K2 substructure on the world's first floating solar installation in the mountains

K2 substructure on the world’s first floating solar installation in the mountains

24/01/2020 Reservoir ‘Lac des Toules’, Switzerland

Installation information

Location: Reservoir ‘Lac des Toules’, Switzerland
Height: 1.810 m.ü.M.
Wind conditions: wind at 120 km/h
Weather conditions: up to -30°C and 60 cm ice in winter
Start of construction: spring 2019
Completion: December 2019
Expansion (2021): 10 MW solar park
Yield: 800 MWh / annual consumption of around 220 households
System: special construction
Number of modules: 1.400 bifacial modules
Module field: 2.240 m²
Number of floaters: 36 floater
Investment: 2.4 million Swiss francs
Partner: Romande Energie, Swiss Federal Office of Energy, ABB

‘We want to prove that the output is around 50 per cent higher than in the valley’

‘We started planning the project seven years ago and installed a pilot plant near the reservoir. We tested suitable solar modules there, the right inclination and checked the technical and financial feasibility. With this project at ‘Lac des Toules’, we want to prove that it is possible to realise a floating PV project in alpine mountains, where the output is around 50 percent higher than in the valley,’ says Guillaume Fuchs, project manager at the energy group Romande Energie (interview).

‘The project will prove that a reservoir can be used twice. On the one hand for the production of hydroelectricity and on the other hand as a carrier for large-scale PV systems,’ says Lars Kreemke, project manager at K2 Systems.

Tailor-made substructure

The substructure was developed together with Romande Energie especially for this project and consists of high-density polyethylene floaters and aluminium rails that can carry high loads.

The floaters are also anchored to the ground with weights so that they can sink or rise depending on the water level.

‘The project has a 50 per cent higher efficiency’

‘The project has a 50 per cent higher efficiency than a comparable plant on land. Firstly, we use bifacial modules and secondly, there is higher UV radiation and lower temperatures above 1,800 metres, which makes the modules more efficient. Furthermore, the efficiency of the bifacial modules increases due to the stronger reflection of the snow in winter,’ says Guillaume Fuchs.

In addition, the project and the construction of the floating solar park benefits from the existing infrastructure on the reservoir, as it has already been used for electricity production for several years. ‘We think it is exciting and makes sense that someone is trying this out and gaining experience with it for the first time in the world,’ says Frank Rutschmann, Head of Renewable Energies at the Swiss Federal Office of Energy.

The project is the world's first floating solar power plant in the mountains on a reservoir that is emptied once a year.

Outlook: The target is a 10 MW solar park

The project will be expanded to a total of 10 MW from 2021 if the tests are successful. This corresponds to an area of about 30 football fields (218,000 m2).

The floating plant will then cover 35 per cent of the lake and supply electricity for 6,600 households.