“We have chosen TOPCon technology for our future French gigafactory for the production of solar cells”, rejoices Pascal Richard de Carbon

Barely three months after presenting its ambition to build a mega-factory for the production of photovoltaic cells and panels in France, Carbon has chosen its solar technology. The start-up announced on May 13 that it is joining forces with the international solar energy research center ISC Konstanz (Germany), which holds patents on tunnel oxide passivated contact technology (TOPCon). For Industrie & Technologies, the co-founder and president of the start-up, Pascal Richard, looks back on this crucial step and, more broadly, on the ambitious industrial project that he carries with conviction.

Industry & Technologies: You announced on May 13 that you had chosen to partner with ISC Konstanz. Why is this such an important step?

Pascal Richard: By partnering with ISC Konstanz, we have chosen to produce the TOPCon technology, on which this research center holds patents. This is an essential step: once the technological choice is made… let’s go! All the production processes, the sizing of the site where we want to set up, the technical specifications, and therefore the selection of manufacturers who will manufacture our equipment stem from this choice! We assume it fully, and we are in the process of explaining to the market, to investors, to the State, to Europe, etc. our decision.

Why did you choose to rely on TOPCon technology rather than passive emitter and rear contact (PERC) solar cells or heterojunction cells?

We are listening to the market, and one of the major standards in 2025 will be TOPCon technology. We can consider it as the advanced version of PERC: the efficiency of the cell goes from 22% to 24%. That’s a lot considering electricity production over 30 years! In addition, the TOPCon technology has the advantage of being able to evolve towards IBCs [cellules solaires à contact arrière interdigité, ndlr], without having to invest heavily in new machinery.

The other flagship technology, which is exploited by Carbon’s competitors, is the heterojunction cell. It’s good tech, but we’ve seen in TOPCon a trend of more robust international deployment in the coming years.

Other players have mastered TOPCon technology. Why did you choose ISC Konstanz?

The proactivity of ISC Konstanz will enable us to maintain our agility, which represents a differentiating factor for Carbon. In addition, there are already bases that produce ISC Konstanz cells internationally (in India and China, and PERC in Turkey), so this is strong support.

We are also in partnership with the Photovoltaic Institute of Île-de-France (IPVF), based in Paris-Saclay – with its teams from CNRS, Total Energies and EDF –, where we will probably work on solutions tandem for the technologies of tomorrow. Surrounded by two independent structures – the IPVF and the ISC Konstanz – we have a strong team that promises great things in record time!

What skills do you need to master to produce photovoltaic cells and panels?

There are three professions at Carbon. First, ingot and wafer production: polysilicon is melted to create ingots, which are then sawn very finely to make wafers. Secondly, there is cell production: we integrate TOPCon technology on the wafers. This step takes place in a clean room. Finally, there is the assembly of the cells in panels.

The production of cells and panels will certainly be located in Europe, but what about the supply of raw materials?

The main strategic input is polysilicon, which is made from quartz, coal and wood. Unlike other minerals, quartz is not only found below China or the Congo, it is one of the most common materials in the earth’s crust. There are a few players in Europe that produce polysilicon, such as the German chemist Wacker. There is nothing, on paper, that prevents us from recreating a completely integrated solar industry in France and Europe!

In addition, there are still areas of innovation on the manufacturing process side on which Carbon is working a lot: for the moment, when transforming the ingot into a wafer, we are losing 40%! We want to reintegrate these losses into the process to limit dependence on the market. Finally, remember that the panel, at the end of the chain, is 95% recyclable. We are also working on strategies for recovering solar panels at the end of their life to recover a quantity of components which themselves will return to the process.

Is the market receptive?

We are in a very advanced discussion process with customers. The big difference with other startups – especially in battery gigafactories – is that we won’t have a single customer who could take a stake. We want to serve the market.

About two-thirds of Carbon’s products will be sold (in the form of panels) to large energy companies, which have very massive electricity production demands. The last third will be intended for companies that assemble panels – there are around fifty in Europe – to whom we will sell solar cells. It is sort of a B to B industry, where we will co-construct a European offer.

Why are there no other initiatives of this magnitude?

Because investments are very important! We aim to become one of the top ten producers of solar panels worldwide, which currently does not include any Europeans. In 2030, we plan to install 20 GW of panels, which requires an investment of at least 5 billion euros. We have a first stage of 5 GW in 2025, which represents 1.2 billion euros of investment. Achieving such production volumes is essential to be competitive!

It’s a speed race. You have to know how to make decisions quickly, keep a certain agility for future fundraising. This is an entrepreneurial approach that has never been seen!

So it’s a hell of a risk…

We have initiated this reflection during the year 2020 with Pierre-Emmanuel Martin, president of the Terre et Lac group [producteur d’électricité solaire et développeur de projets solaires, ndlr] and Philippe Rivière, president of ACI GROUPE [ETI Française de sous-traitance industrielle, ndlr]. Observing a difficult situation regarding the supply of solar panels for the European market – linked to the Covid pandemic, but the trend was already earlier – led me to the following question: how to repatriate part of the value ? The creation of Carbon imposed itself.

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