High Tech Industry

Calosol: more solar energy with new coating

In the EU, a total of 120 billion square metres – mainly on roofs and façades – are available for converting sunlight into electricity and heat. Together with partners, we’ve developed a method to transform façades into a source of energy. In this way, buildings can be made energy-positive relatively cheaply.

Innovative coating

At the heart of the solution is an innovative coating that we’ve developed together with AkzoNobel. Existing paints in the built environment often reflect the sun for cooling. By changing reflection to absorption, it’s possible to extract energy from sunlight. Our experts have developed ways of using the part of the solar spectrum that’s invisible to humans. This allows them to make paints in all colours, which absorb much more sunlight. For example, a colour white that has more than 30% higher solar absorption.

A simple way to make houses energy-positive

Around 60% of the energy consumed in houses and buildings is used for heating. A lot more can be achieved in this area. With the new coating technology and specially developed panels, between 40 and 100% of sunlight can be used effectively. This is of great interest with regard to renovations. More than 80% of the EU’s housing stock is pre-1990 and poorly insulated. With this new method, it’s quite easy to make houses energy-positive. The investment quickly pays for itself and is a good alternative to an air source or ground loop heat pump.

EU project

We’re coordinating the EU project ENVISION, which is developing the renovation concept. This involves the simple installation of a modular prefabricated structure. We wrap the house, as it were, and equip the roof with solar panels and the walls with solar heat collectors. In addition, the windows harvest energy from sunlight. Demonstrations of these solutions in various countries are planned for the near future.

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Dutch-German consortium develops simplified tandem solar modules for European market

14 March 2023

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Angèle Reinders new director Solliance

1 February 2023

Angèle Reinders, professor at Eindhoven University of Technology (TU/e), has been appointed Solliance's new director. Reinders will lead the new broad focus of the Dutch/Flemish/German solar energy partnership.

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Putting Europe back in the lead in solar panel production


Most solar panels come from China. Time to bring the solar panel production back to Europe. With smart solutions from TNO.

Solar energy


The Solar energy expertise group develops technology for solar panels, including bifacial solar modules and silicon solar cell technology.