This article presents two novel methods based on the Marine Predators Algorithm (MPA) and the Tunicate Swarm Algorithm (TSA) for solving the economic dispatch problem in the electric power system. The objective of the study is to satisfy the power system’s load demand and the operational constraints while incurring the minimum possible fuel cost. The objective function of the optimization is represented as the quadratic cost functions of the generators in the system. A penalty function is also incorporated into the objective function to ensure the solutions produced by MPA and TSA do not violate the system’s operational constraints. The MPA and TSA models have been implemented on two test systems with six, and fifteen generator units. To determine the effectiveness of the proposed method to solve the ED problem, the results obtained using the MPA and TSA have been compared with other methods in the literature. The results show that the MPA and TSA perform very competitively with other methods.