Weather-induced changes in the tradeoff between SO₂ and NO(x) at large power plants

Mae Moh Power Plant generates 30% of Thailand's electricity by burning high sulfur content coal which comes from adjacent mines. The resulting sulfur dioxide emissions have been blamed for acid rains in the Mae Moh valley in 1991 and 1992. Mae Moh is now adding desulfurization plants to 60% of its 1994 generating capacity - the four largest units of an 11-unit facility. In 1995-1996, Mae Moh added two additional large units with desulfurization plants attached. The desulfurization plants should eliminate 95% of the sulfur dioxide produced by the generating units to which they are attached. In the past, abatement efforts have focused on sulfur dioxide. However, with the addition of the desulfurization plants and the expansion of Mae Moh's capacity, nitrogen oxides produced by Mae Moh's generation of electricity will become an increasingly important problem. This paper examines the tradeoff, and how climate affects it, between concentrations of sulfur dioxide and nitrogen oxides just prior to the addition of the desulfurization plants. Mae Moh can use knowledge of this tradeoff in its efforts to minimize the environmental damage from generating electricity.