Coloured photovoltaic panels are now being sold in France after technology to make them was developed in Switzerland.
Many homeowners find the standard dark grey and black solar panels ugly, especially when they are placed against the orange roof tiles found across much of France.
Now the panels can be made to match, with a thin coloured polymer film placed between the glass and the converters.
The technology, invented by the Swiss research unit Centre Suisse d’Electronique et de Micro-technique, in collaboration with a company called Solaxess, can only be applied when the panels are being manufactured – it is not possible to retrofit the coloured film.
Solaxess director Frédéric Clauss told The Connexion: “Our process is unique. Until now, coloured panels meant using coloured glass, and it is impossible to get the uniformity of colour our film allows.”
The performance of the panels drops according to the colour chosen, with white panels being the worst at 55% efficiency compared to standard black panels.
“The question is whether there would be any panels at all,” said Mr Clauss. “In many places, black panels are simply not acceptable for aesthetic reasons, so it is better to have 55% of solar electricity than none at all.”
Terracotta-coloured panels have around 80% efficiency.
Prices are approximately 10% higher than standard panels when they leave the factory, but demand is so strong that some installers charge significantly more for them.
Guarantees of performance are the same as for dark panels – most manufacturers offer cover for 15 years.
The majority of solar panels are made in China and Solaxess works with manufacturers there, as well as smaller German, Spanish and Austrian firms.
There are now two small solar panel manufacturers in France, but they say they have so much demand for dark panels that they have not yet had time to develop coloured ones using Solaxess technology.
Mr Clauss said the coloured panels have been accepted by some local authorities for installation near historic monuments, including in France, but this is not always the case.
“It all depends on the locality, local aesthetics and the renewable energy policy,” he said.
“If it is a long view towards a historic building, then our panels are excellent, especially if black ones are banned. But some people will still complain about coloured panels if they see them close up to historic buildings.
“We were able to produce panels to match roofs in the historic centre of Zurich, now producing electricity, where black ones have been banned for years.”