An operational resilience objective to integrate in capacity expension models for green hydrogen production through HRES

Abstract

Green hydrogen is an attractive energy vector due to its zero carbon emission in production and use, supporting transportation and power systems in a transition to cleaner energy worldwide. The production of green hydrogen has a fundamental challenge in resilience since renewable energy (RE) systems are subject to variability. Chile presents an important advantage for producing green hydrogen due to its favorable weather conditions, with solar and wind energy being dominant in the north and south of the country respectively. The nation has developed a hydrogen strategy that strives to convert Chile into a major global producer of green hydrogen worldwide, but due to the uncertain nature of RE systems, the variability of the energy supply must be dealt with, especially in off-grid systems. The present thesis develops a novel operational resilience objective function to be included in green hydrogen capacity expansion models. This function is constructed from external source fluctuations, internal converter failures, and the capacity of a dual storage system to provide a more reliable and flexible system. The novel objective functions capture the nuance of variability in the allocation of hydrogen production facilities in different geographical locations and mitigate the expected variability of the system through the storage capacity design in each plant. An illustrative case study in the Biobío region corroborates the objective function use, obtaining a more robust plant design with the same hydrogen equilibrium price as a purely economic model, implementing higher storage capacities and different expansion profiles that account for storage in a more strategic manner. The systems design also considers the specific variability present in each location, where different wind and solar energy sources capacities are established accordingly. Compared to the economic model, the multi-objective approach reduces the wind power installations by up to 51% due to their more unstable nature, compensating with the more stable solar source with an increased capacity of up to 23% depending on the location. The contrast of storage capacities is notable when the proposed objective function is incorporated, resulting in an increase of an order of magnitude in the hydrogen and battery storage capacity. In this case study, the design changes require an investment of $0.37 [USD] per kilogram of produced hydrogen to achieve a less variable and more robust system.