The Colorado Public Utilities Commission on Monday approved a $2.5 billion plan by Xcel Energy to close coal-fired power plants and add a hefty dose of wind and solar generation so that 55 percent of the utility’s electricity will come from clean energy by 2026.

Xcel, Colorado’s largest electricity provider with 3.2 million customers, got the OK from regulators to close two units at its Comanche Station in Pueblo 10 years ahead of scheduled as part of its Colorado Energy Plan.

The units, with a total of 660 megawatts (MW), will be closed by 2026. A third Comanche unit will continue to operate.

Switching from coal-fired electricity to cheaper wind and solar will save customers around $200 million by 2054, according to company and PUC estimates.

“Retiring Comanche 1 and 2 sooner rather than later is the right thing to do,” said Commissioner Frances Koncilja.

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Xcel will add 1,110 MW of wind power, 700 MW of photovoltaic solar and 275 MW of energy storage tied to solar projects. The utility will also purchase 383 MW of existing natural gas turbines as back-up.

“This is the first time in the nation that a utility is proposing closing coal-fired plants and replacing them totally with renewable energy,” said Erin Overturf, an attorney with the environmental policy group Western Resource Advocates. “It reasserts Colorado’s standing as a leader in clean energy.”

When Xcel called for bids for new wind and solar projects, it received more than 400 responses with some of the lowest quotes for power in the country. Commission Chairman Jeff Ackermann called it “a rare opportunity.”

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The Colorado Energy Plan was proposed by Xcel in 2017 and drew support from environmental and business groups, independent power producers who sell electricity to Xcel, unions and consumer advocates.

“We value the partnership with our stakeholders who supported this plan and its approval,” Alice Jackson, president of Xcel Energy-Colorado, said in a statement. “We also recognize the diligent work of the commission throughout the process and appreciate the decision reached today. We are excited to move forward.”

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Xcel had initially sought to own 50 percent of the new generating capacity, but under the proposed plan will own just 27 percent of the renewable resources and 58 percent of the natural gas generation.

The utility will purchase the rest through long-term contract with power project developers. “Xcel has left money on the table for independent power producers,” Koncilja said.

Closing the two coal units will help Xcel reduce its system-wide emissions of sulfur and nitrogen oxides by 90 percent by 2026 and its emissions of carbon dioxide, a greenhouse gas, by 60 percent.

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“Today’s deliberation indicates a significant step forward for decarbonization efforts and clean energy development in Colorado, and the plan is a clear rebuttal to the notion that we have to choose between affordable electricity rates and clean air,” said Zach Pierce, a spokesman for the Sierra Club’s Beyond Coal campaign.

The commission also approved a financing method for paying offing the accelerated depreciation for closing the two Comanche units.

Two percent of customer bills now goes to a renewable energy fund that has financed solar projects. Starting in 2021 half of that money will go to fund closing the coal-fired units.

The Coalition of Ratepayers, a group back by the libertarian Independence Institute, raised a series of critiques on Xcel’s accounting and modeling techniques in valuing the benefits of the clean energy plan that the PUC adopted in its evaluation, although it decided that there were still significant savings in the plan.

“We appreciate the Commissioners’ complimentary statements regarding our work and glad we intervened to be the voice of those who must pay the bill,” said Amy Cooke, director of the coalition and executive vice president of the Independence Institute.