The load frequency control (LFC) of a multi-area interconnected power system (IPS) is presented in this chapter. The multi-area IPS in this work has two areas that incorporate power generation units like thermal and hydro with non-linear practical constraints. Moreover, area 1 of the multi-area IPS is integrated with renewable-based systems such as wind turbine generation, fuel cells, and aqua electrolyzers, and further diesel power generation is also penetrated. For better control over the stability of the IPS network, this work suggests the osprey optimization algorithm (OOA) tuned three-degree-of-freedom proportional-integral-derivative (3DOFPID) controller as a secondary controller, and the investigation is performed for a 10% step load perturbation (SLP) in area 1. Moreover, the communication time delays (CTDs) are deliberated with the investigation model, and their subsequent effect on the IPS performance is showcased. Later, the coordinated control approach of capacitive energy storage (CES) and a thyristor-controlled series compensator (TCSC) is employed for the investigative model in this work under the OOA-tuned 3DOFPID controller. The improvement in the dynamic behavior of the multi-area IPS is achieved with the deployment of the additional CES-TCSC control strategy. Finally, the multi-area IPS is targeted with a wide range of loads and parametric uncertainties to validate the robustness of the implemented control techniques.