The gradual exhaustion of natural resources, particularly energy sources, and the various problems involved in their life-cycle, makes it necessary to promote a renewably derived hydrogen economy, in which hydrogen is produced from clean sources. In this paper, the control system for an installation for producing hydrogen via electrolysis using only a 250kWp photovoltaic generator is presented. Computer simulation was used to design and confirm its correct performance. The results obtained ensure the installation's high energy yield. (c) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.