Seasonalepisodic control of acid deposition

Abstract

This report contains the climatological, technical and economic factors for episodic and seasonal control of emissions in existing power plants. Analyzing a large data set of acid deposition for the years 1982-85, we find that the bulk of acid deposition comes down in a few precipitation episodes per year, mostly concentrated in the summer months. However, the episodes do not occur over wide areas, and are difficult to predict. About 75% of the annual acid deposition occurs during the summer half-year, April through September. Therefore, it would be effective to reduce acid precursor emissions, SO[subscript x] and NO[subscript x], during that period. One method to accomplish the summer precursor emission reduction is substituting natural gas (NG) for oil and coal in large electric utility and industrial boilers.

Gas contains no sulfur and emits less NO[subscript x] than oil or coal. The cost of a summer fuel substitution is primarily dependent on the delivered fuel price differential and only to a small extent on the retrofit cost for dual fuel use. For example, with a delivered fuel price differential of $1.5/MMBtu, the annualized incremenmtal cost of electricity would be about 8 mills/kWh. For the same fuel price differential, the sulfur removal costs range from $400 - $1750 ton SO[subscript 2] depending on sulfur content of the fuel. If credit were given for the greater effect of summer emission reductions, the "effective" removal costs would be considerably less.