Japan bets on ultrathin solar panels to promote clean energy growth
At Expo 2025 Osaka, Japan is presenting an innovative advancement in solar technology — positioned not within a pavilion, but atop the curved roof of a 250-metre bus terminal. The installation, featuring more than 250 ultrathin perovskite solar panels, exemplifies Tokyo’s strategic initiative to spearhead the forthcoming phase of solar power innovation, diminish dependence on Chinese imports, and develop novel applications for urban solar deployment. Takayuki Taenaka, an official at Japan’s Ministry of Economy, Trade and Industry, stated that the new technology presents several advantages. “It’s like killing three birds with one stone,” he remarked.
Perovskite solar panels are a type of photovoltaic technology that utilizes a perovskite-structured compound as the light-harvesting active layer. These materials have garnered attention due to their potential for high efficiency and low production costs compared to traditional silicon-based solar cells. Perovskite panels, named for their distinctive crystal structure, consist of chemical compounds arranged in layers that are merely millimetres thick. The flexible, film-like panels exhibit power efficiency comparable to traditional polysilicon panels, yet they are 20 times thinner and 10 times lighter. Their adaptability facilitates installation on surfaces that are not conducive to rigid panels, including windows, walls, or rooftops that cannot bear substantial weight. This positions them favorably for nations characterized by high population density and substantial infrastructure, such as Japan.
Japan currently holds a leading position among major economies in terms of installed solar capacity per square kilometre of flat land. However, the mountainous geography constrains the potential for large-scale solar farms. Tokyo has set a target to produce as much as 29 percent of its electricity from solar energy by FY40, a significant increase from the current level of under 10 percent, through the implementation of perovskite panels on urban surfaces. Implementing these panels on walls, glass windows, and other vertical surfaces has the potential to transform urban landscapes into decentralized solar farms.
Despite the fact that perovskite solar technology was identified merely in 2009, it is progressing at an impressive pace. Sekisui Chemical, the developer of the panels for Expo 2025, intends to initiate commercial shipments by the conclusion of this fiscal year. Full-scale production is projected for FY27. Futoshi Kamiwaki, president of Sekisui Solarfilm—a subsidiary established to enhance product scalability—asserted that perovskite panels possess the capability to exceed traditional solar cells in terms of energy efficiency.
Conventional silicon solar cells generally achieve an efficiency of 20 percent. Sekisui’s perovskite panels have reached a field efficiency of 15 percent. However, in controlled laboratory settings, the technology has achieved nearly 30 percent, as noted by Kamiwaki. This commitment has drawn the interest of over a dozen participants, including significant industry leaders such as Panasonic and Kaneka, who are investigating the incorporation of perovskite cells into window glass and various construction materials. This wave of innovation is anticipated to bolster Japan’s objective of producing 20 gigawatts (GW) of electricity from next-generation solar technologies, including perovskite panels, by 2040. This output would be comparable to the energy produced by around 20 nuclear power plants, marking a substantial progression towards the nation’s energy independence and sustainability objectives.
