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Major solar project to be launched in Prafleuri

Sion, Hérémence and Lausanne, 19 December 2022 – Grande Dixence SA and the municipality of Hérémence have signed a letter of intent to develop a major alpine solar power project in collaboration with Alpiq. The project will be situated in the Combe (valley) de Prafleuri; a former quarry used during the construction of the Grande Dixence dam. The system will have the potential to produce 40-50 GWh of electricity a year, a large proportion of which in winter. The project demonstrates the partners’ desire to increase their contribution to securing electricity supplies in Switzerland and respond to current challenges. The aim is for the installation to come into operation by the end of 2025.

Grande Dixence SA and the municipality of Hérémence are currently working together with Alpiq to develop a project for a high-altitude solar power plant. The municipality has identified a suitable location for such a system at the Combe de Prafleuri. The site has a potential to produce 40-50 GWh of electricity a year, equivalent to the average annual electricity consumption of more than 11,000 households. A large proportion of the energy will be produced in winter, a distinct advantage given the growing shortage of electricity supplies at this time of year.
Initial reconnaissance of the site was conducted in late November. The first measurements were taken in early December. The construction of a measurement and testing system is planned in the next weeks. The aim will be to determine the site’s meteorological parameters more precisely and collect detailed information on the potential for generating solar power. This will help with drawing up the application for a construction permit, which the project’s initiators hope to submit before the end of 2023. The aim is for a large part of the installation to come into operation by late 2025. The project initiators will draw on Alpiq’s expertise and experience to carry out the various stages of the project within the short time frame available.

An especially favourable location

Situated at an altitude of 2,800 metres above sea level and south of the Pointe d’Allèves in Hérens valley in the municipality of Hérémence, the Combe de Prafleuri is an ideal location for setting up an alpine solar power plant. This ancient moraine was used as a quarry to provide materials required for the construction of the Grande Dixence dam between 1951 and 1961. A relatively flat area spanning some 350,000 m² has thus already been reshaped significantly by human activity. An environmental impact assessment will be conducted in the summer of 2023. At this stage, it appears that the project would have only a limited impact on the environment and the landscape. The project’s initiators will further strive to minimise this impact and integrate the project into the area as far as possible.
The existing infrastructure at the site is one of key advantages of the project; access roads are already in place, while a medium-voltage electricity line providing power to a pumping station is connected to the area around the dam. These installations would be used and renovated where necessary to transport the energy produced. ‘The Hérens valley is already home to one of Switzerland’s largest hydroelectric complexes in the form of the Grande Dixence. Developing a new project that addresses our current electricity supply challenges is thus in the same pioneering spirit,’ says Amédée Kronig, Director of Grande Dixence SA.

Ensuring supply security in winter

The Prafleuri system will be equipped with bifacial solar panels; photovoltaic cells that can produce electrical energy on both sides and are particularly effective at high altitudes. Solar radiation is significantly greater at altitude than on the Swiss plateau, and the cloud cover is relatively thin. Light reflection by snow increases production, while the low temperatures improve the operating conditions. Thanks to these factors, the overall production of solar power generators located at high altitude is almost double that of installations on the Swiss plateau, and the proportion produced in winter is also far higher. According to Michael Wider, head of Generation Switzerland at Alpiq and chairman of Grande Dixence SA, ‘The Prafleuri project fits perfectly into Alpiq’s strategy of developing renewable energy projects that improve our security of supply, while having a responsible impact on Nature and the landscape.’

Long-established partners

Grande Dixence SA and the municipality of Hérémence have been collaborating for more than 70 years within the framework of the operation of the Grande Dixence complex. ‘The development of the Prafleuri solar power project demonstrates our common interest in further enhancing this partnership and continuing to play a crucial role in the electricity supply in Valais and Switzerland,’ says Grégory Logean, president of Hérémence. The two partners are currently sharing the financing of the project. Support from Alpiq, the historic industrial partner of Grande Dixence, provides the necessary expertise in terms of both project management and the production and marketing of electricity. The project will be opened to investment by other stakeholders (e.g. electricity distributors or producers) at a later date.

A selection of photos is available to the media at the following address: Kindly include the copyright note ‘Grande Dixence SA’ in conjunction with all use thereof.

Further information on Grande Dixence:
Further information on Hérémence municipality:
Further information on Alpiq:

Media contacts:

Grande Dixence SA
Aline Elzingre-Pittet
Tel. +41 (0)21 341 2277

Hérémence Municipality
Grégory Logean
Tel. +41 (0)27 282 5026 

Aline Elzingre-Pittet
Tel. +41 (0)21 341 2277