The world's growing population, expanding economies, and rapid technological progress have intensified the search for sustainable energy, making green hydrogen produced by renewable-powered water electrolysis a promising alternative to fossil fuels. This research examines the performance and cost of a green hydrogen production system that utilizes dual solar energy conversion methods to power an alkaline water electrolyzer (AWE) using TRNSYS software. Three system design configurations were analyzed under various climatic conditions across Egypt, including Cairo, El-Arish, Mersa-Matruh, Assiut, and Aswan. The first configuration (S.1) integrates a photovoltaic (PV) array with AWE. The second (S.2) adds an evacuated-tube solar collector to harness thermal energy, while the third (S.3) further incorporates a solar thermal storage subsystem to enhance stability and efficiency. The system configurations were evaluated daily, monthly, and annually. Daily and monthly analyses focused on Assiut, while annual assessments covered all five cities. Additionally, the AWE operating temperature, which ranged from 50 °C to 90 °C, was analyzed for its impact on performance metrics. Finally, an economic feasibility study was conducted for the three configurations for the five cities. Model validation showed strong agreement with experimental data from the literature. Results indicate that increasing the AWE temperature enhances hydrogen production efficiency and reduces energy consumption. On a daily scale, S.2 achieved the best performance on a spring day, driven by low PV module temperatures and optimal solar geometry, reaching an AWE operating temperature of 103.62 °C, a hydrogen production rate of 0.547 kg/h, and a total daily yield of 3.876 kg. The summer day showed the most significant relative improvement, with S.2 producing 5.5% more hydrogen than S.1 due to effective solar thermal integration. The monthly analysis revealed that S.3 achieved the highest hydrogen and oxygen productivity, primarily because it can store and reuse thermal energy for continuous water preheating. Annually, S.3 achieved superior performance, increasing hydrogen generation by 7.71%, improving efficiency by 4.68%, and reducing the Levelized Cost of Hydrogen by 4.25%, reaching 2.48 $/kg in Aswan. These findings emphasize that integrating a solar thermal energy storage subsystem improves the overall performance-cost of the solar-to-hydrogen generation system.