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Selective Catalytic Reduction Optimization

Colbert, Cumberland, Kingston, Paradise, and Widows Creek Fossil Plants

Alabama, Kentucky, and Tennessee

On April 30, 2008, TVA completed a final supplement to an environmental assessment (EA) and issued a finding of no significant impact on the operational improvements to optimize selective catalytic reduction (SCR) systems at five fossil plants in Tennessee, Alabama, and Kentucky.  Both of these documents may be viewed online by accessing the links below.

The proposed changes would optimize the operation of 17 systems installed at the five plants by enabling TVA to sustain high nitrogen oxide (NOx) removal rates while extending the SCR catalyst life until the next scheduled outage.  This would be accomplished by increasing slip up to values that do not cause violations of applicable opacity standards, water quality criteria, National Pollutant Discharge Elimination System action levels, or toxicity reference values based on constraints at the individual plants.  Slip is the ammonia that passes through the SCR without being converted to innocuous nitrogen compounds.

The EA supplements several reviews issued by TVA for the original installation of the SCR systems, as well as an EA issued by TVA in 2005 on SCR catalyst replacement.  Some of these documents are available at the links provided below.


PDF files require Adobe Acrobat Reader.

Finding of No Significant Impact (PDF, 119 kb)
Final Supplemental Environmental Assessment (PDF, 1 mg)

Related Environmental Assessments:

Replacement or Rejuvenation of Catalyst for Selective Catalytic Reduction Systems at Seven TVA Fossil Plants

Colbert Fossil Plant NOx Reduction System

Kingston Fossil Plant NOx Reduction System


For further information, contact:
David W. Robinson, Senior NEPA Specialist
NEPA Resources
Tennessee Valley Authority
1101 Market Street, LP 5U
Chattanooga, TN 37402
Phone:  423-751-2502; Fax:  423-751-3230