The 735-kV transmission line celebrates 50 years

The innovation that transformed Québec’s energy development

On November 29, 1965, Hydro-Québec commissioned the world’s first 735-kilovolt (kV) high-voltage transmission line. This Québec innovation transformed the course of Québec’s energy development by making it cost effective to harness the province’s tremendous water resources.

Thanks to this innovation, Québec chose hydropower, a clean and renewable source of energy, to drive economic and industrial development, rather than building thermal or nuclear generating stations.

Today, hydropower provides more than 99% of the electricity generated in Québec and Quebecers enjoy the lowest electricity rates in North America.

The optimal solution for Québec
By the early 1960s, electricity demand in Québec was growing rapidly, requiring that Hydro-Québec double its generating capacity every decade. A number of hydropower projects in the north seemed promising—the La Grande complex in the Baie-James region and Manic-Outardes on the Côte-Nord—but getting electricity to load centers in the south economically was a challenge that surpassed the existing power transmission technology.

While other countries were looking into developing 500-kV high-voltage lines, Jean-Jacques Archambault, a young Hydro-Québec engineer, was studying a voltage level never before considered: 735 kV.

In August 1962, the Québec Hydro-Electric Commission gave the project the green light. An army of engineers and technicians was mobilized.

A key breakthrough in the energy industry, the first 735-kV line contributed significantly to the international reputation for technical expertise earned by Hydro-Québec and the Québec electricity industry. Fifty years later, 735-kV transmission is used around the world.

735-kV transmission: still essential for the grid
Today, 735-kV lines are the main arteries of our transmission system, the largest in North America. On April 24, 2015, the Québec government announced the next step in the development of the 735-kV system: the Chamouchouane–Bout-de-l’Île project. The new line will ensure the continued reliability and efficiency of the Québec transmission system, as well as the long-term supply of major load centres.

Exhibition
A video on the construction of the first 735-kV line is currently being screened at the Électrium. Visits to the electricity interpretation centre are free.