Radiant: the rise of a green technology start-up supported by École Polytechnique

What is the goal of your start-up, Radiant?

Alexandre Meurisse: Our goal is to decarbonise industrial heating using our Belenos technology, which relies on concentrated solar energy. This energy heats air to 1,000 degrees, providing manufacturers with a carbon-free alternative to gas in their production cycles. Therefore, we offer a carbon-free alternative to fossil fuels that is also more cost-effective.

Where did the idea for Radiant come from? 

Thomas Delhon: I have been passionate about technology since childhood, and after completing my studies in aerospace engineering, I wanted to start a business. I was quickly drawn to solar concentration for space applications, and then I realised its potential for decarbonising industry. Alexandre and I then moved from space to biochar*, which stores CO₂, but we abandoned this to refocus on our solar concentration technology and its main advantage: producing carbon-free, competitive heat.

Alexandre Meurisse: I completed my PhD at the DLR in Cologne, Germany. This made it easier to establish contact with, and build mutual trust with, the researchers working on this project. They had been working on this solar concentration technology for around fifteen years. They were interested in scaling up this innovation to an industrial level, which is what we are doing with Radiant: turning knowledge into reality so that the research can benefit society as a whole.

Could you tell us about the support offered by the X-UP incubator at Polytechnique?

Alexandre Meurisse: We took part in the X-UP 17 programme, which ran from April 2024 to February 2025. We had excellent contact with the X Novation Centre team [Editor's note: École Polytechnique's entrepreneurship and innovation centre] and the other entrepreneurs on the programme. We have maintained these links. In fact, I am at École Polytechnique right now. We are also using the facilities at X-FAB, the X Novation Centre's prototyping space, for the technical part of our project. 

This support enables entrepreneurs to turn ideas into projects. 

Personally, it has given me a better understanding of entrepreneurship, a field that did not appeal to me as much as it did to Thomas, who was already familiar with it. 

Thomas Delhon: Yes, I took courses in entrepreneurship and management during my studies. 

The incubator offers a variety of beneficial workshops on topics such as legal issues, finance and communication. 

Furthermore, as École Polytechnique incubatees, we benefit from its network and the measures it has put in place to promote its start-ups. Thanks to École Polytechnique, we had the opportunity to participate in the Stage Two competition in Berlin from 28 to 30 October 2025. Around 40 European universities and schools sent their best start-ups to this event. After winning an internal competition organised by the Centre for Entrepreneurship and Innovation at École Polytechnique, we represented the school and France at the event. Out of a total of 40 start-ups, our start-up came first in this competition. 

What does this recognition mean to you?

Thomas Delhon: Winning this competition brought me immense joy. Alexandre and I would like to thank the X Novation Centre team, and École Polytechnique more broadly, for this opportunity. The incubator has had a huge impact on our company. Without its support, things could have turned out very differently, as demonstrated by the outcome of our latest fundraising round. 

How did the fundraising go?

Thomas Delhon: The fundraising, which took place in December 2025, went very well. We raised €2 million, primarily from Hexa, a prominent private investor in the start-up sector with a number of French unicorns to its name, as well as from business angels, the Tiresias Angels network, and Selim Chérif, an independent investor. 

These investments will enable us to approach the BPI and banks to secure further funding. 

What are the next steps for Radiant?

Alexandre Meurisse: Our main challenge this year is recruiting to expand our team. We hope to grow from three people [Editor's note: 2 founders and 1 employee in 2025] to ten people by mid-2026. We are particularly targeting engineers and salespeople. 

Technologically, we are working on installing a pilot site in Le Mans and enhancing the power of our solar energy receiving technology, with the aim of scaling up our innovation to an industrial level. We are also continuing our collaboration with the DLR.

This pilot site will also be used for full-scale testing with our future customers.

Thomas Delhon: We are looking for prospects in the glass, cement, and metallurgy industries, initially in France and then internationally. 

Alongside this showcase in Le Mans, we will be attending the ChangeNOW trade fair dedicated to sustainable development on 30 March, 31 March and 1 April 2026 to expand our network and attract potential customers. 

A new fundraising campaign will be organised at the end of 2026, and our first commercial projects with industrial companies will begin in 2027. 

What advice would you give to an aspiring entrepreneur or someone with a new business idea?

Thomas Delhon: Don't wait for the right moment to get started. The journey will be more difficult and take longer than you expect, but it will ultimately be more rewarding. Entrepreneurship is a worthwhile adventure!

Alexandre Meurisse: No entrepreneur starts out with the right idea from the outset. Mistakes are an inherent part of the entrepreneurial journey. It's by making mistakes that you find the right subject and market.

I also believe that it's important to start a business with a partner and/or seek support, given the scale of the task.

*In 2025, start-up company Neamine changed its name to Radiant and began offering Belenos, a new technology focused on solar concentration and the production of carbon-free industrial heat.