Tokyo (SCCIJ) – World premiere in an alpine environment: The Swiss power company Romande Energie has commissioned the first floating solar park in an alpine environment. The large-scale power plant on Lake Toules (Bourg-St-Pierre, Canton of Valais), located at an altitude of 1,810 meters, faces extreme conditions but will deliver benefits through high energy efficiency.
The solar plant floats on Lake Toules, an alpine reservoir lake in canton Valais, at 1,810 meters above sea level (© Romande Energie).
A pioneering project
The innovative project began in August 2013, with the installation of a 60 square meter large pilot structure near the lake. It allowed the engineers to experiment with different types of solar panels and their inclination and to choose the solution best adapted to the project. The floating structures made of aluminum alloy and high-density polyethylene, as well as the photovoltaic panels, were assembled in spring 2019.
This lightweight structure was finally slid onto the water and connected to the grid this fall. It consists of a mat of 36 floats that, secured to the bottom of the lake with weights, will rise and fall with the water level. The dual-facility solar panels with a total area of 2,240 square meters produce more than 800,000 kilowatt-hours per year, equivalent to the annual consumption of nearly 220 households.
Challenging environment
The solar plant faces extreme conditions: Winds of 120 km/hour, winter temperatures down to -30°C, up to 60 cm of ice on the lake and 50 cm of snow on the surrounding mountains. But the benefits are enticing. This innovative installation should produce up to 50 percent more energy than a park of the same size located on the plain. The higher efficiency is due in part to the strong reflection of the sunlight on the snow. As the solar panels are bifacial and transparent, the light goes through them. They thus capture reflections on both the water and snow.
This is not the end of the project, though. The current installations are supposed to verify the technical and financial feasibility of an ever larger facility. It would finally cover 35 percent of the lake’s surface. The structure would have 67,000 square meters of solar panels. They would be attached to a bed of approximately 1,000 floats anchored on the lake’s banks. As a result, more than 24 million kilowatt-hours could eventually be produced each year from this Alpine lake.
Financial support of the Federation
Operator Romande Energie is quite proud of its endeavor: “We have already filed a patent application and want to facilitate and accelerate the energy revolution in Switzerland thanks to a world first,” said Pierre-Alain Urech, CEO of Romande Energie. The Swiss company Poralu Marine was in charge of its design, engineering, construction, and installation of the entire floating structure with the solar panels.
The Swiss Federal Office of Energy backs the project with 670,000 Swiss francs over three years, whose impact on the landscape and the environment remains limited. Lake Toules is an artificial lake formed by a dam. As it is emptied every year, there is nearly no wildlife in the lake. There are just a few fish released for recreational fishing.
Text: SCCIJ partly with material of Romande Energie and Poralu Marine
