(439d) Integrated Co-Optimization of a Water-Power-Hydrogen System Using Renewable Energy Conversion

As the energy transition evolves, hydrogen is considered an alternative energy carrier [1]. However, traditional hydrogen production processes, like the steam reforming process, involve carbon dioxide emissions. Green hydrogen is a potential alternative to address the emissions issue since it is an endogenous near zero-carbon process by using renewable energy and electrochemical water-splitting technology. However, due to the cost and efficiency of commercial electrolyzers and the uncertainty and variability of renewable energy, the price of green hydrogen is currently not competitive for worldwide usage. In this work, we propose a novel green hydrogen design and operational model integrating the operations of electrolyzer system with water desalination and renewable electricity generation. The model involves the capacity design of the proton exchange membrane (PEM) electrolyzer system, hydrogen storage, reverse osmosis desalination, water tanks, wind and photovoltaic power generation, concentrated solar power (CSP), and battery storage. In particular, the CSP plant is modeled considering details involving losses, startup, and shutdown operations. This technology set is appropriate for countries with high solar radiation and limited water availability. The model assumes an hourly resolution and one-year horizon to capture weather variability. Two types of hydrogen demand are considered: 1) local continuous demand at each hour and 2) a weekly or seasonal demand that represents, for example, international demand every period to be supplied to shipping vessels. The latter demand profile motivates the usage of hydrogen tank, desalinated water tank and thermal energy storage as buffers to take advantage of the variable renewable sources. The main objective is to minimize the levelized cost of hydrogen (LCOH) and determine the optimal capacities and operations of the technologies. Ultimately, the results can support decision-makers in designing and pursuing a sustainable and commercial multi-year plan for green hydrogen production. Case studies in the United States and Saudi Arabia indicate that the well-designed combination of all technologies can lead to an LCOH as low as 5 $/kg.

[1] Riera J.A., Lima R.M., Knio O.M., 2023. A review of hydrogen production and supply chain modeling and optimization. International Journal of Hydrogen Energy 48 (37), 13731–13755.