(313c) Incorporating Total Cost of Process Risk (TCPR) in the Design of Sustainable Hydrogen Economy

In recent times, hydrogen has garnered significant attention due to its versatile use as fuel, feedstock, and energy carrier with the highest energy content by weight. The demand for hydrogen in the United States is projected to reach more than 41 MT per year by 2050 [1]. However, there are concerns not only regarding the economic feasibility of large-scale hydrogen production, but also safety concerns as well. Hydrogen poses the potential to be a catastrophic hazard in part due to its low minimum ignition energy and wide flammability range [2]. Hydrogen can also easily dissolve into most metals, making hydrogen embrittlement of pipelines a major concern [3]. As such, it is increasingly important that safety considerations be included in the processing, transportation, storage, and usage of hydrogen. However, quantifying safety is a challenging problem especially at early design stages. To identify and assess process safety risks, typically a Hazard and Operability Analysis (HAZOP) is performed. However, at the design stage detailed information needed for a HAZOP might not be readily available [4]. Other techniques that can be used such as a risk matrix are qualitative or semi-quantitative in nature. These assessment techniques typically capture relative risk levels for a given process and are not often scalable.

In this work, we put forward “Total Cost of Process Risk (TCPR)” as a quantitative measure of overall process safety risks in the production, storage, transportation, and usage of hydrogen. Next, we incorporate TCPR in designing optimal hydrogen-based energy supply chain to meet variable energy demands from renewable sources with intermittent availability at geographically different locations. Hazards are initially identified using a safety index. The indices are then used to calculate a damage radius for a potential accident and estimate the costs associated with process safety risks. These risks include the cost of production loss, cost of asset loss, cost of health loss, and risk transfer premiums [5]. We focus on the TCPR associated with the production of hydrogen at the electrolyzer, the transportation of hydrogen, the storage of hydrogen, and the processing of hydrogen at fueling stations. We demonstrate how the TCPR scales at different capacities for each aspect of the hydrogen economy. Finally with the risk identified and quantified, the cost of mitigation by implementing safety systems is evaluated.

References:

[1] Ruth, M.F., Jadun, P., Gilroy, N., Connelly, E., Boardman, R., Simon, A.J., Elgowainy, A., Zuboy, J. 2020. The Technical and Economic Potential of H2@Scale Concept within the United States. National Renewable Energy Laboratory (NREL).

[2] Organisation for Economic Co-operation and Development. 2023. Risk-based Regulatory Design for the Safe Use of Hydrogen, OECD Publishing, Paris.

[3] Barrera, O., Bombac, D., Chen, Y., Daff, T.D., Galindo-Nava, E., Gong, P., Haley, D., Horton, R., Katzarov, I., Kermode, J.R., Liverani, C., Stopher, M., Sweeney, F. 2018. Understanding and mitigating hydrogen embrittlement of steels: a review of experimental, modeling and design progress from atomistic to continuum. Journal of Materials Science. 53, pp. 6251 – 6290.

[4] Roy, N., Eljack, F., Jimenez-Gutierrez, A., Zhang, B., Thiruvenkataswamy, P., El-Halwagi, M.M., Mannan, M.S. 2016. A review of safety indices for process design. Current Opinion in Chemical Engineering. 14, pp. 42 – 48.

[5] Khan, F.I., Amyotte, P.R. 2005. I2SI: A comprehensive quantitative tool for inherent safety and cost evaluation. Journal of Loss Prevention in the Process Industries. 18(4 – 6), pp. 310 – 326.