On the use of the ALARP principle for hydrogen systems

Hydrogen systems are increasingly promoted as an important part of the energy transition, yet the development and operation of these systems are associated with significant uncertainties and safety concerns. The ALARP principle, which states that risk should be reduced to a level äs low as reasonably practicable", is commonly referred to in this context. However, there is a lack of clarity and consistency when it comes to how the principle should be operationalized. In the present paper, we present an overview of how ALARP is currently understood and applied in relation to risk assessment and management of hydrogen systems. Drawing on issues previously identified in the broader ALARP literature, we highlight two issues that are of particular relevance for hydrogen systems: (i) assessments are performed at the component rather than system level, risking disproportional outcomes, and (ii) it provides little guidance for evaluating the suitability of risk-reducing measures over time. These issues are discussed in relation to a layered ALARP approach, where the operationalization of ALARP includes judgments on uncertainties, robustness, and broader management concerns. To illustrate the discussion, we use two cases related to the hydrogen context. The paper assesses the extent to which the alternative approach addresses the specified issues. The aim is to provide new insights into the operationalisation of ALARP and its role as risk-informed decision support in hydrogen risk management.

Keywords: ALARP, risk management, hydrogen.