Integrated Electrochemical Process Modelling and Techno-Economic Assessment of Micro-Mesh Alkaline Seawater Electrolysis for Green Hydrogen Production

Abstract

This study couples an experimentally calibrated electrochemical model with a techno-economic assessment of expanded nickel micro-mesh electrodes for alkaline electrolysis of seawater (M-SWELT). A zero-gap cell model with explicit thermodynamic, kinetic, bubble and ohmic terms is anchored to commercial alkaline performance, checked against published resistance measurements and calibrated to a like-for-like two-electrode comparison of micro-mesh and woven Ni-mesh cells in natural seawater with 5 M KOH. Because one operating point cannot separate kinetic from resistive contributions, the transferred voltage saving at 0.4 A cm⁻² and 80 °C is bounded at 20–187 mV (central 89 mV). The model is coupled to two seawater feed routes, reverse-osmosis (RO) desalination and direct feed with softening and a chloride bleed, and to a cost model of a 10 MW plant. The RO-fed micro-mesh plant reaches a levelised cost of hydrogen (LCOH) of £4.35 kg⁻¹, against £4.51 kg⁻¹ with woven mesh, and the micro-mesh breaks even at an electrode premium of up to £950 m⁻² (range £217–1,985 m⁻²). Even without chloride oxidation and with electrodes that last as long as the stacks, direct feed costs £4.95 kg⁻¹, because the chloride bleed discards KOH and forces a dilute electrolyte; crediting the chloride’s conductivity narrows the gap to RO feed without closing it, and short electrode life widens it. Across 10,000 Latin-hypercube Monte Carlo samples, the RO-fed micro-mesh plant averages £4.72 kg⁻¹ (P5–P95 £3.95–5.59 kg⁻¹); it is cheaper than woven mesh at equal electrode cost, and direct feed is dearer than RO feed, in every sample.