N-type Technology: “Things are moving much faster than anyone could predict”

Expert Interview – November 27, 2023

A rapid change in solar cell technology is becoming apparent – high-efficiency n-type solar cells with the three cell types of TOPCon, HJT and IBC are fast becoming the mainstream in cell production and are increasingly replacing p-type cells. What does this mean for the manufacturing industry, for distributors, and for installers?

Radovan Kopecek, CEO, CTO and co-founder ISC Konstanz

To find out more, we talked to Radovan Kopecek, CEO, CTO and co-founder of the International Solar Energy Research Center (ISC) Konstanz, an industry-related research institute that has been promoting the use of bifacial n-type cells since it was founded in 2005.

The ISC has already carried out eight n-type technology transfers with companies from Europe, China and India. “When China decides to adopt a technology, things move much faster than anyone could predict,” he says, assessing the current transformation process.

The solar industry is currently undergoing a technological shift from p-type to n-type cells. Can you estimate what percentage market share n-type cells will have in 2023, in terms of current production, the creation of new production capacity and existing installations?

To date, over one terawatt (TW) of production equipment has already been built for n-type cells. The problem the manufacturers have now, however, is that they can’t sell it. This is also due to the unilateral international trade restrictions concerning photovoltaics (PV) equipment that China has recently imposed on India. There’s a huge overcapacity there, not just in cell and module production in general, but simply too many production machines have already been built. PVinsights estimated 500 gigawatts (GW) of machines for n-type technologies by the end of 2023, whereas, in fact, there are now more than twice as many as that, so one terawatt!

We don’t have enough lines to accommodate all that yet, though.
The production capacity for n-type technologies is currently estimated at 400 GW, but the forecasts for 2024 are much clearer – it’s expected that 70 percent of next year’s production will come from n-type cells. The switch is happening quickly. TOPCon technology will account for 80 percent, heterojunction (HJT) for 10 percent and IBC for 10 percent.

How did this equipment surplus come about? Are the reasons for it similar to the “module backlog”?

There are four or five large machine manufacturers that probably just wanted to outdo each other and get their products out to both new and existing customers more quickly but overshot the mark.

How are the expansion, conversion and construction of n-type cell production facilities changing?

The large Tier 1 manufacturers, who already had high PERC capacity, are expanding. This mainly refers to TOPCon technology because PERC can be expanded very easily here. Newcomers will add further HJT and TOPCon capacity. This means that the large Chinese manufacturers will offer turnkey factories, allowing manufacturers who haven’t focused on PV before to simply order and acquire turnkey factories of several GW.

Put another way, it’s a combination of expanding the old lines and installing new TOPCon and HJT. The weight then goes more towards TOPCon due to the upgrades made to the old PERC lines and lower CAPEX and OPEX.

Which key players in the industry, like manufacturers or investors, are increasingly relying on n-type cells and why?

China has decided to switch completely from PERC to n-type technology, which means that no more investments are actually being made in p-type. This switch is happening too quickly, however – although there are manufacturers who know how to produce TOPCon well, not all of them do. The Tier 1 manufacturers in particular, who’ve been researching this for years and have experienced people, know what they’re doing.

But these new capacities, mainly from companies that are acquiring turnkey lines, will initially have difficulties producing high-quality products. I’d say you’d be well advised to buy the Tier 1 products first, even if they are perhaps a little more expensive.

As with PERC, there will be a period of uncertainty and then everyone will claim the technology doesn’t work and that everything happened far too quickly. But if you know what you’re doing, n-type technology is better than p-type. As solar cell processes are becoming more and more complex, there is of course a higher potential for degradation.

What criteria should installers or wholesalers use now when deciding to purchase n-type or p-type cells?

That’s difficult to say, as some PERC modules are still cheaper. You can now get PERC for 12 euro cents per watt-peak (Wp), for instance. You just have to do the math. On one hand there are the module costs, then there’s the datasheet with information on efficiency, degradation coefficients etc. on the other. It’s not as if I’m now telling people to only buy n-type modules because they’re better. We’re currently in the transition phase where p-type is still worthwhile, but n-type may or may not be better, depending on what’s on offer. In a year or two, however, p-type will no longer be worthwhile.

What are the advantages of n-type cells over p-type cells, and are there any disadvantages?

There are disadvantages. The technology is more complex, for starters, and there are more production steps. As a result, you have to understand what each production step is for and what problems might arise there. That being said, the modules are very stable. You can give guarantees for over 30 years, sometimes 50 years. The advantages are clear. You have higher front-side efficiency. P-type technology doesn’t exceed 22 percent within the module. N-type technology easily achieves over 22 percent, even over 23 percent in some cases. Then there’s higher bifaciality.

You have a lower temperature coefficient, which means that when it gets hot, the module performs better than p-type, and degradation is less if everything is produced properly.

What about the availability of materials?

The difference to p-type cells is that more silver is used. Silver is being partially replaced by copper. This is probably the most critical aspect of n-type technology. Critics like to emphasize that, as we enter the terawatt age – that’s to say, from 2027 when we’ll be producing more than one TW per year – there won’t be sufficient silver available. That’s not my opinion – we’re working very hard to reduce the amount of silver we utilize. This is an additional challenge we’ll also overcome.

Radovan Kopecek spoke to Sarah Hommel de Mendonça.

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