PacifiCorp's recently announced plan to retire nearly 2,800 MW of coal-fired generation by 2030 and nearly 4,500 MW by 2038 to make way for renewable energy and battery storage capacity could undercut the coal sector's argument that the fuel is necessary for reliable energy generation.

The plan will hurt several western coal producers, with the bulk of the impact falling on rural communities where a coal mine may not have another customer, experts said.

PacifiCorp announced its preferred portfolio on Oct. 3, which includes adding more than 7,000 MW of solar, wind and battery storage, as part of an integrated resource plan. Under the draft resource plan, the power company intends to move up the retirement date for Jim Bridger unit 1 from 2037 to 2023; Jim Bridger unit 2 from 2037 to 2028; Naughton units 1 and 2 from 2029 to 2025; Craig unit 2 from 2034 to 2026; and Colstrip units 3 and 4 from 2046 to 2027, according to a company release. In total, 16 of its 24 coal units are expected to come offline by 2030, increasing to 20 units by the end of 2038.

Robert Godby, director of the Center for Energy Economics and Public Policy at the University of Wyoming, said in an interview that he has been on the company's public input calls since January and was not surprised by the announcement. Several studies revealed that these units were the most costly, so it stands to reason that they would be considered for earlier retirement, he said.

He noted that PacifiCorp is only a partial owner of several of the power plants.

"It's not so much saying that they will retire those plants, as if it were a choice that PacifiCorp were making, as much as admitting that those plants may go offline anyway because of the decisions other operators are making," Godby said.

These plant closures have the potential to "decimate" some local economies where the affected plants and the mines that feed them are located, he said. But the impact to overall western coal production will likely be less significant.

"But with respect to total coal production in the West ... the changes that are really driving coal production changes out here are all due to plant decisions being made in the East or in Texas, quite far away, and that's really the nature of the market," Godby said. "So, 2,800 MW [coming offline] is a lot, but it pales in comparison to the amount of production going out of the Powder River Basin."

The West is starting to mirror what has happened in the East in terms of coal-fired generation coming offline due to market competition from other generating sources and regulatory uncertainty, he said. Many western coal plants operate inside regulated utilities where closing a generator may require an increase in ratepayer cost in the short term, a largely unpopular move.

"Renewables, wind, solar and even storage have gotten to the point where even under a regulated utility, you can't ignore them anymore," Godby said.

Ian Lange, director of the Colorado School of Mines' mineral and energy economics program, said battery storage is about to hit the market, which may have a "domino effect."

"You don't have this argument that these renewables are intermittent because you have the batteries to back them up," he said.

The coal sector has argued that the fuel's resiliency makes it all the more important to keep it in the nation's energy generation mix, given the intermittent generation from renewables resources. Stan Dempsey Jr., president of the Colorado Mining Association, noted that the state is moving away from a "very solid, predictable set of infrastructure" in favor of emerging battery storage technology. Utilities are under "extreme pressure" by state governments to transition to cleaner energy sources, he said.

He also pointed out that some of the other power plants' co-owners have not necessarily agreed to the earlier retirement dates. The Grand Junction (Colo.) Daily Sentinel reported on Oct. 4 that Tri-State Generation and Transmission Association Inc., which is a co-owner of the Craig power plant, said there has not been a decision made by all owners to retire Craig unit 2 early.

Clark Williams-Derry, director of energy finance for Sightline Institute, a sustainability think tank, said renewables coupled with storage will continue to out-compete coal and noted that the declining cost of storage damages the coal industry's resiliency argument.

"The fundamental reason why PacifiCorp wants to shut its coal-fired power plants is that it's cheaper for them to do it that way," the director said. "It's cheaper for them to develop wind and solar resources and storage than it is to keep old coal-fired power plants running. That economic reality is not going to go away anytime soon."

The Jim Bridger and Naughton plants will have "pretty big effects on southwestern Wyoming," Williams-Derry continued. Westmoreland Mining Holdings LLC's Kemmerer mine is largely dependent on the Naughton plant while Lighthouse Resources Inc.' and Anadarko Petroleum Corp.'s Black Butte and Leucite Hills mines will be affected by the Jim Bridger closure.

Looking at all the plants slated for closure over the next 20 or so years, the Powder River Basin "does not do all that well either," Williams-Derry said.

"You've really got a number of PRB mines that are taking a hit," Williams-Derry said. "Across the board, this thing affects demand for coal all across the U.S. West. In coal country from Montana down through Arizona there are going to be impacts from these closures. It's another blow in some ways to the western coal industry. ... It's part of the continuing saga of the financial and economic decline of coal."

Bob Gravely, spokesman for PacifiCorp, said in an email that the underground Bridger coal mine is scheduled to close in late 2021 as it is depleted, and the Bridger surface mine is slated to close in 2028. Those dates were previously settled, so they will not be affected by the integrated resource plan.

Wyoming passed a law earlier this year that requires investor-owned utilities to try to sell coal plants before closing them.

"Wyoming is the only state with such a law and we will comply with any requirements required by the state prior to closure and reclamation," Gravely said.