Construction

The installation was financed and put in place by the Edisun Power SA company. Switcher SA made the roof space available free of charge.

Maintenance, operation

Edisun Power SA is responsible for maintenance and operation throughout the service lifetime. The suppliers for the project are bound by service contracts (guarantee to supply energy to the Lausanne Industrial Services power grid) covering operation and maintenance of the installation. Verification is the responsibility of the contractor or his deputy.

Building the photovoltaic installation

The installation has been sited as effectively as possible while respecting aesthetic criteria (mounting of the solar modules on the roof on strong foundations ? no roof penetration):

• Total roof area available: 700 m²
• Surface area of solar modules: 610 m²
• Angle of the solar modules: 24 degrees

Forecast energy yield

• Total 21,000 kWh/an
• 24.48 kWp * 850 kWh/kWp
• Summer 16,300 kWh/an
• Winter 4,700 kWh/an

The specific yield (850 kWh/kWp) was forecast on the basis of values arrived at from practical experience with similar installations and meteostandard 97.

Electrical installation

Having regard to the building characteristics, the voltage stabilizer (central stabilizer of the SolarMax DC 20 type ? a Swiss product) had to be placed in the cellar. The ambient temperature never exceeds 30°. Each row of solar modules is mounted in series (34 modules), connected in parallel (6 units) and wired up with a cable having a cross-section of 4mm2. The cables (fit for outdoor use) are led over the gravel-covered roof and run together to the terminal box mounted on external pedestals. The AC line joins up with the SIL grid via a three-phase supply cable.

Construction phase

Construction work on the roof of Switcher SA began in October 2002 and ended four weeks later. Thanks to very clement weather conditions (plenty of sunshine and very agreeable temperatures), the work was performed without difficulty and the photovoltaic installation was connected up to the SIL grid on 31 October. Edisun Power SA has checked power generation every day and reports with satisfaction that it is in line with the forecasts.

The technical problems were easily resolved and the project caused no major difficulties. Good cooperation between all the partners concerned (engineer, installation contractor, supplier, authorities, owner) enabled the installation work to proceed under optimum conditions.

The social and ecological commitment which forms an integral part of the Switcher SA philosophy made it an ideal partner for Edisun Power SA, as this photovoltaic installation demonstrates.

The Switcher photovoltaic installation proved to be a total success, as shown by its aesthetic side and the quantity of solar energy generated (making it one of the most important players on the SIL solar energy market).

All this should be a source of inspiration to visitors and encourage them to implement their own solar projects.

For further information, please contact :

Robert Kröni, Daniel Ruoss
Edisun Power AG
Lindhofstrasse 52
8617 Mönchaltorf
Tel : 044 994 90 01
Email : info@edisun.ch
Web : solarstrom.ch