series of webinars during which preliminary findings were shared with state officials and other stakeholders and input was requested. On August 19, 2014, the Department issued a Federal Register Notice announcing the availability of a draft of its National Electric Transmission Congestion Study for public comment. The public comment period closed on October 20, 2014. Submitted comments were posted online.  After reviewing and considering comments on the draft study, the Department prepared a final version of the study which was released in September 2015. 

Other previous congestion studies were conducted in 2006 and 2009.

Information about the 2019 congestion study is available HERE.

* 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.