An optimization model was developed using regional weather data, including solar irradiance and temperature, to determine the optimal size for a green hydrogen production plant. The design of an optimal plant size will play a crucial role in assisting the government and companies in their investment decisions regarding water electrolysis plants by ensuring both economic feasibility and productivity.

Mr. Joungho Park and researchers at the Energy AI and Computational Science Laboratory of the Korea Institute of Energy Research (KIER), led by President Yi Chang-keun, have developed an optimization model and framework to ensure the economic feasibility and efficiency of green hydrogen production using solar power. This method provides a creative solution to reduce the cost of hydrogen production while maximizing the utilization of solar energy. The model will play an important role in ensuring the economic viability of green hydrogen production.

Forecasts from the IEA and MarketsandMarkets indicate a significant increase in the hydrogen production market, estimated to grow from $129.6 billion in 2020 to $201.4 billion in 2025. In line with this, the global scale of water electrolysis plants is expected to grow by 86% per year through 2030. Renewable energy based green hydrogen production is at the forefront of the rapidly expanding global hydrogen production market.

With this forecast, KIER researchers led by Mr. Joungho Park have formulated a comprehensive optimization model for the production of solar-powered green hydrogen. This approach will support decision making for investment and operation of related facilities. This model has been validated by its successful application in the USA, China and Australia, where green hydrogen will be commercialized in the near future. Factors such as the levelized cost of hydrogen, the amount, and the capacity factor of electrolyser have been carefully evaluated.

Based on local irradiation and temperature data, the system model determines the amount of solar power and green hydrogen that can be generated. A multi-objective optimization model is used to determine the optimal size of the water electrolysis system and battery. An analysis of the trade-offs is performed, taking into account economic feasibility, production volume, and utilization. Through this approach, a customized system design can be created to meet the user's specific objectives and priorities.

To achieve economic feasibility, the water electrolysis capacity must be 60% of the solar power capacity, regardless of the amount of sunlight in the area. To increase hydrogen production, it is necessary to install batteries to store electricity during peak periods. However, in order to maintain economic viability, the battery capacity must be kept to a minimum.

The research leader, Mr. Joungho Park, explains that this study shows the optimal size for a solar-powered green hydrogen system, which is on the verge of becoming economically and productively feasible. According to him, the optimal model is crucial for developing a successful system for solar-powered green hydrogen initiatives undertaken by both government agencies and companies in and around the country.

The study, conducted in collaboration with Jay H. Lee, a professor at the University of Southern California, USA, was published on 3 November 2023 in the journal of ‘Energy Conversion and Management and it is now accessible online.