Optimal sizing of renewable energy storage: A comparative study of hydrogen and battery system considering degradation and seasonal storage

TL;DR

This study compares hydrogen and battery energy storage systems for renewable energy, optimizing their size and operation using a novel algorithm, and finds batteries are more economically mature while hydrogen offers better long-term storage potential.

Contribution

It introduces a Multi-Objective Modified Firefly Algorithm for optimizing renewable energy storage systems, considering degradation and seasonal storage, with validation on real and synthetic cases.

Findings

MOMFA outperforms NSGA-II in accuracy and robustness.

Batteries show better economic performance currently.

Hydrogen storage offers superior long-term techno-economic benefits.

Abstract

Renewable energy storage (RES) is essential to address the intermittence issues of renewable energy systems, thereby enhancing the system stability and reliability. This study presents an optimisation study of sizing and operational strategy parameters of a grid-connected photovoltaic (PV)-hydrogen/battery systems using a Multi-Objective Modified Firefly Algorithm (MOMFA). An operational strategy that utilises the ability of hydrogen to store energy over a long time was also investigated. The proposed method was applied to a real-world distributed energy project located in the tropical climate zone. To further demonstrate the robustness and versatility of the method, another synthetic test case was examined for a location in the subtropical weather zone, which has a high seasonal mismatch. The performance of the proposed MOMFA method is compared with the NSGA-II method, which has been widely used to design renewable energy storage systems in the literature. The result shows that MOMFA is more accurate and robust than NSGA-II owing to the complex and dynamic nature of energy storage system. The optimisation results show that battery storage systems, as a mature technology, yield better economic performance than current hydrogen storage systems. However, it is proven that hydrogen storage systems provide better techno-economic performance and can be a viable long-term storage solution when high penetration of renewable energy is required. The study also proves that the proposed long-term operational strategy can lower component degradation, enhance efficiency, and increase the total economic performance of hydrogen storage systems. The findings of this study can support the implementation of energy storage systems for renewable energy.