This master’s thesis focuses on the structural design, optimization, and techno-economic assessment of a 15 MW offshore wind turbine blade. In the current energy context, the optimisation of renewable energy technologies is playing an important role, especially for technologies such as offshore wind power, which are constantly evolving. The work aims to do a structural analysis and aero-structural optimization of a wind turbine blade in different wind conditions and do a simplified techno-economic modelling to evaluate its performance in different wind and geographical scenarios. After a briefly introduction to wind energy, the study begins with the definition of a reference 15 MW offshore wind turbine blade layout using Co-Blade.