Power from above instead of below: Utah’s largest solar project comes to coal country

‘Green River Energy Center’ will supply electricity even when the sun is down.

(rPlus Energies) The developers of this solar farm near Wellington, Carbon County, have announced plans to build a bigger solar plant with battery storage in neighboring Emery County.

This story is part of The Salt Lake Tribune’s ongoing commitment to identify solutions to Utah’s biggest challenges through the work of the Innovation Lab.

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A Utah company has announced an agreement with PacifiCorp to build the state’s largest solar farm and battery storage facility in the heart of Utah’s coal country.

rPlus Energies and Rocky Mountain Power parent PacifiCorp signed an agreement for PacifiCorp to purchase the power generated by a 400-megawatt solar farm and associated 200-megawatt battery storage facility. The $750 million “Green River Energy Center” will occupy about 3,200 acres of private property north of the small Emery County town of Moore.

Emery County offers two advantages: sunshine and transmission lines. The transmission lines are there because PacifiCorp’s Hunter and Huntington coal-fired power plants are the single biggest sources of electricity for Utahns.

The addition of battery storage addresses the limiting factor on solar energy: it stops producing when the sun goes down.

“To me, what it [battery storage] does is it makes solar more valuable,” said Emery County Commissioner Kent Wilson, who noted there is so much solar power in the Western U.S. now that “you can’t give it away” in the middle of the day.

Wilson said the county, Emery School District and other taxing entities have negotiated a tax incentive with rPlus that will reduce the company’s tax burden for the first 20 years but also will provide funding for affordable housing. The land is currently used for grazing, so the project will dramatically increase the tax revenue from that property.

“For Emery County, the solar projects will give us roughly $10 million over a 20-year history to address our affordable housing needs,” he said.

Those solar projects include the Green River Energy Center but also others PacifiCorp is pursuing under a request for proposals for 1,200 megawatts of renewable energy, including 652 megawatts of battery storage.

Utah's largest solar farm and battery project will sit on 3,200 acres north of Moore in Emery County.

“Emery County has been an energy community for a long time,” said Luigi Resta, President & CEO of rPlus Energies, which is a subsidiary of the Gardner Group, the real estate development company founded by Kem Gardner. “With the Huntington and Hunter plants due to reach end of useful life over the next 10 to 20 years, the fabric of the county is rapidly transforming. The Green River Energy Center continues the legacy of pioneering change and discovery in the region.”

For comparison, the Hunter plant has a capacity of 1,372 megawatts, and Huntington’s capacity is 909 megawatts. So with the addition of 200 megawatts of storage, the Green River project will continuously produce less than 10% of what those plants can make when it’s dark.

Because PacifiCorp has multiple power sources across six states, adding the Green River plant doesn’t directly affect how much the big coal plants will produce, said PacifiCorp spokesperson David Eskelsen. “All of the resources of the company go into a big pool.”

The Hunter plant’s output, he said, is already ramped up and down as the cheaper, cleaner solar power becomes available during the day.

Eskelsen said PacifiCorp is negotiating with other companies for possible projects in Emery County under that same request for proposals, which has also brought in wind projects in Idaho and Wyoming.

Sundt Construction will be the contractor on the project. Sundt has offices across the West including in Salt Lake City, and the project is expected to employ 400 people during construction. After the plant is built, a smaller number of permanent employees will keep it running. Construction is expected to begin next year, and the plant will be operational in 2025.

Tim Fitzpatrick is The Salt Lake Tribune’s renewable energy reporter, a position funded by a grant from Rocky Mountain Power. The Tribune retains all control over editorial decisions independent of Rocky Mountain Power.