Economics of nitrogen oxides, sulfur oxides, and ash control systems for coal-fired utility power plants

A US Environmental Protection Agency (EPA)-sponsored economic evaluation was made of three process combinations to reduce NO/sub x/, SO/sub 2/, and ash emissions from coal-fired utility power plants. One case is based on a 3.5% eastern bituminous coal; the other two are based on 0.7% western subbituminous coal. NO/sub x/ control is based on an 80% reduction from current new source performance standards (NSPS); SO/sub 2/ and fly ash control are based on meeting the current NSPS. Selective catalytic reduction (SCR) is used for NO/sub x/ control in all three cases. Limestone scrubbing and a cold-side electrostatic precipitator (ESP) are used in the 3.5% sulfur coal case. Lime spray dryer flue gas desulfurization (FGD) and a baghouse for particulate collection are used in one 0.7% sulfur coal case; limestone scrubbing and a hot-side ESP are used in the other. The economics consist of detailed breakdowns of the capital investments and annual revenue requirements. For systems based on a 500-MW power plant, capital investments range from $167 to $187 million (333 to 373 $/kW) and first-year annual revenue requirements from $54 to $60 million (29 to 33 mills/kWh). The 3.5% sulfur coal case is highest because of the higher SO/sub 2/more » control costs. The case with the spray dryer and baghouse is marginally lower in cost than the case with limestone scrubbing and hot-side ESP. Costs for NO/sub x/ control range from one-fourth to one-half of the total costs, largely because of the high cost of the catalyst. The costs of the overall systems and the relationships of the component costs are complexly interrelated because of the interactions of the three processes.« less