This paper aims at proposing a distributed control approach for optimal power dispatch towards environment-friendly power grids. In order to do so, both electric generation and pollutant emission costs are properly incorporated into a unique objective function of an optimization problem subjected to physical constraints of the considered power system. Consequently, we propose an approach based on the Alternating Direction Method of Multipliers (ADMM) to obtain the globally optimal solution of that optimization problem in a distributed manner under a fast convergence. As a result, each generation unit in a power system can derive by itself an optimal generated power that minimizes with compromising both fuel and emission costs while satisfying both global and local physical constraints caused by the whole system and by its own. The most distinguished feature of this approach is that the power balance constraint is always guaranteed during the execution of the algorithm. Finally, the performance of our proposed approach is illustrated through the simulation to a realistic power system and the comparison with another method.