Utah developer quadruples battery storage to meet new electricity demand

Here’s one way to accelerate the clean energy transition: quadruple the energy storage projects you’re already building.

Salt Lake City–based rPlus Energies made this move with its Green River Energy Center in eastern Utah. Utility Rocky Mountain Power had awarded a contract from a 2020 proposal for 400 megawatts of solar paired with 200 megawatts/​400 megawatt-hours of energy storage — a substantial battery, to be sure.

But since then, electricity demand has switched into major growth mode to supply data centers, AI and electrification of vehicles and buildings. To deal with that, the utility asked for more from the Green River project. RPlus complied, and earlier this month, it announced it had amended its contract to include 1,600 megawatt-hours of storage capacity, four times the previously agreed-upon amount. It’s an unprecedented leap for a large-scale grid storage project, and it says a lot about the crucial storage market’s propulsive new era.

“This really gives [Rocky Mountain Power parent company] PacifiCorp the ability to have a large dispatchable system. […] It becomes effectively a 400-megawatt peaker plant,” rPlus President Luigi Resta told Canary Media.

Storage plays an essential role in taking the ups and downs of renewable power production and turning it into a dependable, on-demand power flow. For years, though, the promising climate solution languished as a sideshow to wind and solar. That has changed: In 2024, the U.S. will install more battery capacity than gas and wind plants combined. Texas will singlehandedly install as much battery capacity as the whole country did last year.

This sudden battery surge results from new players entering the market and seasoned developers building bigger than they have before. RPlus falls into the latter category. The company, which also develops pumped-hydro storage, first applied for grid interconnection for the Green River project in 2016, seeking to inject up to 400 megawatts of clean power onto a 345-kilovolt transmission line in eastern Utah. At the time, the idea was to fill in where generation from aging coal plants was expected to decline, Resta said.

Later, rPlus modified the interconnection request to include battery storage, which the utility selected in its 2020 call for proposals. Then, at the end of 2023, rPlus needed to modify its completion timeline based on lingering delays from the Covid-era supply-chain disruptions, Resta said, and that’s when PacifiCorp asked for even more storage.

Several factors worked in the project’s favor. Having a utility and a private developer aligned in their motivation to enlarge a clean energy project makes a difference. It also helped that rPlus had already staked out enough space to install a much larger power plant.

“We had always planned on the project being larger — we already had the land,” Resta said.

Crucially, the quadrupling of storage capacity did not trigger any onerous new transmission-grid upgrades, which could have incurred punishing costs and delays. Grid planners were already expecting the site to inject 400 megawatts of power at a time, and that won’t change. The expanded storage capacity just means the project can keep delivering that power for more hours of the day. Resta likened this to pulling cars off the freeway at rush hour and sending them through at times when the roads are less jammed.

RPlus was able to pull off the more ambitious project in part because it recently received an investment of up to $460 million from Sandbrook Capital, an energy-focused private equity investor. That funding, part of a broader trend of financiers warming up to the battery storage category they once considered risky, secured the resources necessary to get started on increasingly large and capital-intensive clean infrastructure projects. The Green River project is expected to cost more than $1 billion to build; construction will begin in the second quarter of this year.

Electricity demand growth across the country has turned into a ​“hockey stick going up,” Resta said; dealing with this generational challenge will require more collaboration like that which took place with Green River.

“The utilities and developers are going to have to start working together to see how fast we can responsibly develop projects and deploy them,” Resta said.