The Office of Electricity Delivery and Energy Reliability has released the Annual U.S. Transmission Data Review, its annual compilation of transmission-related data focusing on six areas:  transmission infrastructure, reliability, utilization, constraints, 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. Until now, there has not been a single, inclusive, and authoritative annual transmission data summary that analysts can turn to readily. Over time, this summary may be broadened in scope if additional sources of transmission data become available.  

The 2015 Annual U.S. Transmission Data Review can be downloaded here.