UPS · Uninterruptible Power Supply
System (battery or flywheel backed) that maintains clean power through grid disturbances and bridges to generators.
Power system that keeps IT load energized through grid sags and outages until backup generation starts.
Also written as: Uninterruptible Power Supply
Current numbers
3–5% vs >99%central UPS: double-conversion loss vs eco-mode / advanced-standby efficiency (Vertiv Liebert EXL S1 datasheet) — a UPS figure, not the ORv3 BBU
~99.999%Google fleet-wide CDU availability since 2020 (redundant pump+HX, UPS-backed)
45%of impactful data-center outages root-caused to power (most often UPS) — the leading single category, down from 54% in 2024