This paper addresses practical challenges encountered in Economic Load Dispatch (ELD) systems, which often involve non-convex objective functions and a combination of equality and inequality constraints, making the search for the global optimum a challenging task. Additionally, various nonlinear constraints, such as valve-point loading, ramp rate limits, prohibited operating zones, and nonlinear cost functions, must be considered for practical operation. To tackle these issues, the paper presents an enhancement to the Firefly Algorithm (FA), a swarm intelligence algorithm inspired by the flashing pattern and behavior of fireflies. FA is a population-based algorithm widely used for optimizing various problems. In this study, the authors propose a modification to FA by introducing an inertia weight. The adapted FA is specifically applied to address ELD problems. To assess the performance of the proposed variant, experiments were conducted using a 10-unit system. The results clearly demonstrate that the modified FA with the inclusion of an inertia weight outperforms other methods in achieving more economically optimized loads.