Desalination 153 (2002) 9–16 0011-9164/02/$– See front matter © 2002 Elsevier Science B.V. All rights reserved Presented at the EuroMed 2002 conference on Desalination Strategies in South Mediterranean Countries: Cooperation between Mediterranean Countries of Europe and the Southern Rim of the Mediterranean. Sponsored by the European Desalination Society and Alexandria University Desalination Studies and Technology Center, Sharm El Sheikh, Egypt, May 4–6, 2002. *Corresponding author. A wind-powered seawater reverse-osmosis system without batteries Marcos S. Miranda*, David Infield Center for Renewable Energy Systems Technology CREST, Loughborough University, LE11 3TU, UK Tel. +44 (1509) 228144; Fax +44 (1509) 610031; email: M.S.Miranda@lboro.ac.uk Received 20 April 2002; accepted 30 April 2002 Abstract The development of small-scale stand-alone desalination systems is important to communities on islands and in isolated inland areas. In such places, electricity supplies are often expensive and unreliable, while the wind resource is abundant. The system presented here comprises a 2.2 kW wind turbine generator powering a variable-flow Reverse osmosis (RO) desalination unit. It is highly efficient, rugged, built with off-the-shelf components and suitable for use in remote areas. Operation at variable-flow allows the uncertainty and variability of the wind to be accommodated without need of energy storage. Batteries, which are common in stand-alone systems, are avoided and water production is dependent on the instantaneous wind speed. A model-based control strategy is used to independently maximize both the energy extracted from the wind and the water output of the RO unit. A computer model of the system has been developed based on component models, identified through laboratory testing. Performance predictions are presented and discussed. Keywords: Wind power; Reverse osmosis; Energy recovery; Seawater desalination; Renewable energy 1. Introduction There is no need to dwell on the importance of energy in the daily life of modern society and that its availability relies mostly on the existence of fossil fuels. Increasing awareness of the depletion of current sources has led to a global effort in the research and development of renewable energy technologies, such as wind, solar, tidal and geo- thermal energy.