Japan is re-emerging in the solar cell market with innovative perovskite technology, known for its flexibility and efficiency. Set to showcase at the World Expo in Osaka, the country aims for a capacity of 20 gigawatts by 2040. While facing challenges in durability and cost against traditional silicon cells, Japanese companies are making strides in production and application, potentially transforming urban environments into solar power generators.
Japan’s Solar Revolution: The Rise of Perovskite Technology
China has long held the crown in the global solar cell market, but that wasn’t always the case. For many years, Japan, revered as Asia’s oldest industrial powerhouse, led the world in solar energy innovation. Now, with the introduction of a groundbreaking type of solar cell, Japan is setting its sights on reclaiming its former glory and a substantial share of the market.
These innovative solar cells, known as perovskite solar cells, stand out from traditional silicon-based cells due to their flexibility, lighter weight, and enhanced efficiency. Notably, the light transmittance of these cells can be adjusted depending on the technology employed. Although these cells are still in the prototype phase and require further development to enhance their lifespan, Japanese companies are eager to demonstrate their reliability for long-term use.
Ambitious Goals and Future Prospects
Japan will showcase its perovskite solar cells at the World Expo in Osaka this April, where two-meter-long panels will adorn the 250-meter-long roofs of the bus station, designed to charge storage batteries and illuminate the waiting areas.
This initial demonstration marks just the beginning of Japan’s ambitious plans. The Ministry of Economy, Trade and Industry aims to deploy perovskite solar cells with a total capacity of 20 gigawatts by 2040, which is comparable to the output of 20 conventional nuclear reactors. Currently, solar power contributes approximately 11 percent to Japan’s electricity mix.
With billions in government support, Japan is poised to dominate a burgeoning market that is attracting interest from numerous countries. In Germany’s Brandenburg region, British solar company Oxford PV has initiated production of tandem solar cells that merge perovskite with traditional silicon technology.
Research on perovskite solar cells is also gaining momentum in China and South Korea, thanks to their numerous advantages over existing technologies, such as being environmentally friendly and more efficient.
While traditional solar cells rely on silicon derived from quartz sand—a process that is energy-intensive and emits carbon dioxide—perovskite is composed of calcium and titanium oxide. This mineral can be sourced with significantly less energy and can be applied in thinner layers, offering a promising energy yield. Japanese researcher Atsushi Wakamiya from Kyoto University has reported energy conversion rates exceeding 25 percent in laboratory settings with small prototypes. Moreover, combining perovskite with other materials could potentially achieve conversion rates between 33 and 45 percent.
Isao Takasu, from Toshiba, one of the leading technology firms in Japan, emphasizes the ease of processing pure perovskite cells. They can be applied thinly to flexible surfaces or glass, which is particularly advantageous for Japan’s urban buildings where space for conventional solar plants is limited. “Traditional silicon solar cells are quite heavy and often unsuitable for many installation sites,” notes Takasu.
The lightweight nature of perovskite technology opens up new avenues for solar integration on rooftops of factories and sports facilities, allowing for the addition of solar modules to exterior walls, which could transform even high-rise buildings into solar power generators.
Japan’s ambitions in solar energy are also driven by industrial policy. The technology has its roots in Japanese research, with Tsutomu Miyasaka being a pioneer who discovered in 2006 that perovskite could effectively convert sunlight to electricity. This breakthrough has paved the way for further advancements in the field, as various companies race to bring perovskite solar cells to market.
However, achieving flawless application of the thin perovskite layer remains a challenge, as imperfections can lead to reduced efficiency. Toshiba’s innovative production method aims to coat large films in a single step, minimizing errors and reducing costs for mass production. Takasu reports that their films achieved an energy yield of 16.6 percent in 2022, a significant achievement for a relatively large prototype measuring over 700 square centimeters.
Meanwhile, Sekisui Chemical is exploring flexible solar models, having conducted field tests with small modules in 2023, eventually expanding to larger installations. The upcoming World Expo will serve as a significant platform for showcasing this technology on a larger scale.
Panasonic is also innovating with semi-transparent solar cell windows, applying the perovskite layer to glass panes used in liquid crystal displays. The initial opaque panels can be made transparent using a laser, enhancing their applicability in construction projects, although market readiness is still on the horizon.
Experts at Toshiba are targeting mass production by 2030, but several hurdles remain for widespread adoption. Key challenges include ensuring the durability and stability of the films and windows, with current lifespans for smaller formats around 10 years, while aiming for 25 years for extensive market introduction.
Cost remains a crucial factor as well; conventional solar cells are currently very affordable. Takasu notes that prices for crystalline silicon solar cells are low due to intense competition, particularly from China. Researchers are still working to predict the pricing for perovskite cells, which could ultimately prove to be less expensive due to lower energy requirements during production and potential for easier mass production through printing technologies.
Despite the challenges posed by China’s dominance in solar manufacturing, Japan continues to have companies focused on producing modules primarily for residential use, where consumers are often willing to invest more for added performance. Toshiba is determined to leverage this opportunity, blending technological advancements with competitive strategies to thrive in this dynamic market.