The role of power-to-X in hybrid renewable energy systems: A comprehensive review

The demographic growth and the irreversible decline of fossil fuel deposits argue for alternative resources to meet energy demand. The main challenge is to make renewable energy sources (RES) and hydrogen carriers work synergistically to minimise waste and increase sustainability. Hybrid renewable energy systems (HRES) tackle this task by integrating RES and other resources to provide energy. Recently, Power-to-X (P2X) has been gaining attention for its versatility in converting hydrogen into different energy carriers. This review provides a comprehensive overview of the HRES literature and the current state of the art, highlighting key features, analysis, and methods. Future research trends are discussed, emphasising the need to integrate other energy carriers, including hydrogen. A survey of the Power-to-X possible uses in HRESs is carried out, describing which Power-to-X technologies belong to HRES state-of-the-art. Power-to-X paths not yet explored are discussed, remarking the benefit and potential uses as a means to increase the reliability of the energy system of each HRES Power-to-X technology integration, highlighting the unexplored paths. In addition, future developments and gaps in the current state of the art according to HRES with Power-to-X are highlighted. Finally, recommendations on hybrid renewable energy systems, including Power-to-X, are highlighted by outlining future research areas. •HRESs scientific literature and current state-of-the-art.•HRES future research trends.•HRES with P2X state-of-the-art.•Current gaps and trends on P2X in HRES integration.