In this paper, an improved particle swarm optimization algorithm (PSOCS) that integrates with a clone selection (CS) principle of artificial immune system is proposed to solve dynamic economic emission dispatch (DEED) problem. Classical particle swarm optimization method is easy to fall into stagnation when no particle discovers a position that is better than its previous best position. To overcome the disadvantage, the CS mechanism is used to evolve the personal best swarm (i.e., $$P^{\mathrm{best}}$$ ) at every generation. The fittest particles in $$P^{\mathrm{best}}$$ will be cloned independently and proportionally to their fitness. In order to force PSOCS jump out of stagnation, a hybrid mutation scheme (called R/1orCB/1) is developed to mutate the clones generated. A constrain-handling approach is utilized to repair infeasible solutions for enhancing the ability of adapting to the DEED problem with various strong constraints. In numerical experiments, the proposed PSOCS is applied to solve three test cases (5-unit, 10-unit, and 15-unit systems) with nonsmooth fuel cost and emission functions. Simulation results indicate that the PSOCS can find the high-quality solutions for the DEED problem, when compared with the most recent methods reported in the literature.