The uninterruptible power supply has been a fixture of data center design for decades, prized for both power conditioning and resiliency. But according to a report from Data Center Knowledge, that central role is being challenged from both ends of the power chain: AI-driven densification on the load side, and growing use of renewables, microgrids, and on-site generation on the grid side.
UPS Failures Are a Leading Cause of Outages
The Uptime Institute’s Annual Outage Analysis 2026 found that power-related issues caused more than one in five IT service outages over the past three years. Within those incidents, UPS failures were the single leading cause at 39%, ahead of transfer switch failures (34%) and generator failures (28%). Uptime Institute research also points to lithium-ion batteries in UPS systems as a contributing factor in a gradual rise of major data center fires, though it notes the increase may partly reflect rapid new facility build-out rather than inherent battery risk.
AI Workloads Are Changing What UPS Systems Must Handle
Speaking at the Data Center Event in Budapest on September 29, 2026, Socomec’s Luka Grahek said AI loads are introducing short, intense power bursts and increased harmonic distortion that traditional UPS systems were not designed to manage. He pointed to the cyclicity of AI workload demands as a particular challenge.
Dell’Oro Group’s Alex Cordovil described how large training clusters can swing power demand by tens of megawatts within seconds, effectively reversing the UPS’s traditional function. Rather than protecting IT load from the grid, the UPS increasingly needs to protect the grid from the IT load. Cordovil noted the UPS has repeatedly been declared obsolete, only to reappear in new forms.
Distributed Architectures and BESS Offer Alternatives
Hyperscale cloud operators have long used Open Compute Project-style distributed or rack-level UPS designs with battery backup units, and the rise of 800V DC architectures and sidecar power cabinets in AI factories is extending that distributed approach to handle extreme rack densities.
Battery energy storage systems (BESS) are also emerging as a parallel resiliency path. While not a direct UPS replacement, BESS can let operators right-size or even eliminate centralized UPS systems. In 2025, BESS supplier FlexGen Power Systems and contractor Rosendin announced a partnership to develop utility-scale BESS configured as interactive UPS alternatives, aimed at reducing electrical footprint and construction complexity while improving efficiency and resiliency.
What It Means for Operators
The shift suggests the UPS may evolve from a purely resiliency-focused device into more of an energy hub involved in broader power-quality management. For hosting providers and data center operators, the key takeaway is that power architecture decisions are no longer just about backup time, they increasingly need to account for AI-driven load volatility and the growing role of distributed and battery-based alternatives.