Dynegy pursues reduction in air limits for Danskammer Unit 4

The New York Department of Environmental Conservation is taking public comment until Nov. 30 on an air permit change that would sharply lower the allowed NOx, SO2 and particulate matter (PM) emissions rates at Unit 4 of the Danskammer power plant.

Dynegy Northeast Generation is seeking a change under the Best Available Retrofit Technology (BART) rules for Unit 4.

  • For NOx, the change would lower the existing emission limit from 0.42 lb/mmBtu to 0.12 lb/mmBtu (24-hr average during ozone season, 30-day average during non-ozone season) to meet NOx RACT/BART, effective July 1, 2014.
  • For SO2, it would lower the existing emission limit from 1.1 lb/mmBtu to 0.5 lb/mmBtu (24-hr average), effective July 1, 2014.
  • For PM, it would lower existing limit from 0.1 lb/mmBtu to 0.06 lb/mmBtu (1-hour average), also effective July 1, 2014.

Danskammer consists of four Combustion Engineering (CE) tangentially-fired steam generating boilers (Units 1-2) rated at 65 MW each (capable of firing No. 6 fuel oil and natural gas); a CE 135-MW Unit 3 capable of firing No. 6 oil, natural gas and coal; and a CE unit rated at 235 MW, Unit 4, also capable of combusting oil, natural gas and coal. Units 1-2 began commercial operation in 1951 and 1954 respectively; Unit 3 began operation in 1959; and Unit 4 began operation in 1967. Unit 4 began commercial operation on coal, but was converted to residual oil firing in 1970, with a reconversion to coal in 1987. The unit retains the capability to burn all three fuels, the DEC noted.

This capacity at Danskammer has been subject to a bankruptcy for Dynegy Northeast Generation. In the bankruptcy case, Dynegy gave up its leases on the capacity at Danskammer and the gas-fired Roseton plant and that capacity is now up for sale. This capacity is at this point owned by affiliates of Public Service Enterprise Group (NYSE: PEG), which had been leasing it to Dynegy.

The U.S. Environmental Protection Agency recently took final action on the Regional Haze State Implementation Plan (SIP) submitted by the state of New York, approving SIP revisions containing permits for BART. Although New York addressed most of the issues identified in an EPA proposal, EPA promulgated a Federal Implementation Plan (FIP) to address two sources where EPA is disapproving New York’s BART determinations. This rule was effective on Sept. 27.

EPA’s FIP contains BART determinations and emission limits for Roseton and Danskammer. EPA disapproved New York’s SO2 BART determinations and emissions limits for Units 1 and 2 of Roseton. It is also disapproved New York’s SO2, NOX and particulate matter PM BART determinations and emissions limits for the coal-fired Unit 4 at Danskammer.

For Danskammer Unit 4, the FIP limits are:

  • 0.12 lbs/MMBtu of NOx, to be met on a 24-hour average during the ozone season (May through September) and a 30-day rolling average the rest of the year, and a requirement that the owners/operators comply with this NOX BART limit by July 1, 2014.
  • The SO2 BART determination is 0.09 lb/MMBtu, to be met on a 24-hour average, and a requirement that the owners/operators comply with this SO2 BART limit by July 1, 2014.
  • The PM BART determination is 0.06 lb/MMBtu, to be met on a one-hour average, and a requirement that the owners/operators comply with this PM BART limit by July 1, 2014.
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.