Making The Case For Tandem Cell Technology

• Arizona State University researchers believe silicon solar module technology is on its way out with theoretical efficiency limit in sight
• In a research paper, they explored economics of silicon-based tandem PV modules and how ready they are to compete in the solar market place
• The research indicates by 2020, tandem modules with 32% efficiency would cost three times more than silicon modules with 22% efficiency, but could produce electricity at the same cost
• The results are aimed at researchers to show them how much money they're allowed to spend in realizing the efficiency enhancements expected from tandems to be able to compete with traditional silicon cells

Silicon single junction solar module technology that's used rampantly for production is 'more than 90% of the way to its theoretical efficiency limit'. It is now time to look for new and better technologies, according to a research team at Arizona State University (ASU). The team suggest as a substitute a silicon-based tandem PV modules that, it believes, offers higher efficiency than present modules. In the paper, it explores the financial viability for high-efficiency tandem PV modules that can compete in the market place.

The paper Techno-economic viability of silicon-based tandem photovoltaic modules in the United Statesexploring this technology was published in Nature Energy journal. The authors say tandem modules stack complementary PV materials together to best absorb solar energy and exceed the efficiency of either constituent solar cell on its own.

According to the research, in 2020, tandem modules with 32% efficiency can cost more than three times than 22% efficient silicon modules for the US residential solar market in the best-case scenario, but are projected to produce electricity at the same cost.

"Our previous study defines the technological landscape of tandems; this study paints the economic landscape for these future solar technologies that are only now being created in labs," said ASU Assistant Research Professor Zhengshan Yu. "It tells researchers how much money they're allowed to spend in realizing the efficiency enhancements expected from tandems."

Recently, Belgian Research Institute IMEC achieved 27.1% power conversion efficiency for a 4-terminal perovskite/silicon tandem PV cell (see 27.1% Perovskite/Si Tandem Cell From IMEC).

Another research by scientists from EPFL and CSEM claimed 25.2% record efficiency for tandem solar cell based on silicon and perovskite. The two institutes believe their manufacturing technique could be directly integrated into existing production lines to lift efficiencies beyond 30% (see 25.2% Record For Si-Perovskite Cell).