The Time Seems Ripe for HJT

Only 2 years ago, our view on HJT would have probably looked pretty different. Yes, already at that time the highest efficient crystalline solar cell was based on heterojunction technology – an over 26% back contact HJT cell from Japan's Kaneka. And it was known that HJT on top of its superior efficiency comes with the best temperature coefficient and shows the highest bifaciality of all cell technologies. These advantages combined with the simplicity of manufacturing – 5 versus 13 production steps – has made HJT a compelling offer.

But on the commercial level it still looked rather bleak for HJT at that time. The technology's ray of hope SolarCity/Tesla was not able to ramp up its HJT based cell production in the US. Finally, Tesla got Panasonic on board, on the one hand an HJT pioneer, on the other hand, a niche manufacturer that has never been able to fulfil the huge promise of HJT.

At that time, the PERC express was starting to run full steam, satisfying customers' wishes for higher power ratings and quickly taking over the solar market in a landslide. The solar world has been quickly turning from multi to mono and from Al- BSF to PERC – and this transformation will be fully accomplished very soon.

With PERC being the new normal, solar companies will have to look for the next technology to up efficiency and reduce cost. In this regard, there is a lot of talk about TOPCon, which requires only one piece of additional production equipment to upgrade a PERC line. But the technology is very new, appropriate equipment just entering the market, and the efficiency potential only around 1% absolute higher than PERC.

Companies that really want to differentiate from the bulk will likely skip the TOPCon development step and directly jump onto HJT. That means higher investment cost but also higher efficiency cells – and the promise to have access to the only silicon cell technology with a bifaciality of over 90%. Jinergy is one early adopter expanding directly from PERC to HJT. The Chinese company has shopped around from a number of equipment providers that are now available and offer tools for different process steps. Jinergy is optimizing its 100 MW HJT pilot line and plans to expand to the GW level in about 2 years.

There are also former silicon thin-film companies that have re-configured their equipment to process HJT cells. Hanergy from China is one such company, another former Chinese thin-film company is GS- Solar, which said it has set up its own 600 MW production line and offers their HJT tools for sale to others. However, they've disclosed few details about their progress and equipment so far.

But eye-opening to us regarding HJT was REC, a mid-size but globally recognized premium module brand, which just announced to invest $150 million to expand into HJT. Unlike Jinergy, REC has purchased HJT cell and advanced module production tools with 600 MW capacity from one shop – Meyer Burger, which offers individual and turnkey HJT cell equipment, recently presented a 24.2% commercial design HJT record cell and has a roadmap towards 25%. REC, one of the first commercial manufacturers of PERC cells, apparently wants to be on the safe side when it selected Meyer Burger and signed a joint development agreement.

It seems the time for HJT is ripe, although it is too early to say how steep the growth curve of HJT will look like as the first commercial HJT lines (expect for Panasonic) are still in the starting phase. But with PERC market saturation and its efficiency limits in sight, global solar demand set to grow with 2 digits in the coming years and the pressure for solar power to compete without subsidies increasingly with wholesale electricity prices, the chances have been never as good for heterojunction technology as today.

This article is the conclusions part of our first TaiyangNews Heterojunction Solar Technology Report, which was released in March 2019 and can be downloaded for free here.