Neoen marks 10 years of large-scale photovoltaic production in Cestas

Neoen, one of the world’s leading independent producers of exclusively renewable energy, is celebrating the tenth anniversary of the commissioning of the Cestas solar park in Gironde, in southwestern France. With an installed capacity of 300 MWp, the site is made up of almost one million photovoltaic panels and generates an average of 345 GWh of carbon-free electricity each year – enough to meet the annual energy needs of over 240,000 residents (excluding heating). It was the most powerful photovoltaic facility in Europe when it was commissioned in 2015 and remains the most powerful solar farm in France to this day.

The solar park was developed in close collaboration with local stakeholders and built on former forestland devastated by Storm Klaus in 2009. Completed in under a year – an exceptionally short timeline for a solar park of this scale – its construction was a major industrial challenge, successfully met by a Franco-German consortium made up of Eiffage, Schneider Electric and Krinner. At the peak of construction, up to 250 people were working on site, with installation of almost 15,000 modules a day, equivalent to 5 MWp.

Other than its scale, the Cestas solar farm stands out for its innovative design. Its east-west orientation limits land use while optimising power generation: by facing panels in both directions, the plant delivers a more consistent electricity output throughout the day. Furthermore, since 2022, a groundbreaking partnership has been in place with RTE, the French transmission system operator. By granting access to a share of its inverters, the Cestas facility contributes to voltage regulation and thereby helps stabilise the grid, particularly during periods of low electricity demand. This innovation is unique in France and enables the plant to support the grid even when not generating power, including at night. The results of this pilot project have been highly positive, with significant impacts on high-voltage grid management in the Bordeaux area.

For the past decade, maintenance of the plant has been carried out by a consortium formed by Eiffage Énergies Systèmes and Schneider Electric, with around ten people working on site daily to oversee day-to-day operations. In addition, much of the site’s vegetation is maintained through eco-grazing involving a flock of 120 sheep.

A five-hectare area within the site has been preserved to support biodiversity. Environmental monitoring is conducted by independent ecologists who track the presence of local species and make recommendations to enhance their habitat. Bird nesting boxes, bat shelters and reptile refuges have been installed as part of this initiative. In addition, a hedgerow measuring 1,000 metres in length and comprising 120 fruit trees has recently been planted in partnership with the children from the Cestas youth council to encourage pollinating insects.

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