Frequency regulation in high-renewable grids using small modular reactors (SMR): a comparison of pid and mpc strategies

The rapid penetration of renewable energy sources (RESs) into modern power systems has introduced unprecedented challenges in frequency regulation, primarily due to the intermittency and variability of wind and solar generation. Traditional large-scale nuclear and fossil-fuel-based power plants, while reliable, lack the flexibility required for rapid response to frequency fluctuations in high-renewable environments. Small modular reactors (SMRs) have emerged as a promising alternative, combining nuclear reliability with enhanced operational flexibility (Elfaramawy et al. 2025). This research presents a comparative study of two control strategies—proportional-integral-derivative (PID) and model predictive control (MPC)—for frequency regulation in a renewable-rich grid, where SMRs act as flexible balancing resources. Using validated Simulink-based dynamic models of SMR dynamics, grid frequency response, and renewable variability, the performance of PID and MPC controllers in mitigating disturbances caused by renewable fluctuations and large-scale contingencies was analyzed. Results indicate that both controllers provide effective frequency regulation, with MPC offering modest advantages in overshoot suppression and settling time. While PID demonstrates reliable performance and ease of deployment, MPC enables predictive optimization and explicit constraint handling. The findings suggest that both control strategies are viable for SMR-based frequency support, with MPC providing incremental improvements in dynamic response for future high-renewable grids.