A combined finite element method/ method of characteristics algorithm (FEMC) is presented for estimating the corona power loss associated with wire duct electrostatic precipitators (WDEP). The finite element method and the method of characteristic are used iteratively to get a self consistent solution of the describing equations, namely Poisson's equation. The authors feel that, as these precipitators are used for air pollution control, this is a step towards a complete determination of its efficiency. The effectiveness of the new approach is tested by comparing the computed results with experimental values. The agreement is found to be satisfactory.