Quebec – New England Transmission
The Quebec – New England Transmission is a long-distance high-voltage direct current line between Radisson, Quebec and Sandy Pond in Ayer, Massachusetts. As of 2012, it remains one of only two Multi-terminal HVDC systems in the world and is "the only multi-terminal bipole HVDC system in the world where three stations are interconnected and operate under a common master control system".
History
Initially, the Quebec – New England Transmission consisted of the section between the Des Cantons station near Windsor, Quebec and the Frank D. Comerford Dam near Monroe, New Hampshire which, because of the asynchronous operation of the American and Québec power grids, had to be implemented as HVDC. This bipolar electricity transmission line, which is overhead for its whole length except the crossing of Saint Lawrence river, went into service in 1986. It could transfer a maximum power of 690 megawatts. The operating voltage was ±450kV or 900 kV from line to line.The line was planned to extend beyond the two terminals at Des Cantons and Comerford to the hydroelectric power plants of the La Grande Complex, in the James Bay region of Québec, and to the high consumption area around Boston, Massachusetts — specifically, by 1,100 kilometers to the north toward the converter station at Radisson Substation, and to the south to the converter station at Sandy Pond in Massachusetts. The transmission power was increased by extending the existing converter stations to 2,000 megawatts, with the value of the transmission voltage remaining unchanged at ±450 kV. For the connection of the Montreal area, a further converter station at Nicolet was put into service in 1992 with a transmission capacity of 2,000 megawatts.
The line crosses the Saint Lawrence River between Grondines and Lotbinière via an tunnel. Until the tunnel was built, the line crossed the river via an overhead lattice tower electricity pylon—portions of one of these towers would later be used as part of the observation tower at La Cité de l'Énergie in Shawinigan.
Failed Northern Pass initiative
In December 2008, Hydro-Québec, along with American utilities Northeast Utilities and NSTAR, created a joint venture to build a new HVDC line from Windsor, Quebec to Deerfield, New Hampshire, with an HVDC converter terminal built in Franklin, New Hampshire. Hydro-Québec will own the segment within Quebec, while the segment within the US will be owned by Northern Pass Transmission LLC, a partnership between Northeast Utilities and NSTAR. Estimated to cost US$1.1 billion to build, it is projected that the line will either run in existing right-of-way adjacent to the HVDC line that runs through New Hampshire, or it will connect to a right-of-way in northern New Hampshire that will run through the White Mountains. This line, projected to carry 1,200 megawatts, will bring electricity to approximately one million homes.In order to go ahead, the project must receive regulatory approval in Quebec and the United States. The proposed transmission line could have been in operation in 2015. According to Jim Robb, a senior executive from Northeast Utilities, New England could meet one third of its Regional Greenhouse Gas Initiative commitments with the hydropower coming through this new power line alone.
In October 2010, Northeast Utilities announced that it would merge with NSTAR, with the resulting company initially retaining the Northeast Utilities name. The deal is subject to regulatory approval. In effect, Northern Pass Transmission would become a wholly owned subsidiary of Northeast Utilities, which would be renamed Eversource Energy in 2015.
The purchase of power from Hydro-Québec was an issue during the Massachusetts gubernatorial election of 2010.
In July 2019, Eversource issued a statement that the Northern Pass project was now "off the table" after investing $318 million over a decade to develop and promote the project.
Massachusetts is now pursuing a similar project that would bring Canadian hydropower through transmission lines in Maine. The proposed New England Clean Energy Connect is estimated to cost $1 billion.
Sites
Important waypoints of the line.Radisson to Nicolet
Nicolet to Des Cantons
Des Cantons to Comerford
Comerford to Ayer
| Site | Coordinates |
| Frank D. Comerford Dam / Comerford converter station, Monroe, New Hampshire, USA | |
| Merrimack River, East Merrimack/Litchfield, New Hampshire, USA | 42°53'42.24"N 71°27'34.40"W |
| New Hampshire / Massachusetts state line Hudson, New Hampshire / Tyngsborough, Massachusetts, USA | 42°41'58.47"N 71°25'45.75"W |
| Ayer, Massachusetts, USA |
Des Cantons to Deerfield
Route listed here reflects the primary route, and is currently projected.| Site | Coordinates |
| Des Cantons station, Windsor, Quebec, Canada | |
| Des Cantons Grounding Electrode Windsor, Quebec, Canada | |
| Border crossing between USA and Canada / Connecticut River | |
| Northumberland, New Hampshire, USA | |
| Whitefield, New Hampshire, USA | |
| North Woodstock, New Hampshire, USA | |
| Beebe River, New Hampshire, USA | |
| Ashland, New Hampshire, USA | |
| Pemigewasset River, New Hampshire, USA | |
| Southern HVDC Converter Terminal, Franklin, New Hampshire, USA | |
| Oak Hill, New Hampshire, USA | |
| Deerfield, New Hampshire, USA |