The Dynamic Economic Emission Dispatch Problem (DEED) is a well-known problem in the study of thermal power generation. The goal of the DEED is to meet the demand change by arranging the capacities of power generators to reduce fuel cost and emission. In recent years, the high environmental awareness, the decreasing petrochemical energy, and the increasing energy demand such that the DEED is more important and popular than before. Most of algorithms for the DEED are either limited by less than ten power generators or without considering the power generation limit. The former is impractical due to that the number of power generators in current thermal power plants can be up to 14; the latter results in infeasible solutions. To overcome the above two obstacles, a new algorithm called the SSO-DE-SQP hybrid with the Simplified Swarm Optimization (SSO), Differential Evolution (DE), and Sequential Quadratic Programming (SQP) is developed to solve the larger-size DEED with the power generation limit. The performance of the SSO-DE-SQP is demonstrated by comparing with two existing well-known methods: DE-SQP and PSO-SQP with up to 15 generators for the DEED.