CSIR-National Aerospace Laboratories (NAL) developed and validated indigenous design methodologies for optimizing wind turbine rotors and blades for India's low/moderate wind regimes, as part of a project sponsored by the Centre for Wind Energy Technology (C-WET). The comprehensive methodology integrated Eppler's airfoil design code, in-house IMPRANS CFD solvers, GH-BLADED aero-elastic analysis, and ANSYS/NASTRAN structural analysis to design 300 kW and 500 kW wind turbine blades. Prototype 300 kW blades were fabricated using glass/epoxy composites and field-tested at Kethanur Wind Farm, Coimbatore, showing superior performance with 6.5% higher power output than existing blades. The validated methodology was subsequently applied to a 500 kW research wind turbine, successfully tested during 2009-2010. Gurney flaps were investigated as performance augmentation devices, demonstrating significant power improvement through tow-testing experiments. Key design parameters include 24.2m rotor diameter, 65 rpm, Class II wind turbine classification, and cut-in/cut-out speeds of 4.5/34 m/s. This project has established a reliable indigenous design data bank, enabling cost-effective wind turbine development tailored for Indian conditions.