The Kentucky Division for Air Quality on Feb. 10 released a draft permit that covers the shutdown of two coal units at the Tennessee Valley Authority‘s Paradise power plant in the western part of the state, and a gas-fired addition at the site.
In March 2014, the Division received an application from TVA for a significant revision to the current title V operating permit for the Paradise plant. TVA proposes to construct and operate a “three-on-one” combined-cycle facility, which consists of three natural gas-fired combustion turbine (CT) generators; three heat recovery steam generators (HRSGs) with natural gas-fired duct burners, catalytic oxidation, and selective catalytic reduction (SCR); one reheat, condensing steam turbine generator; one natural gas-fired auxiliary boiler; three natural gas heaters; one diesel fire pump; one multiple cell cooling tower; two distillate-oil storage tanks and two aqueous ammonia tanks. Nominal generation capacity is 1,085 MW at 59 degrees F.
Three auxiliary boilers will also be installed to assist with startup and shutdown of the Unit 3 coal boiler. Units 1 and 2 are to be shut for clean-air reasons, with Unit 3 to survive as a coal-fired facility.
“The combined-cycle facility will replace the two existing PAF coal-fired boilers, Units 1 and 2, to bring the source into compliance with the Mercury and Air Toxics Standards (MATS),” said a Division permit document. “Actual baseline emissions from the retirement of Units 1 and 2 are being used to net against the potential emissions from the proposed project. As a result, there will be no net emissions increase resulting from the proposed project and Prevention of Significant Deterioration of Air Quality (PSD) permitting requirements will not apply.”
Paradise is located next to the Green River in Drakesboro, Kentucky. The facility currently consists of three cyclone furnace coal-fired boilers (Emission Units 1, 2 and 3), three distillate oil-fired heating boilers, eleven distillate oil-fired space heaters, three natural-draft cooling towers, and solid fuel, limestone, ash, and gypsum handling processes. The boilers are fueled by coal with distillate fuel oil (fuel oil) being used for the start up and low load conditions to ensure flame stability. These units are also fueled using approximately 100,000 gallons of used oil and non-hazardous solvents along with non-hazardous contaminated soil, absorbent material, filters, rags containing oil or other non-hazardous material, and papers that are considered confidential. Paradise is currently co-firing coal fines that are blended with other coal that is about 14% by weight, even though a range of 6%-8% by weight is the expected rate.
Emission units 1 and 2, which are to be retired, are identical cyclonic steam generating boilers, each having a maximum capacity of 6,959 MMBtu/hr, with nameplate electric generating capacity of 704 MW. The units are equipped with overfire air to reduce nitrogen oxides (NOx), and the boiler exit flue gas is routed through the Selective Catalytic Reduction (SCR) modules for nitrogen oxides emission control.
Emission unit 3 is a cyclonic steam generating boiler with a maximum capacity of 11,457 MMBtu/hr. The nameplate capacity is 1,150 MW. The unit is also equipped with staged overfire air to reduce NOx. Just like units 1 and 2, the flue gas furnace section can be directed to the SCR for NOx emission control.
The Division noted that in April 2014 it received a letter from TVA requesting a one-year compliance extension of all requirements of MATS for Units 1 and 2. The Division issued a letter of approval in May 2014. That extended deadline is April 2016.
Saying that TVA properly followed its environmental review procedures in deciding to shut the two coal units at Paradise and build the gas-fired replacement, a federal judge on Feb. 3 dismissed a July 2014 lawsuit filed by the coal industry against that TVA decision. The Feb. 3 order was by Judge Joseph McKinley Jr. out of the U.S. District Court for the Western District of Kentucky. The plaintiffs in the case included the Kentucky Coal Association and several other parties. They had filed a complaint seeking a declaration that TVA violated the National Environmental Policy Act (NEPA), the Administrative Procedures Act and the TVA Act by conducting a faulty environmental assessment process.