TOKYO -- Japan plans to provide about 100 billion yen ($636 million) over four years to support mass production of next-generation flexible perovskite solar cells, Nikkei has learned, bolstering the commercialization of a technology in which the country has strengths.

The Ministry of Economy, Trade and Industry is expected to soon select Ricoh and Choshu Industry for the subsidies, which are expected to total 100 billion yen through fiscal 2029.

The companies will invest at least as much themselves. The combined public and private funding will be used to build mass production facilities.

Ricoh is developing thin, flexible film-type solar cells using inkjet technology originally employed in printers. The process can reduce costs compared with existing laser-based manufacturing methods, according to the company.

Choshu Industry is focusing on tandem solar cells that layer perovskite cells on top of conventional silicon solar panels.

Mass production of perovskite solar cells in Japan is set to begin in 2027 by a Sekisui Chemical subsidiary that will make film-type cells with support from earlier subsidies. Panasonic Holdings plans to begin mass production of glass-based perovskite cells suitable for windows in 2029.

Japan once led the world in silicon solar panels but was overtaken by lower-cost Chinese competitors. Perovskite technology, which originated in Japan, is seen as a potential vehicle for regaining competitiveness.

Japan ranks second in the world, behind Chile, in iodine production, a key raw material for perovskite cells. This will make it easier to establish domestic supply chains and reduce economic security risks. Japanese companies can also leverage their strengths in such areas as high-performance films and thin-film processing technologies.

Concerns over the unchecked development of large-scale solar farms using silicon panels have also increased interest in perovskite cells. Their lightweight design makes them easier to install on existing buildings, raising expectations that they could play a significant role in decarbonization efforts.

Competition in the sector is intensifying. Chinese manufacturers have taken an early lead in glass-type cells, which are easier to mass-produce, and are also making progress in the film-type technology that Japanese companies are emphasizing.

China surpassed Japan in 2023 to become the world leader in perovskite patent applications valid in at least two countries, according to a Nikkei survey conducted through a research firm.

Japan plans to establish a regulatory framework in fiscal 2026 to prepare for mass production, revising rules that now require at least 25% of industrial sites to be dedicated to green space or environmental facilities. The new rules would allow compliance to be measured based on visible surface area from the front rather than from above, making it easier for wall-mounted perovskite installations to qualify.

The Fire and Disaster Management Agency will also revise guidelines so that perovskite panels can be installed at such locations as gas stations and automobile plants without protective cover glass.

Perovskite solar cells are one of the 17 priority sectors in Prime Minister Sanae Takaichi's growth strategy. The government intends to incorporate commercialization efforts into an energy-sector decarbonization strategy due out in late 2026.

To help spur adoption, the government plans to install perovskite solar cells at central government ministries, regional government offices, and Self-Defense Force bases and camps. On Oct. 19, the economy, land and environment ministries jointly called on local governments to look into installing the technology at public buildings and infrastructure facilities.