Table 8.10.B. Proposed Transmission Capacity Additions by High-Voltage Size, 2014 - 2020
(Circuit Miles of Transmission)
 

Voltage Circuit Miles
Type Operating (kV) Year 2014 Year 2015 Year 2016 Year 2017 Year 2018 Year 2019 Year 2020 All Years
AC 100-199 918 1,516 519 313 358 187 129 3,940
AC 200-299 667 827 180 409 69 68 178 2,400
AC 300-399 1,184 954 653 450 1,003 124 159 4,528
AC 400-599 6 292 -- 60 19 -- -- 377
AC 600+ -- 14 -- -- -- -- 499 513
AC Total   2,775 3,603 1,353 1,232 1,450 380 965 11,758
DC 100-199 -- -- -- -- -- -- -- --
DC 200-299 -- -- -- -- -- -- -- --
DC 300-399 -- -- -- 188 72 -- -- 260
DC 400-599 -- -- -- -- -- -- -- --
DC 600+ -- -- -- -- -- -- -- --
DC Total   -- -- -- 188 72 -- -- 260
Grand Total   2,775 3,603 1,353 1,420 1,522 380 965 12,018

Notes:
NERC region and reliability assessment area maps are provided on EIA's Electricity Reliability web page: http://www.eia.gov/cneaf/electricity/page/eia411/eia411.html
Circuit miles do not equal physical miles on the ground; the reference terminology for that concept is structural mile.
Some structures were designed and then built to carry future transmission circuits in order to handle expected growth in new capability requirements.
Lines are taken out of service for a variety of reasons including intentional changes to the right-of-way to better useavailable land for different levels of voltage and types of poles and towers.
Source: U.S. Energy Information Administration, Form EIA-411, "Coordinated Bulk Power Supply and Demand Program Report."