Dynegy Midwest Generation LLC (DMG), citing a number of alleged deficiencies, on Sept. 21 appealed a construction permit that it had been issued by the Illinois Environmental Protection Agency for a sorbent injection system on the coal-fired Wood River Unit 4.
The appeal of the Aug. 24 permit was filed at the Illinois Pollution Control Board. DMG operates two coal-fired boilers at Wood River, but only one boiler, Unit 4, is the subject of the appealed construction permit. Unit 4, whose principal fuel is coal, fires natural gas as auxiliary fuel during startup and for flame stabilization but can fire natural gas for generation. Certain alternative fuels are permitted to be utilized in Unit 4 as well. Unit 4 operates an electrostatic precipitator (ESP) with flue gas conditioning, as needed, to control PM emissions and, to control NOx, utilizes low NOx burners and over-fired air.
DMG has a longstanding consent decree with the U.S. Environmental Protection Agency that requires air emissions reductions, and applicable provisions in the consent decree must be reflected in permits issued to DMG. Among other things, the consent decree requires Unit 4 to meet a stringent PM emissions limit of 0.030 lb/mmBtu. The consent decree doesn’t, though, require the sorbent injection system that is the subject of this appealed construction permit and so is not a factor in this permit.
Relevant to this appeal, PM emissions from Unit 4 are currently controlled by an ESP with a flue gas conditioning system. The Aug. 24 permit at issue authorizes the construction and operation of a sorbent injection system to reduce emissions of mercury under the state Multi-Pollutant Standard (MPS). DMG opted in to the MPS in November 2007.
“DMG will suffer irreparable harm and the environment will not receive the benefit of the pollution control facilitated by the sorbent injection system if DMG is not allowed to construct and operate the sorbent injection system for Unit 4 at the Wood River Power Station,” the company said. “DMG’s request for stay of the contested language would provide the necessary and appropriate authorizations to install and operate the sorbent injection system in a manner to protect the environment while allowing DMG to exercise its right to an appeal under Section 40(a) of the Act.”
A general problem with the permit is that the Illinois EPA is using this construction permit as the vehicle to improperly implement certain mercury requirements, DMG said. The company went on to cite a number of technical concerns with the permit. It said certain permit conditions exceed the scope of DMG’s request to construct and operate a sorbent injection system.