Qcells plans gigawatt-scale factory for next-generation tandem solar panels by 2029

Qcells, one of the largest solar manufacturers operating in the United States, plans to open a gigawatt-scale factory in 2029 to mass-produce tandem solar panels, which layer perovskite crystals on top of conventional silicon cells.

Tandem cells convert sunlight to electricity far more efficiently than silicon alone and have set lab records, but they have degraded too quickly in real-world conditions. No company yet mass-produces them with a warranty comparable to conventional panels.

Qcells, owned by South Korea's Hanwha, has developed tandem cells since 2016 and runs a 40-megawatt pilot line in South Korea that produces full-size panels. In 2024, an independent body confirmed 28.6% efficiency for one of its standard-size tandem cells, compared with about 24% for today's high-performance panels. In July, the company said its tandem panel passed quality tests set by UL and the International Electrotechnical Commission (IEC).

"We're not a startup, unlike a lot of the Western tandem developers," Danielle Merfeld, the company's global chief technology officer, told Canary Media. "We don't need to raise money."

The factory's location has not been decided, though a company presentation in Seoul last week appeared to point to Jincheon, South Korea. Rivals are also moving: China's GCL said it opened a 1-gigawatt plant last year, and U.S. startup Tandem PV is targeting 2028 for a gigawatt-scale factory. Qcells declined to share its perovskite recipe or early field degradation data.

This brief is based on reporting by Julian Spector, published Oct. 13, 2026, in Canary Media. Read the original: https://www.canarymedia.com/articles/solar/qcells-aims-to-build-worlds-first-big-factory-for-next-gen-tandem-solar