Excerpt from this story from the Wall Street Journal:
An aging, polluting coal power plant in Missouri was headed for retirement this year. But because the region’s grid operator needs the plant’s electricity to reduce the risk of blackouts, it likely will keep running for several years longer.
The push to delay the closure of the Rush Island power plant, a 46-year-old generator south of St. Louis owned by Ameren Corp., shows the difficult decisions that utilities and power grid officials face as projected electricity shortages threaten many parts of the U.S.
The Midcontinent Independent System Operator, or MISO, which oversees a grid spanning much of the Midwest, moved this week to halt Rush Island’s closure this fall. It warned earlier this year that the region faces the risk of rolling blackouts this summer because it might not have enough supplies to meet demand surges on hot days.
The Rush Island plant is one of the country’s largest emitters of sulfur dioxide, and it has long faced criticism from environmentalists, health experts and neighbors because its operations have been linked to health problems in the surrounding community. A federal judge in 2017 determined that Ameren violated the Clean Air Act by failing to install pollution controls before an overhaul of the plant and later ordered the company to do so retroactively.
Ameren estimated that compliance with the judge’s order would cost as much as $1 billion and moved to retire the plant by September in lieu of making the upgrades.
Now, Ameren said in a court filing this week that it likely would have to keep the plant online through September 2025 because MISO determined that closing the plant this year would result in reliability risks. The company said it expects the grid operator to designate the plant as a so-called system support resource, a last-resort measure to ensure adequate electricity supplies during periods of peak demand.