This work deals with the design and construction of an automation system for controlling the electric energy flows that take place at the continuous current bus (DC Bus) of a wind-solar system with hydrogen support. The automation system is based on a Siemens PLC s7_313C_2DP. This PLC was equipped with a Micro Memory Card (MMC) of 2 MB in order to allow the massive storage of data related to the control and monitoring of the test-bed. This system has to perform the required switching between the components of the hybrid electric energy generator. These elements are: photovoltaic generator, wind-turbine generator, fuel-cell system, and electrolyzer. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.