Work is underway on both sides of the Cape Cod Canal to install new power line towers as NStar prepares to string a third major electrical transmission line to serve Cape Cod.
Cape Cod already has two transmission lines spanning the canal. The work currently being done in Bournedale and Bourne Village involves transferring those two lines from old lattice-style towers to new monopoles.
As soon as that work is done, a new, third 345-kilovolt transmission line will also be strung across the canal. This third line will serve as a backup if the other two transmission lines ever fail.
NStar spokesman Michael Durand said he expects the new line to be put in place by mid May.
To do that, NStar expects to use a helicopter to fly a “leader” line across the Cape Cod Canal. The new line will be attached to that leader (which does not carry power) and then will be winched across the canal.
Structures made with wooden telephones poles that look like two side-by-side football goal posts were put up on both sides of the canal as a safety measure. They were designevd to catch a line were one to fall during the transfer or installation work, keeping it off the roadways. Those structures will remain is place while the work is being done, and will be dismantled afterward, as the old lattice towers will be.
When the project was first introduced in 2010, experts said the new line would reduce the Cape’s reliance on what was then the Mirant Canal Plant in Sandwich (now called NRG Canal Power Plant).
The project, which adds about 18 miles of new transmission line running from an existing substation in Carver to a new substation in West Barnstable, has been forecast to cost in the neighborhood of $100 million.
In total, there will be 1.8 miles of new line in Bourne, alone, less than a mile of which will be on the military reservation. Much less work is needed to be done in Sandwich, although there has been some pole replacement and upgrading to accommodate the increased voltage that will result from the project.
Along with increased voltage and reliable power backup, the project will also result in a much more modern look in the Cape Cod Canal area, Henry V. Oheim of NStar said earlier this year.
The new approximately 100-foot tall towers are expected to have a much smaller visual impact than the existing multi-sided lattice towers now located on either side of the canal.