: The transition to a 100% renewable energy mix is a real challenge in islanded Microgrids, which are traditionally equipped with diesel generators to ensure a reliable electricity supply. The solution can include introducing long-term seasonal energy storage in the form of hydrogen, coupled with short-term battery storage to ensure the quality and reliability of electricity supply while limiting the cost. For this purpose, our study consisted of setting up and developing various energy management strategies applied to these HESS microgrids and evaluating them. These strategies can be based on simple rules, predictive methods, or stochastic dynamic programming. We have implemented 2 rules-based strategies in the open-source sizing optimization tool Microgrids.jl . We present the adopted modeling approach, a review of the advantages and drawbacks of these 2 strategies, and their performance.