Review of Current Risk Assessment Framework in Gaseous Hydrogen Refuelling Stations with Suggestions of Improvement based on New Perspectives in Risk
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During the energy evolution currently undertaken, hydrogen has emerged as a potential energy carrier among others in transportation sector. However, assuring safety of the relevant infrastructure is a prerequisite to the adoption of hydrogen as a day-to-day road fuel. This thesis reviews risk assessments in hydrogen storage and distribution infrastructure, focusing in specific in hydrogen refueling stations, and sets as ulterior goal to suggest a risk assessment framework for the design and operation of the latter. Traditional risk assessments with their limitations are reviewed. Focus is placed on recent perspectives in risk, combining the probability based thinking anticipated in traditional risk assessments with qualitative approaches. One such framework is introduced and its practical features summarized in strength of knowledge characterizations and consideration of surprises, are presented and further analyzed. Using a case study stressing the limitations of existent methodologies, reflected in ISO/TS 19880-1: 2016, a new approach while assessing risks in hydrogen refueling stations is suggested. That is the implementation of the new integrative framework. In the rationale of cautious thinking, it is suggested that risk evaluation and treatment, currently based in probabilistic RAC alone, is changed such that it also reflects on the strength of knowledge upon which those criteria are based. The operation of an exclusive hydrogen database is awaited to contribute to the characterization of the knowledge the overall analysis is based on, and therefore the knowledge supporting risk acceptance as well. The contribution of this type of database in hydrogen refueling station risk assessments can be summarized in two broad dimensions; enabling statistical calculations on one hand, and providing the risk analysts with valuable input for the strength of knowledge characterization and the surprise assessment on the other.