Seite 2: New life in "Solar Valley

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The result of this strategy can be seen in a symbolic place: the "Solar Valley", an unglamorous industrial area near Bitterfeld-Wolfen. This used to be the heart of the German photovoltaic industry, shaped by the then world market leader Q-Cells. Last year, Meyer Burger moved into the empty 27,000 square metre hall of the solar producer Sovello, which went bankrupt in 2012. Europe's only cell production facility is being built there. It is to become the nucleus of a rebirth of the German solar industry. The first cells are already coming off the production line, and other production lines are being installed alongside.

At the beginning of production are millimetre-thin, fragile silicon wafers. When they arrive, they have already completed a world tour. The raw material polysilicon comes "one hundred percent" from Europe and the USA, emphasises Gunter Erfurt. But to process it into ingots and wafers, it has to go to China. "There is still no other way," Erfurt regrets. To make itself more independent, Meyer Burger recently signed a supply contract with Norwegian Crystals, one of the last two European wafer producers. But that only covers part of the demand.

Process optimisation for wafers

Employees manually insert the wafers into a carrier rack that is reminiscent of a CD stand from the 90s. All other steps are automatic. Whirring conveyor belts and hissing suction pads, shielded by glass boxes, transport the wafers through chemical baths, coating chambers and screen printing machines.

"We have reduced the number of process steps from more than ten to four," says production manager Jochen Fritsche: chemical pre-treatment, passivation, coating with a conductive surface, printing of silver conductive tracks. In the process, the wafers change colour from shiny metallic to silvery matt to the typical shimmering dark blue.

Much of the process optimisation is fine-tuning: for coating, for example, the wafers only lie on a transport frame at the very edge. This means that the top and bottom sides can be treated at the same time. Another work step is saved.

Another improvement: "At no point in the process do the cells get hotter than 300 degrees - and only for a few minutes," says Fritsche. In conventional processes, on the other hand, temperatures of more than 1,000 degrees prevail for several hours. Energy consumption and waste are correspondingly lower, and the heating and cooling phases are correspondingly shorter.

The real secret lies in passivation. It is supposed to reduce charge carrier losses on the surface. In "heterojunction" cells, a thin layer of amorphous silicon is applied on both sides. This should not only increase voltage and current, but also the conversion of diffuse light. In addition, the modules are bifacial, i.e. they can use light from both sides. According to Meyer Burger, the result is an efficiency of up to 25 percent at cell level, about a quarter more than conventional silicon back-contact cells. The heterojunction cells are also said to be more durable and less temperature-sensitive. Meyer Burger offers a 30-year warranty on glass-backed modules.

Employees from the past are coming back

People only have to lend a hand again to pack the finished cells for onward transport to Freiberg in Saxony. There they are assembled into modules - also in a reactivated solar factory. It belonged to the defunct Solarworld group, stood idle for years, but was still equipped with well-maintained Meyer Burger machines. Many of the employees had also worked in the solar industry during the first wave - and have now "come back with great enthusiasm", says Fritsche.

In the first construction phase, Meyer Burger plans to produce cells with a total capacity of 400 megawatts per year in Solar Valley. By 2023, this figure is expected to reach 1.2 gigawatts. This corresponds to almost a quarter of the total German capacity added in 2021 - a big step compared to the status quo, but it will probably not be possible without imports in the future.

The construction of another gigawatt cell factory is planned for 2024, ideally also in Solar Valley. "For cell production, you need a certain density of technological know-how," says production manager Fritsche. For this reason, he says, cell production should remain concentrated at one location. "The module factories, on the other hand, will be set up decentrally, close to the corresponding markets" - if only because of the higher transport costs of the voluminous modules. Meyer Burger's second module factory is currently being built in Arizona.