Saint Lawrence River HVDC Powerline Crossing

The Saint Lawrence River HVDC Powerline Crossing is the crossing of Hydro-Québec's Quebec-New England HVDC transmission line under the Saint Lawrence River between Grondines and Lotbinière, Quebec, Canada. The crossing is remarkable for being first implemented as an overhead crossing and later replaced by a cable tunnel. Hydro-Québec wanted to complete the transmission line in time, which was only possible with an overhead crossing of the Saint Lawrence River. However, due to the negative visual impact of the large towers of the overhead crossing on the local populations of Grondines and Lotbinière, it was decided to build a cable tunnel under the river, although this made the project more expensive.

Tunnel data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).