To clarify the role of hydrogen and vital technological and infrastructural development, an imported hydrogen core, a synthetic fuel core and a domestic hydrogen core scenarios have been discussed using techno-economic analysis of carbon neutral energy systems of Japan. A significant amount of domestic renewable energies will be introduced in all scenarios, and even the energy self-sufficiency of the imported hydrogen core scenario will reach 45%, while the current energy self-sufficiency is less than 10%. To import hydrogen, hydrogen infrastructure is very important for the Tokyo, Chubu, Kansai, and Chugoku areas where there are large energy demand. If less expensive hydrogen transport such as widespread of hydrogen pipeline infrastructure is realized, consumer sector will select distributed generation systems such as fuel cell cogeneration, otherwise, all domestic energy transmission will use electricity if hydrogen transportation is expensive. To select a fuel synthesis core scenario, the cost of fuel synthesis including the production of carbon-neutral CO₂ must be lower than the cost of hydrogen storage and transportation. The investment to install infrastructure for the synthesis fuel core scenario is the most inexpensive of these scenarios. The energy price of the imported core scenario will be the cheapest, and the domestic hydrogen core scenario will be the best for energy security. To ensure economic rationality and energy security, it is necessary to choose a hydrogen core scenario that utilizes both international and domestic renewable energies.

Establishing the safety of hydrogen infrastructures and fuel cell systems against the danger of hydrogen leakage will encourage the economics of hydrogen, lowering the cost of related systems, and safe operation of the system will appeal to the public. Hydrogen related facilities may be required to have the ability to detect hydrogen concentrations before a specified concentration of hydrogen or a fraction of flammable limit is reached, in order to allow for single and/or multilevel safety operations. The ISO standard will provide requirements for stationary hydrogen detection apparatus, covering both performance requirements and test methods. In this article, the hydrogen sensors and their applications are reviewed and the details of ISO 26142 “hydrogen detection apparatus” including the scope, history, and current activity of standardization are introduced.

Currently, a society that utilizes hydrogen is being built to achieve carbon neutrality by 2050, wherein liquid hydrogen is expected to serve as a significant energy carrier. However, challenges remain; particularly regarding the efficient utilization of cold heat. To address this issue, we propose using liquid hydrogen as a refrigerant in high-temperature superconducting (HTS) generators. The hydrogen gas evaporated from a HTS generator can be harnessed for power generation in a hydrogen gas turbine after cooling the HTS field coils. Presently, the liquid hydrogen test facility at JAXA's Noshiro Rocket Testing Center is employed to evaluate the energization characteristics of HTS coils cooled using liquid hydrogen and to build a safety record for liquid hydrogen testing. Furthermore, a 10 kW-class liquid hydrogen-cooled HTS generator is demonstrated under NEDO's Leading Research Program. The goal is to develop a new HTS power system that employs liquid hydrogen as a refrigerant.

While the use of Hydrogen is promoted to realize a decarbonized society, the most is getting electrical energy from Fuel Cell. However, decarbonized for “thermal energy” that industrial sector and heating in cold regions cannot be covered by electrical energy only, shall be advanced. Our company has developed and recently launched Hydrogen firing Large Capacity Once- Through Boiler “Ifrit” which produce thermal energy form Hydrogen fuel.

The equilibrium plateau pressure of hydrogen-absorbing alloys changes depending on the temperature. Metal hydride actuator applies this pressure difference upon heating as a pressure source to drive the actuator. This characteristic of the hydrogen-absorbing alloys allows the actuator to drive without electricity if a heat source is available. In addition, there is neither driving noise or vibration because the driving force is based on a chemical reaction. Furthermore, hydrogen-absorbing alloys are capable of desorbing (absorbing) hydrogen gas approximately 1000 times of their own volume upon heating, which offer good power-to-weight ratios. Thus, metal hydride actuator has a potential to realize user-friendly characteristics in daily life space, which is difficult to achieve with other types of actuators. We introduce our previous research on metal hydride actuator in this paper. First, we overview the properties of hydrogen-absorbing alloys, and their effective use as a pressure source of metal hydride actuator. Then, we describe application of soft, and flexible structure as an end effector of metal hydride actuator. Finally, our latest research on jack-up tool as a rescue device is summarized as an example of development of soft metal hydride actuator.

Hydrogen is considered to be a fuel that does not emit CO₂ during its use. However, CO₂ is often generated during the production process. This is an important issue that cannot be ignored as countries actively promote the widespread use of hydrogen. In the case of electric vehicles (EVs), for example, the CO₂ emissions (coefficients) associated with the electricity used are crucial. Fuel cell buses (FC buses) face similar challenges. Although they produce no CO₂ during operation, the CO₂ emissions from their manufacture cannot be ignored. As the use of hydrogen continues to expand in power generation, industry and other sectors, understanding the specific amount of CO₂ generated - particularly throughout the supply chain from production to use - becomes essential. With this in mind, this article aims to explain the concept of 'carbon intensity', which includes CO₂ emissions not only during production, but also throughout the life cycle of hydrogen use.