Duke permits new emissions controls for two Cayuga coal units

The Indiana Department of Environmental Management (IDEM) has gone out for public comment until Aug. 29 on a draft air permit approval that would allow Duke Energy Indiana to install new selective catalytic reduction (SCR) systems for NOx control on the coal-fired Cayuga plant.

“If approved by IDEM’s Office of Air Quality (OAQ), this proposed modification would allow Duke Energy Indiana – Cayuga Generating Station to make certain changes at their existing source,” said an agency notice. “Duke Energy Indiana – Cayuga Generating Station has applied to install Selective Catalytic Reduction (SCR) on each Unit to control emissions of NOx and to convert Hg into a form which can be more easily captured with the existing controls.” The proposed SCR system will include an Arsenic mitigation system, SO3 mitigation system, and Ammonia storage facility. Duke Energy is proposing to install an activated carbon injection system on each Unit to achieve additional Hg control. In addition, Duke is proposing to install a dry fly ash handling and ash fixation system, according to the notice.

Boiler No. 1 at the plant is a dry bottom, pulverized coal-fired boiler installed in 1967, with a nominal heat input capacity of 4,802 million Btu per hour (MMBtu/hr), with an electrostatic precipitator (ESP) for control of particulates, a flue gas desulfurization (FGD) for control of SO2, and exhausting to stack 1. Stack 1 has continuous emissions monitors (CEMs) for NOX and SO2 and a continuous opacity monitor. Boiler No. 1 was configured with a low NOX burner in 1993. SCR to control NOx, dry sorbent injection (DSI) to control SO3, and activated carbon injection (ACI) to assist in control of Hg emissions are scheduled to be installed by 2015.

Boiler No. 2 is a dry bottom, pulverized coal-fired boiler installed in 1968, with a nominal heat input capacity of 4,802 MMBtu/hr, with an ESP for control of particulate matter, and FGD for control of SO2, and exhausting to stack 2. Stack 2 has CEMs for NOX and SO2 and a continuous opacity monitor. Boiler No. 2 was configured with a low NOX burner in 1993. SCR, DSI and ACI are scheduled to be installed by 2015.

Duke Energy Indiana is a unit of Duke Energy (NYSE: DUK).

The primary features of Duke Energy Indiana’s Phase 2 compliance plan for the 2014-2015 period include new, “critical path” SCRs on Cayuga Units 1-2. The utility described its plans in recent filings with the Indiana Utility Regulatory Commission. Other Phase 2 projects include:

  • DSI systems on Cayuga Units 1-2 for SO3 mitigation;
  • ACI systems on Cayuga Units 1-2, all five Gibson units and Gallagher Units 2 and 4; and
  • mercury re-emission chemical injection systems on Cayuga Units 1-2 and Gibson Units 1, 2, 3 and 5.

These Phase 2 projects were designed primarily to meet the requirements of the U.S. Environmental Protection Agency’s Mercury and Air Toxics Standards (MATS) and are targeted towards mercury reductions at these units (with the exception of the DSI systems at Cayuga, which are proposed for SO3 mitigation). The company tentatively plans to file its Phase 3 compliance plan with the commission by the spring of 2013, said Douglas Esamann, President of Duke Energy Indiana.

The implementation of the prior, Phase 1 plan was substantially complete by the fall of 2008, when the second of the new scrubbers at the Cayuga plant was placed into service.

Esamann was one of several Duke officials that supplied June 28 testimony to the commission in an environmental cost review case. He noted that EPA programs like MATS and the Cross-State Air Pollution Rule (CSAPR) put a heavy burden on the company’s coal units. “Duke Energy Indiana’s only options for each unit are clear – lower emissions or shut it down,” he added. “While our compliance options under the MATS rule are severely limited, long-term environmental compliance planning and implementation remains extremely complex for electricity generators.”

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.