January 13, 2012

Hot Report: Proposed New Electric Transmission Line

OLR Report 2012-R-0028 summarizes the proposal by Connecticut Light and Power (CL&P) to build a new transmission line in northeastern Connecticut and the alternatives CL&P considered in developing this proposal.

In December 2011, CL&P submitted an application to the Connecticut Siting Council for a certificate of environmental compatibility and public need to build a new 345-kilovolt (kV) overhead transmission line. The line would extend between CL&P's Card Street substation in Lebanon and the Rhode Island border in Thompson, approximately 36.8 miles long. It would pass through the towns of Brooklyn, Chaplin, Columbia, Coventry, Hampton, Killingly, Lebanon, Mansfield, Pomfret, Putnam, and Thompson. The project would also involve modifications to the Card Street and Killingly substations and the Lake Road switching station. The proposal is part of the larger Interstate Reliability Project, which calls for the construction of new 345 kV lines in northern Rhode Island and south central Massachusetts.


The vast majority of the proposed line would be adjacent to an existing 345 kV line within CL&P's existing right of way (ROW). Most of the structures supporting the line would be 85 feet tall, somewhat taller than structures on the existing line. The estimated capital cost for the project (including substation and station costs) is $218 million, assuming that CL&P's baseline design is used throughout. Over its 35-year life, the project would have a total cost (including interest and operating and maintenance costs) of $319 million.

Among the alternatives CL&P considered in making its application were (1) taking no action, (2) meeting reliability needs by additional generation or demand-side (conservation) measures, and (3) using highway or other existing ROWs for the transmission line, CL&P believes that these alternatives are either infeasible, more expensive, or more environmentally harmful than its proposal. The application presents six alternative transmission options involving overhead and underground lines, which CL&P believes are feasible, although less desirable based on cost and other grounds, than its preferred alternative.

For more information, read the full report.