Crusoe, a major AI data center developer, has placed a 5-gigawatt order for ON.Energy's centralized lithium-ion UPS system, the largest commercial test yet of a technology that fuses grid-scale battery storage with the uninterruptible power supplies data centers have run on for decades. The order follows trials completed earlier this year at the nation's premier grid testing facility, now called the National Laboratory of the Rockies and formerly known as NREL.

The stakes extend well beyond one startup's order book. In July, nearly 4 gigawatts of data center load in Virginia disconnected from the PJM Interconnection grid in a single incident — the kind of sudden demand drop that grid operators say now threatens regional stability. PJM has recorded a handful of such multi-gigawatt drop-offs in recent years.

What does the technology change?

Traditional data center UPS systems are banks of batteries — mostly lead-acid — that sit idle except during emergencies, much like the diesel backup generators almost every facility still runs. ON.Energy's AI UPS instead places a centralized lithium-ion battery between the grid and the entire data center complex, and keeps it working every second of the day.

CEO and cofounder Alan Cooper described the result of roughly a half-decade of development as "the new standard for connecting the data center to the grid." In an interview, he explained the mechanics plainly: "The grid sees a battery that's always charging, and the load sees a battery that's always outputting perfect quality power." The approach, he said, "smashes together BESS" — grid-scale battery energy storage — "and UPS into a single asset."

The engineering hinges on speed. Data center power demand can swing from 5% to 100% in a few milliseconds, according to Shahil Shah, chief engineer at the National Laboratory of the Rockies, who runs the grid simulator lab that tested the AI UPS at multi-megawatt configurations. "You're hammering the grid if you do that," Shah said. Data centers also disconnect the moment grid power quality fluctuates, which produces the massive unexpected demand drops PJM has documented.

ON.Energy's answer is a patented double-conversion design. "Our double-conversion technology, which we've patented, is basically the process of fully electrically decoupling the load from the power generation source," Cooper said. "We're using the fastest-response, best-in-class inverters in the market." From the utility's perspective, he said, the result reads simply: "We're basically a really predictable utility-scale battery that just sits and takes power from the grid."

Who is watching, and why?

Regulators have already moved. The North American Electric Reliability Corp., which oversees the U.S. and Canadian electric systems, has targeted large "computational loads" for new requirements aimed at preventing trip-offs. Texas utility regulators instituted similar requirements this year. Many power system operators, Shah noted, "are coming up with requirements to make sure that the data center loads — the large loads — don't negatively impact the reliability of the grid."

ON.Energy is not alone. Shah's lab is also testing a comparable battery system from Prevalon Energy, along with others he could not yet name.

Built versus promised

The Crusoe deployment has a physical footprint, not just a press release. Cooper showed aerial photographs of a Crusoe campus under construction: the first buildings house traditional UPS systems, while the most recent building has set aside adjacent land for the AI UPS batteries. The system must be designed in from the start; existing data centers cannot simply bolt it on.

Once a facility commits to a centralized UPS, the asset can pay its way twice. A multi-hour battery already justified as a backup and grid-stabilization tool becomes far easier to defend economically for peak-demand reduction or for soaking up excess solar and wind. "You have a battery on site that's multi-hour duration, and you're able to curtail the data center from the grid whenever you need," Cooper said. "It's kind of a natural way to get data center flexibility."

What decides what happens next is the commissioning calendar: the first Crusoe campuses built around the AI UPS, and the NERC and Texas requirements that will determine whether centralized batteries shift from option to obligation for large computational loads.