Floating solar platform on Lac des Toules

Bourg-Saint-Pierre Switzerland



Design, construction and installation of a floating structure intended to accommodate a solar platform on Lac des Toules, Switzerland, in partnership with Romande Energie S.A. and ABB.

The project will be carried out in 3 stages:

  • Phase one began in 2013, which tested the levels of photovoltaic production near the dam on the banks of the lake.
  • For phase two, a floating sample plant built with the support of Poralu Marine was launched in 2019.
  • Phase three will feature an extension of the floating park which will cover 35% of the lake’s surface. A total of 67,000 m2 of solar panels on approximately 1,000 floats moored to the lakeshore.

This is the world’s first project of its kind at a similar altitude. The project is expected to produce almost 23 million kilowatt-hours per year.


Technical details

With the project being located at high altitude (1810m), it was necessary to consider the strong climatic constraints of the Alpine environment when designing the floating structure. It would have to face conditions such as -30 C° temperatures, winds blowing up to 120km/h, freezing of the lake (60cm of ice) and heavy snowfall (up to 50cm).

The current plant measures 2,240 m2. It is supported by a floating structure made of an aluminum alloy, built to withstand extreme climatic conditions. The floats are made of high-density polyethylene. The photovoltaic panels were assembled directly on the structures by Romande Energie S.A., then the entire plant was launched into the water.

This floating aluminum structure is anchrored deep into the lake by using weights. The structure has the ability to adapt to the water level.



Poralu Marine designed, built, and installed the platform on the lake, in partnership with Romande Energie S.A.

Romande Energie S.A. press release (French)