The purpose of this article is to describe a new concept which is social comprehensive risk to discuss safety assessment of technological systems, and conducts a case study on safety assessment of hydrogen energy carrier. The concept mainly consists of three stages: workplace risk, societal risk, and social comprehensive risk. We introduce a framework for societal comprehensive risk assessment, and conduct safety assessment of hydrogen fueling stations. In addition, we outline our findings about qualitative risk assessments of hybrid hydrogen and gasoline fueling stations, detailed consequences analyses of pool fires and hydrogen and leakage, and the commnon causes of incidents and accidents involving hydrogen fueling stations. Two problems are pointed out: One is to lacks a quantitative risk analysis such as individual risk and societal risk, and the other is to scarcely consider a risk treatment such as emergency response and recovery. Finally, a social comprehensive risk analysis is summarized from additional two approaches consisting social value evaluation and life cycle assessment. We offer a new direction to safety assessment of hydrogen fueling stations based on the concept of societal comprehensive risk.
Organic hydride is considered as one of energy of hydrogen. Hydrogen supplying technology based on organic hydride is now developing in Japan. However, there is no existing study for considering safety of a hydrogen refueling station using organic hydride. The aim of this study is to identify and quantify the human individual risk related to hydrogen explosions and chemical release during the operation of a hydrogen refueling station using organic hydride. As the result, mortality risk by explosion and acute effect was under 10-6 year-1 which is a negligible risk level of concern. However, mortality risk by heat radiation was above 10-3 year-1 which requires a next step to conduct risk assessment in detail.
In recent years, hydrogen that is noticed as fuel cell vehicles has already been used as industrial gas in various fields.
However, hydrogen has the lowest density among all gases, and it is easy to leak to the outside. Furthermore, it is concerned that explosion and fire are likely to occur after leaking hydrogen compared to other gases, as hydrogen has a wide explosion range (4 to 75 vol%) in air and low minimum ignition energy (about 0.02 mJ).
So we focused on hydrogen and showed statistics and analysis of high pressure gas accident of hydrogen, and took notes for future measures.
This paper describes that safety evaluation test methods and existing technologies focusing on safety measures of hydrogen cylinders in case of fire of fuel cell vehicles are becoming safer technical standards based on lessons learned from the compressed natural gas vehicle (CNGV) accidents caused by defects in the pressure relief device, which is an important device to prevent rupture of the cylinder in case of fire. In addition, to protect the cylinder from local flame, techniques to improve the heat resistance of the cylinder is introduced.
Safety management for flammable hydrogen gas at Ito campus, Kyushu University is introduced. Since various research projects related hydrogen energy have been going on, for example, the safety infrastructure with hydrogen supply and exhaust systems using sensors and alarms is installed. Besides safety control in terms of facilities, International Research Center for Hydrogen Energy gives an annual training program on hydrogen safety for students, faculty members, and other university staffs. As another tool to develop a safety environment for experiments, submission of “near-miss report” is obligated when a minor accident occurs. Based on the collection of “near-miss report” for 10 years, tendencies of minor accidents and safety measures are analyzed and discussed in detail.
The impacts of hydrogen energy introduction on national wealth outflow are evaluated in the study group of CO2-free hydrogen dissemination scenario hosted by IAE.
They are compared with LNG chains not for direct comparison but just for reference because LNG chains are matured but CO2-free hydrogen chains are expected in the future.
Liquefied hydrogen derived from Australian lignite is adopted as a hydrogen energy career because the results of feasibility studies are publicized.
If the liquefied hydrogen is imported in the same amount of heat with LNG, imported amount of money is increased for hydrogen, but domestic reflux money is increased by that increased amount for hydrogen because of the same level of overseas outflow money.
Imported hydrogen, accordingly leads to the creation of new industries and the growth of domestic job opportunities.