On Feb. 23, Mirant's Potomac River Generating Station (PRGS) registered an exceedance at one of its sulfur dioxide (SO2) monitors — 11 percent over the permissible standard.
That fact is the only thing all parties involved in the detection and reporting of the incident can agree upon.
In an e-mail dated Feb. 26 to William Skrabak (division chief, Environmental Quality, Alexandria Transportation & Environmental Services Administration) and Elizabeth Chimento (Mirant Community Monitoring Group), Jeffery Steers (regional director, Virginia Department of Environmental Quality [DEQ]), stated:
"DEQ was notified today that on Friday 2/23 Mirant experienced a MONITORED exceedance of the 24 hour SO2 NAAQS (National Ambient Air Quality Standards) at its southeast fence line monitor."
Steers said the plant was operating all five units between 75 percent and 100 percent capacity last Friday under the U.S. Department of Energy Order's Line Outage provision. "PEPCO had taken the two transmission lines feeding the plant from under the Potomac River out of service to conduct scheduled maintenance and other work," according to Steers. "None of the five other SO2 monitors surrounding the plant indicated readings approaching the NAAQS and the southeast monitor did not indicate an exceedance of the 3-hour SO2 NAAQS."
The plant will be operating under DOE's Line Outage provision through March 6, Steers informed Skrabak and Chimento.
The primary disputes over the occurrence that day is over who knew what, and when; as well as whether modeling of a "worst case scenario" compared to monitoring only would be more effective.
ON THE MORNING of Feb. 23 DEQ Air Compliance Inspector Justin A. Wilkinson made an unannounced site visit to the Mirant facility. His purpose was to "review continuous emissions monitoring (CEM's) data and inquire about current and future operations of the PRGS."
While meeting with Michael Stumpf (group leader, plant operations, PRGS), Wilkinson was informed that the exceedance had occurred at the southeast monitor, according to William Hayden, (public information officer, DEQ).
Feb. 23 was a day of high and shifting winds. In his report, Wilkinson said, "Mr. Stumpf explained that the recent data collected during this sustained shift in winds, is close to what the modeling would predict. He explained that the weather pattern that the facility is currently experiencing, is close to what the modeling calls a "worst case scenario."
This report caused Poul Hertel, also a member of the Monitoring Group, to inquire, "So what about all the other points where there are no monitors?"
ON TUESDAY, FEB. 27, Mirant Corporate Communications Manager Felicia Joy Browder issued a press release stating, "Mirant Corporation's Potomac River Generating Station measured a small, limited exceedance at one of its SO2 monitors on Friday, February 23rd. After reviewing the monitoring data, Mirant notified all relevant federal and state agencies as well as the City of Alexandria of the occurrence."
Both Browder and Debra Bolton, vice president and assistant general counsel for Mirant, insisted in a telephone conversation from Mirant headquarters in Atlanta, GA, that it was Mirant who took the initiative in announcing the exceedance. "I was the one who alerted everyone," Bolton said.
Browder also verified that the PRGS was operating under DOE emergency procedures. "Under these provisions, the federal government requires the plant to operate as directed by PJM to prevent blackouts." PJM Interconnect is the regional electricity manager for the grid.
PRGS was operating all five units "to help assure reliability to the grid," according to Browder. "Winter storm conditions and high winds had caused regional outages. Under non-emergency normal operating procedures that have been followed by the plant for the last 9 months, PRGS would have reduced its operations to ensure that under no circumstances would any NAAQS limitation be exceeded," Browder stated in her news release.
Browder said the "one-time exceedance" would not have occurred if Mirant's stacks "were higher or internally reconfigured."
Skrabak sees last Friday's incident and the ultimate solution somewhat differently. "Modeling is the appropriate tool. The model
is actually closer to reality than [Mirant wants] to admit," said Skrabak, who hopes to bring the situation to the attention of the State Air Pollution Control Board.
"The City has two goals when it comes to Mirant — clean it up in the short term and close it down in the long term. We are working with regulators to get it cleaned up. And, as a show of good faith we have put our nuisance suit on the back burner for now," he said.
Whether Mirant alerted all other parties to the February exceedance or whether it was brought to the attention of the DEQ inspector on site at the time and transmitted by him to DEQ and the City remains a point of disagreement.
The fact that it occurred is not.