Piène-Basse hydropower plant, retaining structures and water supply

1. Water reservoir on the Roya river: the installation was established in a rocky narrow bed of the Roya river, under the village.
2. Water supply between the reservoir and the power station: most of the pipe was dug in the rock, first on the right bank, then on the left bank of the Roya river. It is visible only when crossing the river, a little south of the village, in the form of a reinforced concrete tube, and before entering the plant in the form of the double metal tube of the penstock.
3. Hydropower plant: The plant is built on a narrow site between the Roya river and RD 6204 road, away from other buildings.

Period XX

Accessibility No

Visitable No

The Breil-sur-Roya hydroelectric generating unit was started in 1926 and commissioned around 1929, while the French and Italian Roya was in the process of electrification under the impetus of private companies.

A widening of the Roya river at the village level, followed by a rocky strangulation, was used to create a reservoir lake. In order to benefit from a maximum height of fall, the plant was established just north of the old Italian border marked by the Riou valley at Piène-Basse hamlet.

The water supply tunnel to the power plant is mostly underground, and has a very small difference in height to optimize the final waterfall in a double penstock. South of the village, an aqueduct crosses the Roya in the form of a tube carried by triangulated legs in reinforced concrete.

The Piène-Basse power plant, at an altitude of 230 m, impels the water captured at the gate of the village lake at an altitude of 280 m.

The building, built in 1926, presents the characteristics of modernist industrial architecture. Its halls are lit by large bay windows on the river side. A double reinforced riveted metal line runs along the slope from the exit of the adduction tunnel to the turbine room, crossing the Roya river.

Conditions of visit

Restricted access (private property)

Visite des installations réservée (propriété privée)1. Water reservoir on Roya river, downstream from Lake Breil, visible from the RD 6204 road bridge south of the village.
N-B: The Breil Lake was created by the restraint of the hydroelectric exploitation.
2. The gallery between the reservoir and the power station is dug into the mountain on most of its route. It is visible on two aerial plots:
– in the Sanfurian district, about 1 km south of the village: the pipeline passes in an aqueduct above the road RD 6204 and Roya;
– In front of the power station, the penstock that goes down on the left bank enters the building again crossing Roya.
3. Hydropower generation plant: the building is located at the edge of the RD 6204 road, north of Piène-Haute hamlet.


Additional information


  • Botton Charles, Histoire de Breil et des Breillois, Les Editions du Cabri, Breil-sur-Roya, 1996.
  • Braun Michel, L’électricité dans le Haut Pays Magazine Le Haut-Pays n°18, Les Editions du Cabri, Breil-sur-Roya, 1990.
  • Giusto Jacques, Tende : L’avènement de l’électricité Magazine Le Haut-Pays n°64, Les Editions du Cabri, Breil-sur-Roya, 2005.
  • Collectif, Laissez-vous conter l’hydroélectricité en Roya-Bevera, ADTRB, Sospel, Non daté.
  • Collectif, Paysages apprivoisés, Empreinte de l’homme sur la nature d’hier à aujourd’hui, en Roya et Bevera, Carnet d’exposition, ADTRB, Sospel, Non daté.