ON.energy Tests Medium-Voltage AI UPS
Key Facts
- Testing Location: National Lab of the Rockies (NLR) ARIES platform
- UPS Module Size: 3.5 MW
- Voltage Class: 13.2 kilovolt (kV)
- Load Swing Capability: 70% or more within milliseconds
- Units in Operation or Under Construction: approximately 3 GW
The Problem
AI data centers present significant power grid challenges. IEEE Spectrum reported on April 29, 2026, that these facilities can experience load swings of 70% or more within milliseconds. This volatility is exemplified by a January 15, 2026, ON.energy press release, which noted that individual hyperscale campuses can swing 1 gigawatt (GW) multiple times per minute under current AI workloads. A stark example occurred in 2025 when a Virginia grid fault resulted in a 1.5 GW load drop after approximately 60 data centers tripped offline simultaneously.How the AI UPS Works
ON.energy’s AI UPS is a bidirectional, medium-voltage system designed for hyperscale AI campuses. The product is built using 3.5 MW modules that can scale to the gigawatt range. During testing at NLR’s Flatirons Campus, the unit operated at the 13.2 kilovolt (kV) medium-voltage class, positioned between NLR’s 7 MW grid simulator and a 20 MW load simulator. According to NLR Principal Engineer Shahil Shah, the ARIES platform is one of the few facilities in the Western Hemisphere equipped with both a grid-side and load-side simulator on the same bus, allowing for comprehensive stress-testing. NLR’s March 11, 2026, announcement detailed that the unit absorbed surges from 30% to 100% of its energy capacity at intervals ranging from 10 milliseconds to 1 second.Why It Matters
The increasing demand for grid stability from utilities and grid operators like ERCOT and PJM is a key driver for ON.energy’s product. These entities are now requiring hyperscale operators to demonstrate that their facilities will not destabilize neighboring distribution feeders during rapid power ramp events. ON.energy’s President for the Data Center Division, Dax Kepshire, stated the unit is engineered to help hyperscale data centers “be good grid citizens.” Andrew Hudgins, Acting Program Manager for NLR’s ARIES platform, highlighted that the dual-simulator setup enables ON.energy to stress-test scenarios that would be too risky to replicate on live infrastructure without jeopardizing grid reliability.Critical Perspective
ON.energy reports approximately 3 GW of its bidirectional AI UPS units are in operation or under construction. However, the commercial economics of this pipeline remain . The company has not disclosed specific competitors or price points for its 3.5 MW modules.Related Coverage
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