Developing Hydrogen Production Technology to Achieve Low-Cost Production Through the Utilization of Surplus Renewable Energy and Grid Stabilization for Stable and Large-Scale Supply of Green Hydrogen
Overview of a green hydrogen production system using a high-voltage self-excited power converter
To achieve a carbon-neutral society, it is anticipated that a large amount of hydrogen will be needed as a substitute for existing fossil fuels. Hitachi aims to ensure a stable and large-scale supply of affordable green hydrogen by utilizing surplus renewable energy and providing services that stabilize power quality. This technology operates multi-connected water electrolysis stacks with a voltage sourced converter and performs condition diagnosis and degradation prediction of the connected water electrolysis stacks based on models, meeting the expected increase in demand for green hydrogen.
Amid the intensification of natural disasters believed to be caused by global warming worldwide, there is an urgent need to achieve a carbon-neutral society. The use of green hydrogen, derived from renewable energy, is being considered for industries where electrification is difficult and the use of fossil fuels as fuel or raw materials is unavoidable. However, green hydrogen is more expensive compared to fossil fuels, and the challenge in promoting green hydrogen lies in ensuring a stable and large-scale supply of low-cost green hydrogen.
Therefore, Hitachi proposes a green hydrogen production system that operates multi-connected water electrolysis stacks using the voltage sourced converter. This system operates the water electrolysis stacks with the voltage sourced converter that can supply services to stabilize the power grid while minimizing power waveform distortion during AC-DC conversion. By eliminating the equipment needed to compensate for power waveform distortion required by line commutated converter and providing services to stabilize power quality, this system achieves low-cost green hydrogen production. Additionally, to improve the reliability of the multi-connected water electrolysis system, it diagnoses the condition of individual water electrolysis stacks and implements degradation suppression operation through model-based control, thereby enhancing the operational rate of the water electrolysis system.
Hitachi contributes to the realization of a carbon-neutral society by utilizing its expertise in the voltage sourced converter and model-based control of water electrolysis stacks to develop a green hydrogen production system that ensures a stable and large-scale supply of low-cost green hydrogen.
