ALKALINE WATER ELECTROLYSIS FOR HYDROGEN PRODUCTION IN HIGH-IRRADIANCE REGIONS: STATE OF THE ART, EXPERIMENTAL EVIDENCE, AND PROSPECTS FOR UZBEKISTAN

Abstract

The combination of falling photovoltaic costs and rising policy pressure on carbon-intensive hydrogen production has created a compelling economic and environmental case for solar-powered alkaline water electrolysis (AEL). This review synthesises experimental data from four peer-reviewed publications produced at Andijan State Technical Institute (ASTI) [3–6] alongside seventeen international studies to examine the state of knowledge on electrolyte chemistry, electrode materials, and photovoltaic power integration. The ASTI dataset covers a 5-order-of-magnitude range of current density (3 mA cm⁻² to 500 mA cm⁻²), two electrode substrates (316L stainless steel and Ni-Mo alloy), and both direct and MPPT-mediated PV coupling. Across this parameter space, three design principles emerge as robust: (i) 30 wt% KOH at 60–80°C maximises ionic conductivity and electrode durability; (ii) the anode is the primary energy bottleneck on bare 316L, contributing 45% of total voltage loss and representing the highest-return upgrade target; and (iii) MPPT control captures 12–24% additional solar energy relative to direct coupling. Applying these principles to the Andijan solar resource, a 5 kW PV system can yield 160–180 kg of emission-free hydrogen per year at a levelised cost of $5–8 kg⁻¹, with a clear technical roadmap to below $5 kg⁻¹ through electrode coating and current density scaling.