Sologne: Sahara sand, pollen are enemies of solar energy


We assume that there are sheep on the site. We therefore want zero phytosanitary products, no transformed water and maximum use of water. This is how, at the beginning of April, Johnny Randoux explained the philosophy behind the cleaning of the 40,000 photovoltaic panels inaugurated by Photosol on the grounds formerly occupied by the Carrières de la Morandière in Gièvres. Between the waves of sand from the Sahara and the pollen, this is a potentially busy time for the maintenance manager at Photosol.

Dust generally interferes with the optimal functioning of photovoltaic panels. It is therefore particularly watched, even though it is “60% cleared by rain”, the specialist shows. However, monitoring the quantity and quality of production is essential. Especially at this time when the sand clouds in the Sahara regularly remind us of our good memories and require weekly monitoring.

“We are very careful about the amount of water used”

“The panel manufacturers provide us with a curve of their expected performance versus operating time. If the performance is consistent with what the curve says, we don’t interfere.”, explains Johnny Randoux. For each PV plant, a test is also carried out on a sample of panels that are constantly kept clean, again indicating the maximum efficiency that can be achieved. The loss of efficiency due to dust compared to the manufacturer’s instructions can reach a maximum of 3% or even 4%. If the performance of the panels is not at the same level, cleaning is necessary. “With clean water. We do not use any solvents »explains the technician.

Two processes are used. For panels that have an anti-reflective film, their friction is not considered. Photosol then uses a high-pressure cleaning system. “We inject water at 34 or 36 bar”, Johnny Randoux details. In the case of more conventional panels, the brush is passed through the water, either from a tractor or from a robot, depending on the configuration of the plot.

A particularly sticky pollen…

Does this mean that an astronomical amount of water is being released to ensure the correct level of renewable energy production? ” No way. We are very careful about the amount of water used”, assures the professional. Who does not deny that initially attention to the volumes of water consumed was not necessarily so scrupulous. But “Todaycontinues Johnny Randoux, the goal is to keep our panels as close to peak performance as possible, but wasting water is out of the question. We ask our service providers to pay attention to this and monitor their activity. »

In the viewfinder of a photovoltaic power producer, the main target in terms of dust is not necessarily what we think. “Often when the sands of the Sahara pass, it rains. The most annoying for us is clearly the spring pollen that disperses”, emphasizes the head of maintenance. Especially since he’s noticed since 2019 that oaks emit a particularly sticky pollen in the spring: “Once installed on your windshield, like PV panels, it dries out with wind and heat and is very difficult to remove”.

But when Saharan sand, pollen, and all other local sources of dust are combined, certain places need to be monitored more than others depending on their location. It’s cool in the middle of the fields. Near wooded areas, as is often the case in Sologne, it’s a different story. Experience has proven that, concludes the maintenance manager at Photosol “In order not to fall below the low yield threshold, it is best to clean photovoltaic parks every two years. This way we maintain the yield ».

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