<p>Modern power systems face stability issues, especially from frequency fluctuations caused by imbalances in generation and demand. These deviations can damage equipment, reduce power quality, and lead to blackouts. The rise of renewable energy adds complexity to frequency management. To stabilize frequency, ensure reliable power, and prevent cascading failures, Load Frequency Control (LFC) is essential. This article demonstrates the study of a three-area LFC system integrated with various renewable energy sources (RES) such as precise wind turbine systems (PWTS) and a realistic dish Stirling solar thermal system (RDSTS). A novel cascade controller, tilt-integral and fractional-order-integral-derivative-filter (TI-FOIDN), is proposed as a supplementary controller. The proposed control strategies utilize a recent optimization technique known as the hybrid Emperor Penguin Optimization (HEPO) Algorithm to fine-tune the controller and RES parameters. This is achieved by employing a novel performance index called the Hybrid Peak Area-Integral Squared Error (HPA-ISE). Results show that the TI-FOIDN controller delivers superior dynamic performance compared to FOPI and TIDN controllers. Optimized with HPA-ISE, the system dynamics outperform those using the conventional ISE performance index. The system performance was also validated with the Real Time (RT)-Lab simulator, which revealed improved system performance compared to MATLAB. Moreover, RES integration enhances the system’s dynamics over thermal-only configurations. Further, the inclusion of AHVDC alongside the AC tie-line and various flexible alternating current transmission systems (FACTS) devices such as Thyristor controlled series capacitors (TCSC) and Interline Power Flow Controllers (IPFC) enhances system responses, and the ideal locations for placing FACTS devices are determined in areas with disturbances and lower capacity.</p>