On June 15, the Department of Justice lodged a proposed Amended Consent Decree with the U.S. District Court for the Eastern District of Michigan in a lawsuit against the City of Wyandotte, Michigan, over coal-fired emissions from the city’s power plant.
In 2011, the Justice Dept, entered into a Consent Decree with Wyandotte to resolve allegations under the Clean Air Act that Wyandotte’s coal-fired Units 7 and 8 violated the emissions limits set forth in Wyandotte’s Title V permit, its Prevention of Significant Deterioration permit, the New Source Performance Standards, and the federally enforceable Michigan State Implementation Plan.
After entry of the Consent Decree, Wyandotte violated several provisions of the original Consent Decree, including failing to submit required reports. Additionally, Wyandotte made some operational changes. Under the proposed Amended Consent Decree, Wyandotte will pay $425,000 in stipulated penalties, restrict Unit 7 to burning only natural gas, and retire Unit 8.
Justice will publish a notice of this decree in the June 24 Federal Register, within comments on it taken for 30 days after that publication date.
The 2011 complaint sought injunctive relief and the assessment of civil penalties for alleged violations of the emissions limits and reporting requirements for opacity, NOx, SO2 and carbon monoxide at the city power plant. In September 2011, the District Court entered the Consent Decree. The Consent Decree required Wyandotte to install new emission controls, implement operational practices to reduce emissions, pay a civil penalty of $112,000, and perform a supplemental environmental project at an estimated cost of $210,000.
Wyandotte voluntarily began burning natural gas instead of coal at Unit 7 in March 2012 and thereafter requested a modification of the Consent Decree to reflect the operational change. Also, Wyandotte triggered the Consent Decree’s requirements to install Selective Non-Catalytic Reduction to achieve at least an additional 50% reduction in NOx emissions at Unit 8 as well as perform a study of the limestone feed system and implement the findings to achieve at least 25% additional reduction in SO2 emissions.
As of the date of lodging for the amended decree (June 15), Wyandotte needs to operate Unit 7 by firing only natural gas. Wyandotte has to remove it as a coal unit in Michigan’s air inventory. Wyandotte needs to continuously operate its existing Low NOx Burners system consistent with the manufacturer’s specifications, the operational design and maintenance limitations of Unit 7, and good engineering and air pollution control practices for minimizing emissions. Wyandotte has to continuously operate its existing Separated Over-Fire Air consistent with the manufacturer’s specifications, the operational design and maintenance limitations of Unit 7, and good engineering and air pollution control practices for minimizing emissions. As of the date of lodging, Wyandotte has to achieve and continuously maintain compliance with an emissions limit no greater than 0.20 lb/MMBtu for NOx as a 3-hour rolling average.
Also, Wyandotte has to install and continuously operate an SNCR on Unit 7 consistent with the manufacturer’s specifications, the operational design and maintenance limitations of Unit 7, and good engineering and air pollution control practices for minimizing emissions, if: prior to termination of this Amended Consent Decree, the duration of the city’s Unit 7 NOx exceedances is 1% or more of total operating time during any calendar year; or prior to termination of this Amended Consent Decree, the duration of the Unit 7 NOx exceedances is 2% or more of total operating time during any calendar quarter. The SNCR must be designed to achieve continuous compliance with the Title V Renewable Operating Permit and to achieve, on a continuous basis, at least an additional 50% removal of NOx from its Title V Renewable Operating Permit emission limit for NOx for Unit 7. For example, if the current permitted limit for NOx in the Title V Renewable Operating Permit is 0.20 lb./MMBtu as a 3-hour average, then the SNCR must be designed to achieve, on a continuous basis, 0.10 lb./MMBtu as a 3-hour average.
By June 30, 2016, under this new agreement, Wyandotte has to permanently retire Unit 8.
The Michigan Department of Environmental Quality’s Air Quality Division last year was handling a Permit to Install (PTI) application from Wyandotte Municipal Services covering the proposed installation and operation of two new boilers and a combustion turbine with heat recovery steam generator (HRSG).
The existing facility is located in Wyandotte, Wayne County. Wyandotte currently operates three boilers (Units 5, 7, and 8), and three engine generators for back-up power. Unit 5 is a natural gas-fired boiler and is used for back-up to the other two boilers. Unit 7 is a wall-fired pulverized coal-fired boiler that is also capable of firing natural gas and propane. Unit 8 is a circulating fluidized-bed boiler capable of firing coal, untreated virgin wood chip waste and tire-derived fuel.
Wyandotte was permitting new natural gas-fired equipment: two boilers known as Unit 9 and Unit 10; and a combustion turbine with heat recovery steam generator (HRSG). Wyandotte would also permanently shut down the Unit 8 boiler under this permitting. The proposed new natural gas-fired boilers are rated at 160 million British thermal units per hour (MMBtu/hr) and 90 MMBtu/hr. The combustion turbine is natural gas-fired and is rated at 20 MW output or 247 MMBtu/hr heat input. The natural gas-fired duct burner for the HRSG is rated at 90 MMBtu/hr, and is not capable of operating separately from the combustion turbine.
The Unit 8 boiler is a 25-MW, 900 psi circulating fluidized-bed boiler with a maximum steam generating capacity of 275,000 pounds per hour. Natural gas is used in the boiler for start-up. The boiler utilizes limestone injection to control SO2 emissions and a baghouse for particulate matter control.