Utah’s solar power landscape has taken another giant step forward.
The Green River Energy Center, a project in Emery County developed by Salt Lake City-based company rPlus Energies, began operations this week. It is an 800-megawatt colossus, with 400 megawatts of solar generation and 400 more in battery storage.
“It’s a big deal,” rPlus Chief of Staff Theresa Foxley said. “The state of Utah most days has a load, or demand, of about four gigawatts, so this project at any given time could be satisfying about 10% of Utah's load.”
That’s enough electricity to power some 110,000 homes, Foxley said, making it the largest solar and battery operation not only in Utah, but in Rocky Mountain Power’s six-state footprint. The utility and rPlus now have a 20-year agreement to send power to homes across the state, including Salt Lake City.
Adding this much more power also helps combat rising electricity costs, Foxley said. The state’s residential electricity prices have increased nearly 15% in the past two years, according to the U.S. Energy Information Administration.
The project is another sign of the momentum clean energy is gaining in the Beehive State. 2025 was a banner year for solar in Utah, and renewables now generate nearly a quarter of the state’s electricity. Solar represents virtually all the new power added to Utah’s grid since 2015.
Because the Green River project pairs solar with battery storage, it isn’t solely dependent on daytime sunlight. And its turnaround time from breaking ground to generating power in less than two years is fast for any electricity source of this size, said Jennifer Eden, senior associate of climate and clean energy with advocacy group Utah Clean Energy
“It's just an example of what kinds of things can be done with renewable energy,” Eden said, “in terms of speed, in terms of scale and in terms of cost-effective investments.”
The benefits extend far beyond Utahns’ monthly bills. Reducing fossil fuel emissions is a vital step in curbing climate change, which already impacts Utah with more frequent, more intense heat, drought and fires.
Fuel-free power also offers more energy independence, Eden said. That’s because it is not subject to the whims of market prices, disasters or geopolitical situations, such as the U.S. war with Iran.
“It's a no-brainer,” Eden said. “We have land. We have sun.”
The Green River project also shows a potential path forward for the transition from fossil fuels to renewable energy, even in areas that have traditionally produced oil and gas.
Emery County is prime solar power country, Foxley said, with plenty of sunny days and powerful high-elevation radiation. The fact that it has nearby access to power transmission lines originally built for the county’s Hunter and Huntington coal-fired plants makes it an even better fit.
“This project is so harmonious with the existing assets that are already in this community and that have powered the state of Utah for generations now,” Foxley said.
And renewable projects can still benefit those communities, she said. The Green River project has contributed $375,000 in student scholarships, according to rPlus, and will pay $55 million in county property taxes over the next two decades.
Because the project was built on private land, Foxley said it also provides income for the land owners to weather the ups and downs of agriculture. In this case, that’s a ranch that is leasing some of its unproductive grazing land.
“Now, they get a consistent stream of revenue that really allows them to help invest in other aspects of the ranching operation to become more productive, more efficient,” Foxley said.
While the Green River project was not cheap — construction cost approximately $1.1 billion — the plummeting cost of solar and battery materials makes massive plants like it more feasible.
Solar panel prices have dropped around 85% since the early 2000s, according to research from Harvard University and the University of Pennsylvania. Analysis from Bloomberg says battery costs dropped 45% between 2024 and 2025. That means solar and battery systems can now deliver electricity at a similar cost to coal and gas plants.
Battery prices will likely continue to fall as cheaper chemistry combinations like sodium-ion batteries become more common, said Logan Mitchell, a climate scientist and energy analyst with Utah Clean Energy.
“Salt is a lot cheaper than lithium,” Mitchell said. “So, I expect to continue to see declines in battery prices well into the future.”
Advancements in technology can help Utah harness solar power more effectively, said Emy Lesofski, who directs the Utah Office of Energy Development, and get the state closer to achieving its energy goals. Gov. Spencer Cox’s Operation Gigawatt aims to double Utah’s production of reliable energy over the next decade.
"When we say we are an ‘any of the above’ state, we mean it,” Lesofski said in a statement. “Utah is committed to fostering a diverse system of affordable, sustainable and dispatchable power, and the Green River Energy Center project delivers on this commitment.”
There are some concerns that the Trump administration’s policies targeting renewable energy could thwart its momentum. Rocky Mountain Power’s parent company, PacifiCorp, is pulling back from future renewable projects, largely because of the administration’s actions to undo Biden-era tax credits.
But even without those incentives, Mitchell said, the market is already pointing toward more solar.
“It's a bummer to see those go away, but even after they go away, it's still the most cost-competitive energy out there,” Mitchell said. “These kinds of projects will still be built; we're just going to have to pay more for them.”
