Japanese researchers are exploring a new method to produce green hydrogen that could revolutionize the energy transition. Currently, green hydrogen production is limited by the high amount of renewable energy required, making it costly. The new method being investigated by scientists at Shinshu University in Matsumoto involves using sunlight and a photocatalyst to efficiently separate hydrogen and oxygen in water, potentially reducing costs and making green hydrogen more accessible. The industry's interest in 'green hydrogen,' produced using renewable energy sources, is considered essential for combating climate change. However, only a minuscule fraction of hydrogen production worldwide is classified as green due to the cost implications. To address this challenge, the researchers are exploring a two-step excitation process that improves energy conversion efficiency and operates more effectively under natural sunlight. While some obstacles remain, such as finding durable materials and ensuring safe reactor operations, the successful operation of the proof-of-concept reactor under natural sunlight is a positive sign for the technology's future. If the efficiency of solar-to-chemical energy conversion can be enhanced to practical levels, it could lead to the development of mass production technology and large-scale plants, bringing Japan closer to realizing its vision of a 'hydrogen society.' Despite Japan's leadership in hydrogen fuel, concerns have been raised about the nation's overemphasis on this technology at the expense of other green energy solutions. If the cost of green hydrogen production can be lowered significantly, it could pave the way for a sustainable energy future where hydrogen plays a central role.