By Robynn Andracsek, P.E., Burns & McDonnell and Contributing Editor

Let’s call a spade a spade. There is a witch hunt right now against coal combustion and the biggest targets are public utility boilers.

In 1977, instead of writing a clear, plain-English law, Congress tried to appease all sides and ended up making the Clean Air Act ambiguous. Environmentalists thought they’d won: Prevention of Significant Deterioration (PSD) would require all new boilers to meet the ever-tightening requirements of Best Available Control Technology (BACT). After all, old boilers would have to be replaced eventually and therefore would end up controlled. Industry thought they’d won: PSD exempted existing “grandfathered” units. After all, existing boilers could be maintained almost indefinitely. As you may have guessed, precisely who wins is all wrapped up in the question of “routine” maintenance, which is exempt from, but never defined in, the PSD regulations.

Tennessee Valley Authority’s (TVA’s) Bull Run power plant illustrates this complex and confusing issue. TVA started operating Bull Run, a 950 MW supercritical, coal-fired utility boiler in 1967. In 1988, in response to historical and anticipated forced outages, the superheater and economizer were overhauled; specifically, the inlet portion of the secondary superheater outlet pendant elements and the economizer elements were replaced. TVA considered this action part of its routine maintenance and did not seek a PSD permit. In 1999, EPA determined the boiler overhaul constituted a “major modification” requiring a PSD permit. A year later, the Environmental Appeals Board (EAB) agreed with EPA. From 2001 to 2010, the case went back and forth in the courts over questions such as statute of limitations, jurisdiction and “fair notice.”

In March 2010, the Sixth Circuit court made its final ruling: the overhaul project was not a “major modification” and qualified as “routine maintenance.” The court applied the WEPCo four-factor test (as did the EAB) and came to a very different conclusion. (The four factors are nature and extent, purpose, frequency and cost.) Since the court ruled the project was a routine exemption, it didn’t take up the question of whether or not there was a significant emissions increase.

Keep in mind there are 300 miles of steel tubing inside the Bull Run boiler. Not surprisingly, boiler tube leaks are the predominant cause of forced outages in the industry since they require immediate repair. The court broke down maintenance into four categories: running, preventative, predictive and reactive or “forced outage.” Boiler tube leaks usually cause forced outages that last for several days.

The Sixth Circuit decision was a victory for the case of “routine” maintenance. The table summarizes the conclusions reached by the court in its ruling.

The Court contrasted Bull Run with two cases that were found as not meeting the test of “routine.” The original WEPCo case was said to be “highly unusual, if not unprecedented, and costly.” The Ohio Edison case involved a “one-of-a-kind spiral tube furnace” whose work order stated the activities were intended to reduce forced outages and improve unit availability and reliability.

The final chapter came in April 2011 when TVA entered into a compliance agreement with the EPA to shut down and control coal-fired boilers in its fleet. As a result, Bull Run is slated to receive a selective catalytic reduction (SCR) system to control of NO_x and a wet flue gas desulfurization (WFGD) to control SO₂.It took 19 years for TVA to win the “routine” maintenance argument and avoid adding control devices, but only one year to end up with those same controls as part of a legal settlement.

It’s this end result that provides the moral for our story. It’s not paranoia if they really are out to get you.