I got my answers. A colleague met them during an event. The have customers in Asia, it is already a thing there and they are currently trying to grow in Europe.

If you are living in an area where it is cold in the winter, having a cooling coating on your roof is probably not the best use.

Every roof is not proper to get solar PV, it can be shaded for example. And you can find many application besides roofs : cooling vehicules like buses or trains or bus and train stops. Current applications are used also for technical appliance : pipes, outside electrical closet…

PDRC also comes as fabric, it would be possible to use it to cool down a small street between to building, or make a cooling hat, or a folding awning for houses, a car cover…

Too bad the article is not explaining why SNCF is interested in this project. I can guess that electricity is one of the job of SNCF, they are using a lot of it, they have the skills and network to manage and distribute electricity. They could buy less electricity. Since rails are a well equiped infrastructure, it’s cheaper to put PV in place and everything is available for cables and it’s an electricity network by itself

I found some articles (in french). They already tested a solution to rapidly deploy PV on unused tracks : https://www.groupe-sncf.com/fr/innovation/solveig-prototype-ferrovoltaique

An another article is about this project and gives a bit more details : https://lenergeek.com/2026/02/06/une-startup-suisse-ose-limpensable-produire-de-lelectricite-directement-sur-les-rails-de-train/ It is an experimental project to find if PV panels could survive in such condition and if it is possible to manage both rail and energy operations on the same network.