In October, Ameren Energy Resources announced the closure of two Illinois coal plants, citing impending EPA regulations as the reason.

As we noted at the time, while the EPA rules were likely the precipitating factor leading to closure, the power plants were among the oldest and most expensive to run in Ameren’s fleet, and were on their last legs anyway.

But now, it seems the closures may have actually saved Ameren money.

SNL Financial (subscription) reports that in a conference call to investors today, Ameren CEO Thomas Voss said the closures of the Meredosia and Hutsonville plants will help the company avoid $70 million in emissions upgrades.

Here’s why: While the plants are shutting down, Ameren will retain their emissions allowances for sulfur dioxide and nitrogen oxide for another three years. This enables Ameren to cut back on proposed emissions upgrades for the Edwards power plant in Illinois, still updating the plant for particulate controls but eliminating “baghouses” needed to reduce SO2 and NOX.

“So, I’d say the CSAPR rules were certainly the cause of the decision to shut down Meredosia and Hutsonville, but that did lead to a chain of decisions that led to reduced capital costs at our Edwards facility,” Voss told investors, according to SNL.

Ken is the director of the Energy News Network at Fresh Energy and is a founding editor of both Midwest Energy News and Southeast Energy News. Prior to joining Fresh Energy, he was the managing editor for online news at Minnesota Public Radio. He started his journalism career in 2002 as a copy editor for the Duluth News Tribune before spending five years at the Spokesman-Review in Spokane, Washington, where he worked as a copy editor, online producer, features editor and night city editor. A Nebraska native, Ken has a bachelor's degree from the University of Nebraska-Lincoln and a master's degree from the University of Oregon. He is a member of the Society of Professional Journalists and Investigative Reporters and Editors.