Exergy assessment of hydrogen production by oscillating water column wave energy converter

This paper deals with the performance of a Proton Exchange Membrane Electrolyzer powered by an off-shore Oscillating Water Column (OWC), focusing on the sustainability assessment of the electrolyzer through exergy analysis. Exergy efficiency of the electrolyzer is revealed to be related to energy output from the OWC device, which depends on its design scale. The study is supported by both experimental model of a simple off-shore OWC set-up and experimental PEM electrolyzer model, combined with a theoretical approach. Results show that exergy efficiency of the electrolyzer and overall renewability of the process decreases when OWC size scale increases, being the maximum exergy efficiency 60 . 59 , % , and the maximum renewability index 1.54. Higher renewability index and exergy efficiency values are obtained when the OWC diameter chamber is around ≲ 1 m , although OWC size may affect the value of the Levelized Cost of hydrogen production. • The lower the OWC scale factor, the higher the exergy efficiency for PEM electrolyzer. • The process is environmentally favourable when OWC diameter is lower than 1 metre. • Maximum exergy efficiency is 0.6059, and maximum renewability index is 1.54. • Minimum renewability index obtained is higher than 0.37, higher than coal plants. • Exergy efficiency for OWC-PEM electrolyzer coupling is around 30 ∼ 60%.