Inl. J. Hydrqen Energy, Vol. 18, No. 12, pp. 995-1000, 1993. Printed in Great Britain. 036C-3199/93 $6.00 + 0.00 Pergamon Press Ltd. 0 1993 International Association for Hydrogen Energy. zyxwvu SOLAR HYDROGEN PRODUCTION: A SPANISH EXPERIENCE A. G. GARCiA-CoNDi?* and F. ROSA~ * Instituto National de Ttcnica Aeroespacial (INTA), Ctra. de Ajalvir Km. 4.7, 28850 Torrejon de Ardoz. Madrid, Spain t lnstttuto National de ‘l‘ecmca Aeroespacial (INTA), Ctra. Mazagon-Matalascafias Km. 27.2, 21130 Mazagon, Huelva, Spain zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQP (Received for publication 15 M arch 1993) Abstract-In the framework of the solar energy activities carried out by INTA’s Energy Laboratory, in 1990 a programme on solar hydrogen production and utilization was started. Within the general agreement between INTA and the regional government of Andalucia, a test and research plant for solar hydrogen production via water electrolysis was designed and erected in Huelva. The construction of the plant started in November 1991 and was finished in February 1992. The main objective of this facility is to test and evaluate the different technologies associated with solar hydrogen production, as well to stimulate research and development in this field in Spain. The plant is composed mainly of a 8.5 kW photovoltaic field with a flexible configuration of output voltage and current, and a 5.2 kW alkaline electrolyser. A test bench for PV module characterization, a conventional a.c./d.c. converter for electrolyser characterization and a d.c./d.c. maximum power point tracker as power matching system complete the test facility. The paper contains a technical description of the installation, the test plan to be performed, results concerning electrolyser characterization and some preliminary results of continuous operation. NOMENCLATURE INTA Instituto National de Ttcnica Aeroespacial MPPT Maximum power point tracker 1. INTRODUCTION As is widely agreed, water electrolysis is one of the best known and well-developed ways for hydrogen produc- tion from nonfossil sources. Solar photovoltaic conversion for electricity produc- tion is well established in Spain at an industrial and commercial level. The combination of both technologies (photovoltaic + electrolysis) to produce hydrogen be- comes a very interesting project for energy-dependent countries with high solar irradiation levels. Hydrogen production feasibility by solar-photovol- taic-powered electrolysis has already been stated, and new advanced technologies are emerging to improve its efficiency and reduce costs. In this framework, the Energy Laboratory of INTA has started a programme whose main objectives are to verify the feasibility of solar hydrogen production, to evaluate the different technologies of the components in a solar hydrogen production plant and to stimulate the Spanish research and development in this field looking towards component development. Within this programme, the first experience, partially financed by the regional government of Andalucia, was focussed to make ready a test and research facility on the base of a 8.5 kW PV field and a 5.2 kW alkaline electro- lyser. The plant was constructed in Huelva (in the southwest of Spain), where INTA’s Energy Laboratory has its main solar test centre (Fig. 1). Erection and commissioning of the plant was finished in February 1992 and the start-up was done in March 1992. During the second quarter of 1992, the plant’s components were characterized Cl], and since November 1992 the system works in daily operation coupled to the PV field. 2. TECHNICAL DESCRIPTION The facility was arranged into different systems as indicated in Table 1: power generation, electrolysis, control, data acquisition and auxiliary systems. Figure 2 shows a block diagram of the plant including the above-mentioned systems, and Table 2 summarizes the main components’ characteristics. 2.1. Photovoltaic field The PV field is composed of 144 modules (36 cells each), 30% of which have 8 connectors to place output voltages and currents at intervals of 9 cells (4.5V and 995