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Baghouse Bottleneck

EPA, mercury and electric reliability.

Fortnightly Magazine - February 2012

only in 2017, and returning to the required 15 percent only in 2018. Yet the problem goes way beyond reserve margins, as reliability is location-specific and involves deliverability and voltage stability issues that sometimes must be resolved by transmission upgrades, which can take much longer to plan, permit and construct than pollution controls at generating plants.

The problem is rather a matter of timing, as the new EPA rules force hundreds of plants to undergo retrofits and planned outages—all more or less at the same time.

Testifying at the FERC conference, Southern CEO Topazi envisioned four-and-a-half to five years to install a scrubber:

“The fastest we’ve ever installed one is 40 months. The longest is 69 months. Our average is 54 months.”

AEP CEO Nick Akins agreed, suggesting 50 to 60 months to go through the regulatory approvals, permitting, engineering procurement, and actual construction:

“We have spent $7.2 billion replacing scrubbers…

“You really have to understand, it is not just a box you stick on the back of a tailpipe.”

Then there’s the challenge of orchestrating and choreographing outage periods, which Akins estimated at between 15 and 20 weeks for a 50- to 60-month scrubber installation. That requirement, coupled with real-world issues such as construction cycles and supply chain management, led Akins to predict that, “for our system, it would take until 2020 to get this done.”

Back at Southern, Topazi saw the construction of the baghouse—the building containing tubes of fabric filters to remove particulates, as a complement to the scrubber—as the critical driver:

“About 15 to 17 is our estimate of what we have to install… By the end of 2015, we’d have three or four completed.

“Keep in mind,” he added, “you take a coal plant that has four units, and we’re talking about a baghouse for each one of those units in a confined space. You physically can’t do all four simultaneously … we’ve had to shoehorn scrubbers and SCRs [selective catalytic reduction] into the plant itself … or you have to do what we had to do at our plant Scherer—build a baghouse a quarter-mile away, and then duct and force air to make it fit.”

Claire Moeller, v.p. for transmission asset management at MISO, assumed that at any one time his region could afford to take out only about 15,000 MW of some 60,000 MW in coal-fired units undergoing retrofits: implying that MISO would need “between three and six outage windows,” requiring at least two to three years.

“Just to think about it,” added Moeller, “we as a nation are going to have something like 100,000 MW of steam plants order a baghouse on the same day—because they all have the same compliance clock.”


Hobson’s Choice

The Clean Air Act dictates a three-year deadline for MATS compliance following publication of the final EPA rule in the Federal Register , with EPA authorized to grant a one-year extension. Yet the studies and the anecdotal evidence reported at the conference suggested that compliance will take much longer. To ease the pressure, the power industry has embraced two