A research team at the Korea Institute of Energy Research has demonstrated the effectiveness of a green hydrogen system in stabilizing renewable energy grids by managing the variability of solar and wind power. The study emphasizes the importance of green hydrogen, produced using renewable sources, in achieving goals of carbon neutrality and energy security. By utilizing Power-to-Gas technology, surplus renewable energy is converted into green hydrogen, addressing power grid instability and output restriction issues. The research team developed a model to determine the optimal scale of green hydrogen systems, providing economic feasibility and stability metrics such as System Levelized Cost of Electricity and Loss of Power Supply Probability. Simulation results showed that green hydrogen is most effective when solar and wind power are combined equally, offering economic efficiency and low power supply losses. This study, conducted in collaboration with the University of Southern California, highlights the significance of green hydrogen for energy transition strategies and decision-making processes in government and industry sectors.