MEMORANDUM
SUBJECT: Environmental Protection Agency (EPA) visit to Great River Energy (GRE) Coal Creek Station (CCS)
FROM: Aaron Worstell, EPA Region 8, Air Quality Planning Unit
TO:  Docket EPA-R08-OAR-2017-0486 for North Dakota regional haze SIP/FIP revision
DATE: October 2, 2017
The EPA visited GRE's CCS power plant on September 27, 2017 for a site tour. The EPA staff (Jaslyn Dobrahner, and Aaron Worstell) were accompanied by staff from the North Dakota Department of Health (NDDH). 
Pre-tour Meeting
Prior to commencing the tour, EPA and NDDH staff met with Great River Energy representatives in a meeting room at about 9:00 am. The EPA stated that the purpose of the visit was to learn more about the operation of CCS as EPA begins review of North Dakota's January 2013 supplemental SIP.  EPA stated that, in particular, the purpose of the visit was to learn about existing NOx controls, and recent reductions in NOx emission at CCS.  
GRE explained that while additional combustion controls (referred to as LNC3+, or low-NOx burners with close-couple overfire air and separated overfire air with larger registers) were installed on Unit 2 in 2007, Unit 1 is currently only equipped with LNC3.  GRE stated that, as there currently is not a BART requirement for either unit, they are awaiting EPA action on North Dakota's 2013 supplemental SIP before investing in any additional NOx controls.
EPA inquired about the reason for a reduction in NOx emissions at both of the CCS units since about the beginning of 2017.  GRE explained that the reduction was due to a change in coal quality, and to a lesser degree, MATS controls.  In particular, GRE noted that higher sodium content in the lignite coal mined at the adjacent Falkirk mine had led to a buildup of deposits on the boiler tubes that had in turn led to lower NOx emissions.  However, GRE noted that the characteristics of the coal may not remain the same in the future and that, therefore, the recent lower NOx emission levels may not be sustainable. 
GRE emphasized the importance of their fly ash business, and of the environmental benefits of not landfilling the fly ash.  GRE also emphasized their continued commitment to environmental stewardship.
Plant Tour
After donning personal protective equipment, EPA, NDDH, and GRE staff visited the following locations in the plant:  coal preparation (including DryFining), coal-firing, overfire air ports, ash handling, electrostatic precipitator, and turbine floor.
The visit concluded at about 11:30 am at the office building.
