ST. PAUL — Xcel Energy, Minnesota's largest electricity company, will idle two of its coal plants for six months of the year under a plan state regulators approved Wednesday, July 15.

The company has said that operating the plants on a seasonal basis will cut carbon emissions as well as consumer costs. When the company filed its proposal with the state Public Utilities Commission in December, it estimated the move could have saved customers up to roughly $1.5 million in 2020.

"This is an important proposal and I appreciate Xcel Energy bringing it forward," Commissioner Matt Schuerger of the PUC said in a news release. "I think this highlights Xcel’s focus on saving their customers money, on meeting Minnesota’s environmental policies, and in being responsive to the investigation the Commission opened."

It's unclear how the approval of the plan Wednesday affects earlier cost and emissions forecasts associated with it.

Both plants moving to seasonal operation -- the Allen S. King Generating Station in Oak Park Heights and Unit 2 of the Sherburne County Station in Becker -- are already slated to close entirely in the coming years as part of the company's broader plans to wean itself off coal by 2030, with a natural gas plant due to be built in place of the latter. Generating energy for the regional market from June to August and December to February, as Xcel proposed under the plan, would slash greenhouse 7.3 million tons of greenhouse gas emissions in Minnesota by 2023.

The move would seemingly put Xcel on track to meeting the state target for utilities to slash emissions to 30% below their 2005 levels by 2025, according to the PUC.

Xcel had said in earlier filings that it would consult the Midcontinent Independent System Operator, the organization overseeing the transmission grid for the Midwest and part of Canada, and the Federal Energy Regulatory Committee before commencing seasonal operations, though PUC executive chairman Will Sueffert said Wednesday it will not likely require the permission from either to do so. In a statement, Xcel spokesperson Randy Fordice said the utility expects the new schedule to go into effect this fall.

In previous filings, the utility said it would not need to lay off plant workers as it moves toward a seasonal schedule but expects a "reduction in employees through attrition" will accompany its transition to renewable energy sources. Fordice said Wednesday that is still the case, and that the company is "working with employees, communities and other stakeholders to develop specific plans for each area to determine how we can bring new jobs and capital investment to the region."

"We’ve transitioned coal plants in the past, and believe we can do so without layoffs, by normal attrition and job retraining," Fordice said.

In operation since 1968, the King plant can burn approximately 300 tons of coal in an hour — enough to fill two-and-a-half train cars. Like the massive, three-unit Sherco plant, it is outfitted with emission-reducing equipment.