The Lac d'Émosson (Lake Émosson) is a reservoir in the canton of Valais, Switzerland.

Water is then sent through a headrace tunnel to the 190 MW La Bâtiaz Power Station, 12 km (7 mi) to the east in Martigny, Switzerland.

The lake serves as the lower reservoir for the 900 MW Nant de Drance Hydropower Plant which began operations in 2022.

The Funiculaire du Châtelard is the first used from the valley bottom, it is the steepest 2-cabin funicular railway in the world with a gradient of 87 percent.

[3][4] Mini-Funiculaire d'Emosson runs next to the dam with a maximum incline of 73% for a difference of elevation of 140 m.