An electrodialysis desalination plant has been set up and tested while driven from an off-grid wind-energy system. Prior to analysing the behaviour of the system off-grid, a thorough knowledge of the operational modes and constraints is required. That information is obtained through a number of tests done on-grid. This paper presents some results obtained while operating on-grid in a work carried out within the framework of a wider scope project, located in Gran Canaria Island (Spain). The main goal of this project is to test and identify the most suitable desalination systems for connection to the above-mentioned medium-scale off-grid wind farm. After preliminary modelling using proprietary software, a number of on-grid tests at different flow rates and fixed feed conductivity were carried out. The results include curves for the relationship between voltage applied and product conductivity (between 100 and 280 muS/cm), as well as unit energy consumption (from 1.48 to 2.32 kWh/m(3)). The data gathered showed that EDR can easily adapt to a variable power supply such as wind energy, and they were used later in off-grid tests.