Shimizu Construction Co., Ltd. in Japan has made significant strides in developing hydrogen safe storage technology in collaboration with the Industrial Technology Research Institute. This new technology allows for the installation of small hydrogen fuel cell power plants within downtown buildings, paving the way for the concept of 'urban power plants' across the city. By using special alloys made of iron or titanium, hydrogen can be safely absorbed and stored in these buildings, enabling efficient power generation through fuel cells with low carbon dioxide emissions. The technology has the potential to provide about 20% of a building's energy demand, supplementing existing eco-friendly energy sources like solar power. The initiative, with test operations already underway in some buildings, aims to revolutionize urban power generation and contribute to a more sustainable energy future in Japan.