Introduction to renewable energy systems and the associated problems.- Selected renewable energy systems and formulation of their problems.- Advanced engineering optimization techniques and their role in energy systems optimization.- Working of Jaya and Rao optimization algorithms and their variants.- Multi-attribute decision-making methods and their implementation in energy systems.- Optimization of wind farm layouts.- Optimization of the selected solar assisted energy systems.- Optimization of the selected bio-energy systems.- Optimization of hydro energy, geothermal, and ocean thermal energy systems.- Concluding remarks.