ELYGRID Project aims at contributing to the reduction of the total cost of hydrogen produced via electrolysis couple to Renewable Energy Sources, mainly wind turbines, and focusing on mega watt size electrolyzes (from 0,5 MW and up). The objectives are to improve the efficiency related to complete system by 20 % (10 % related to the stack, and 10 % electrical conversion) and to reduce costs by 25%. The work will be structured in 3 different parts, namely: cells improvements, power electronics, and balance of plant (BOP). Two scalable prototype electrolyzers will be tested in facilities which allows feeding with renewable energies (photovoltaic and wind)