Nearly a decade after US production of silicon wafers for solar panels ceased, several companies have announced plans to revive wafer manufacturing in the country. Some hope new technologies will reduce the US solar industry’s reliance on China.
In January, NexWafe announced it may build a 6 GW wafer plant in the US. CubicPV announced last year that it secured commitments for $100 million to fund a 10 GW wafer facility in the US. And Qcells says it’s on track to open an 8.4 GW wafer facility in Georgia by the end of 2024.
The supply chain for silicon solar panels begins by refining quartz into rods of polysilicon, a nearly pure silicon with a multicrystalline structure. The polysilicon rods are then reformed into ingots with a single crystal structure, sliced into thin wafers, and treated with chemicals to make solar cells.
Companies in the US have made polysilicon and solar panels for years, but US wafer plants closed because they couldn’t compete with large-scale Chinese factories, according to a US Department of Energy report.
NexWafe is hoping its new manufacturing process will be more efficient than methods used in Chinese facilities. Instead of sawing micrometer-thin slices of silicon from an ingot, NexWafe deposits chlorosilane gas onto a template. The template has a top layer of perforated silicon that allows the company to detach the newly formed wafers.
Jonathan Pickering, NexWafe’s vice president of business development for North America, says producing polysilicon and ingots requires huge amounts of energy, and the sawing process wastes lots of material. He argues that skipping those steps will make NexWafe’s process cheaper. “We’re not going to out-scale the great work that’s been done in China,” Pickering says. “The way we’re going to win … is to drive a higher efficiency, higher performance, and find innovative ways to take cost out.”
Johannes Bernreuter, founder of the solar materials intelligence firm Bernreuter Research, warns that NexWafe still has a long way to go. The company only started building a 250 MW production line in Germany last year. “They still have to provide proof of viability on an industrial scale,” he says.
CubicPV is developing a process that forms wafers directly from molten silicon, and the firm says it should be cheaper and less energy-intensive than methods used in China. But CubicPV has yet to scale-up the process and will use conventional manufacturing methods at its planned US facility.
In Georgia, Qcells has already made significant progress on the construction of a wafer facility that will use conventional technology.
Bernreuter says these projects could add up to a respectable amount of wafer capacity for the US. “Wafers are the most important part of the supply chain to establish outside of China,” he says. “Keep your fingers crossed that it will work out.”