Air Enforcement: Alabama Department of Environmental Management and Mobile County Electric Generating Facility Enter Consent Order | Mitchell, Williams, Selig, Gates & Woodyard, LLC


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The Alabama Department of Environmental Management (“ADEM”) and the Alabama Power Company (“APC”) entered into a Consent Order (“CO”) on January 3 regarding alleged violations of a Major Source Operating Permit (“Permit”).

The OC provides that APC will operate an electrical generating facility (“Facility”) in Mobile County, Alabama.

It is stated that the facility includes a coal-fired electric boiler operated under the authority of the permit.

Emission Standard No. 8 of the Covenants for the Unit 4 Electric Boiler Section of the Permit states the following:

The HCl emission rate must not exceed 0.0020 lb/MMBtu. 40 CFR 63.9991(a)(l)

The CO states that on August 4, 2021, APC conducted an HCl emissions test on Unit 4 in accordance with Method 26 of 40 CFR 60, Appendix A.

ADEM would have received on August 30, 2021 a report from APC summarizing the results of the previously referenced test. The test would have indicated a measured HCl emission rate of 0.0023 lb/MMBtu, which exceeded the applicable HCl emission limit.

APC supports in CO:

  • It operates a dry powder hydrated sorbent injection system for acid gas control in Unit 4.
  • Since 40 CFR Part 63, Subpart UUUUU also requires control of particulate emissions, Unit 4 avoids over-injection of powdered sorbent, especially at higher loads. To this end, the incumbent worked diligently with internal and external industry experts to develop an injection rate curve that would define the correct amount of sorbent to inject at a given load to effectively control gaseous emissions. acids.
  • Less sorbent is needed at lower loads compared to higher loads to provide the same control efficiency because less fuel is consumed. In order to provide additional control efficiency and compliance margin at lower loads, Unit 4 injects relatively higher amounts of sorbent per pound of fuel compared to higher loads.
  • After receiving the results of the preliminary tests, unit 4 was taken offline and ADEM was informed of the overrun and a new test was scheduled.
  • A report summarizing the final results was submitted indicating a measured HCl emission rate that was well below the applicable HCl emission limit.
  • An investigation was conducted which indicated that the control system was functioning properly in all respects and was in compliance with control operations which had previously resulted in compliant stack tests for HCl. (The investigation would also have revealed that the constituents of the delivered coal varied from historical ranges.)
  • It is stated that the previously mentioned changes upset the balance in Unit 4 and it is likely that operations at lower loads did not result in any exceedances of the applicable HCl limit.
  • The injection rate was adjusted to accommodate the wider range of coal constituents and re-tested at full load.

APC neither accepts nor denies ADEM’s assertions.

A civil penalty of $75,000 is imposed.

A copy of the CO can be downloaded here.


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