<p>Electric vehicles (EVs) assist in balancing load demand and power generation by serving as flexible energy storage units. The unpredictable behaviour of EV owners and the limited capacity of individual EVs have led to the concept of EV aggregators, which aim to boost EV involvement in the ancillary services market. The use of EV aggregators in frequency control operations can lead to time-varying delays in load frequency control (LFC) systems. Since the performance of the controller relies on its configurations, these configurations must be optimally designed to achieve improved outcomes in an LFC system with dynamic delays. Therefore, physics-inspired optimization called Fick’s law optimization (FLO) is proposed to tune the robust proportional-integral (PI) controller parameters. Additionally, the proposed LFC performance is assessed using integral error indices. This work simulates and analyses single and two-area LFC systems with EV aggregators and dynamic delays. Results demonstrate that the suggested scheme minimizes frequency fluctuations compared to other controllers. Furthermore, the FLO-based PI controller notably reduces overshoot and settling time of frequency changes.</p>