Floating solar platforms

Energy Division

Designing, building, and installing a floating structure designed to host a photovoltaic solar platform on the Lac des Toules in Switzerland in partnership with Romande Energie S.A. and ABB.

Lac des Toules, Switzerland

The project involved three stages:

An initial photovoltaic generation test was conducted near the dam, on the shores of the lake, from 2013.

Poralu Marine helped to develop a floating solar farm to serve as a demonstrator, which was commissioned in 2019.

The farm was extended to cover 35% of the lake’s surface, with 67,000 m² of solar panels on approximately 1,000 floats anchored to the lake’s shores.

The project is a world first at high altitudes. Ultimately, it will generate almost 23 million kWh every year.

Because the project is located at high altitude (1810m),the challenging climate of the Alpine environment had to be taken into account in the design of the floating structure. Temperatures can plummet to -30°C, winds can reach 120km/h, the lake freezes (with ice up to 60 cm thick), and the area receives heavy snowfall (up to 50cm).

Currently, the farm covers 2,240 m². It is built on a floating aluminum alloy structure capable of withstanding the extreme conditions. The floats are made using high-density polyethylene. Romande Energie S.A. attached the solar panels to the structures, then placed them on the water as a unit.

The aircraft-grade aluminum structure requires little in the way of moorings and is attached to the bottom of the lake with weights, allowing the floating structure to rise and fall with the water.

Our main steps

1/ Understand the architecture & adopt a simultaneous design approach for both the floating structure and the superstructure.

2/ Propose anchoring systems tailored to environmental and regulatory conditions.

3/ Adopt a regulatory approach determined by each project’s location.

4/ Suggest the most economically viable construction method based on the final site.