Investigations of an off-grid system based on a hybrid photovoltaic and wind turbine system with integrated hydrogen production located in PolandMagdalena Dudek, Andrzej Raźniak, Umar Majeed Sada, Iliya Iliev, Jarosław Markowski and Piotr DudekE3S Web Conf., 638 (2025) 01001DOI: https://doi.org/10.1051/e3sconf/202563801001