Changes in the quality of coal delivered to Kentucky power plants, 1978 to1997: responses to Clean Air Act directives

Burning of coal supplies more than 95% of the electricity generated in Kent ucky. Coal-burning utilities have responded to evolving clean air standards in a number of ways, including adding flue-gas desulfurization (FGD) to ex isting plants or switching to lower sulfur coals. No power plant in Kentuck y burned < 1% sulfur coal in 1978. By 1997, many utilities had switched to lower sulfur and, in some cases, lower ash coal. The means of switching var ied, with many choosing Central Appalachian coals. One plant now uses low-s ulfur western US bituminous coal after having used Central Appalachian coal s while another plant uses subbituminous Powder River Basin coal in a blend with Illinois Basin coal. The rank range of coals purchased has widened, n ot only with the addition of subbituminous coals but also with the use of m edium and low volatile bituminous coals. No other state matches Kentucky in FGD capability, with 48% of the state's generating capacity equipped with FGD as an SO2 reduction option. The expansion of FGD has maintained a marke t for higher sulfur coal. The newest power plants were designed in tandem w ith the FGD system and can handle coals with > 4% sulfur. Quality of delive red coals has changed significantly over the past 20 years, and will contin ue to change as coal-fired power plants continue to work to meet the challe nges presented by existing and potential new clean air standards. (C) 1999 Elsevier Science B.V. All rights reserved.