**Abstract:**
Economic load dispatch (ELD) is a sub problem of the optimal power flow (OPF) having the objective of fuel cost minimization. The fuel cost equation of a thermal plant is generally expressed as continuous quadratic equation. In real situations the fuel cost equations are non-convex and sometimes non-continuous. In order to solve such economic load dispatch problems, various methods are discussed in this paper. The results of these methods are compared and it is seen that artificial bee colony approach is very useful and efficient approach to solve economic dispatch problem among all the approaches.

**Keywords:**
Economic load dispatch, Particle swarm optimization, Tabu Search Method, Social Spider Optimization, Gravitational Search Method, Teaching Learning Based Optimization, Krill Herd Method, Artificial Bee Colony.