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2009 National Electric Transmission Congestion Study

Section 216(a) of the Federal Power Act, as amended by the Energy Policy Act of 2005, directs the U.S. Department of Energy (DOE) to conduct a study every three years on electric transmission congestion and constraints within the Eastern and Western Interconnections. Based on these studies, and comments concerning them from states and other stakeholders, the Secretary of Energy may designate any geographic area experiencing electric transmission capacity constraints or congestion as a national interest electric transmission corridor (National Corridor).

The 2009 study is the second Congestion Study that the Department conducted. The first Congestion Study was conducted in 2006. 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 will close on October 20, 2014. The draft study is now available for review and downloading at


The Federal Register Notice of Inquiry requesting comments and providing notice of a technical conference was issued on June 4, 2008.

Six public regional workshops were held from June 2008 to September 2008 to seek invited stakeholder input and discussion, including comments on practical metrics for gauging levels and significance of transmission congestion. 

A public technical conference on the 2009 study and historical transmission data and future transmission projections in the Western and Eastern Interconnections was held March 25-26, 2009.

The Department of Energy issued the 2009 National Electric Transmission Congestion Study in December 2009.

Comments submitted by the public after the 2009 Study was published are available for download.