The use of solar energy for electricity generation and use of this electricity for hydrogen production by alkaline water electrolysis promises to be a truly sustainable scheme for the postulated hydrogen economy. This work addresses the design of a standalone solar photovoltaic (PV) energy system that meets the energy requirements of the electrolysis process, followed by the performance analysis under different environmental conditions. Energy requirement for electrolysis depends on the hydrogen production rate desired and the operating conditions of the electrolysis cell and it has been predicted from an essentially thermodynamic analysis. Mean solar irradiation data is estimated from location specific meteorological data. The current-voltage output characteristics of the solar modules have been predicted as function of the solar irradiation using the five parameter, single diode model of a solar panel and they have been linked to the production rates of hydrogen. The module behaviour and its thermodynamic and conversion efficiencies have also been predicted for actual operating conditions. Thus a step-by-step simplified approach for the preliminary PV power system design and analysis for an electrolysis based hydrogen production unit has been presented in this study. (C) 2016 Elsevier Ltd. All rights reserved.