Impact of green hydrogen integration on the optimal sizing and cost of isolated PV–wind hybrid systems

Hybrid renewable energy systems, particularly wind–photovoltaic (PV) microgrids, are widely recognized as promising solutions for sustainable power generation. However, their economic performance is significantly affected by the high cost of energy storage elements, especially batteries, which are required to balance the intermittent nature of renewable sources. This challenge motivates the need for alternative strategies to mitigate the dependency on conventional storage systems. The main innovation of this work is the development of a unified techno-economic framework that comparatively evaluates the optimal sizing and techno-economic performance of five isolated PV–wind hybrid system configurations incorporating batteries, hydrogen production, fuel cells, and diesel backup under identical operating conditions. The framework further considers hydrogen as a revenue-generating energy carrier rather than solely an energy storage medium, enabling a comprehensive assessment of its impact on optimal system sizing and overall system cost. This paper proposes an effective approach to overcome the high cost associated with storage components by utilizing surplus renewable energy instead of relying solely on battery storage. During periods of excess generation-especially when wind and PV outputs coincide-the surplus energy is converted into hydrogen through electrolysis rather than being wasted. The produced hydrogen can be stored and later utilized via fuel cells or sold as a valuable energy carrier, thus improving the overall system economics without wasting the surplus renewable energy loss. Genetic Algorithm (GA) is employed to optimally size the system components under different operating scenarios. Five hybrid system configurations are optimized and comparatively analyzed to evaluate the effectiveness of the proposed framework. The results demonstrate that reducing reliance on battery storage while integrating hydrogen production significantly lowers the net present cost. A cost reduction of up to 78.5% is obtained under the considered assumptions, indicating the potential economic benefit of hydrogen integration.