Offshore Hydrogen Production via the PEM Electrolyser Coupled With the Reverse Osmosis System

Abstract

Offshore production of hydrogen using seawater reverse osmosis (SWRO) and proton exchange membrane (PEM) technologies offers a promising pathway for green hydrogen generation from renewable energy sources (RESs). Realising this potential requires the integration of the SWRO unit and PEM electrolyser into a single system, with precise modelling to address the variability of RESs. Nevertheless, there are limited studies in the literature that examine a coupled SWRO-PEM electrolyser model. Therefore, in this article, an integrated SWRO-PEM electrolyser model is developed, detailing the modelling steps for each component. The models are subsequently validated against experimental data and upscaled to reflect a realistic scenario. Finally, a straightforward control method for the SWRO unit based on the electrolyser operation is suggested. The PEM electrolyser model showed an average relative error of 0.66% in static operation and 3.93% in dynamic operation. Meanwhile, the SWRO unit demonstrated an average relative error of 3.64% for water quantity and 1.48% for water quality compared to experimental results at low total dissolved solids (TDS) values, and 2.74% and 0.13% for water quantity and quality, respectively, at seawater TDS levels. Also, the control method estimated the water demand of the electrolyser with an average error of 1.20%.