Glossary

PUE

PUE is a common data center efficiency metric. It describes how much energy goes to computing equipment compared with cooling, power conversion, and other facility overhead.

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Definition

PUE stands for power usage effectiveness. It is total facility energy divided by IT equipment energy. A PUE of 1.0 would mean every unit of energy goes directly to IT. Real facilities have overhead from cooling, conversion, pumps, fans, lighting, and controls. Lower PUE means less overhead relative to IT energy.

Why it matters

Energy overhead affects cost and environmental reporting. For AI infrastructure, PUE is important but incomplete. It does not measure whether IT equipment is doing useful work, how clean the electricity is, or how much water is consumed.

A facility with a good PUE can still be inefficient if servers are poorly utilized. A facility with a slightly higher PUE may still be valuable if it is closer to users or uses cleaner power.

How it works

If a facility uses 12 megawatt-hours total and 10 megawatt-hours reach IT equipment, PUE is 1.2. Annualized measurements are more useful than short snapshots because cooling and load change over time.

Published PUE figures are most useful when facilities describe what energy is included and how the number was measured over time. PUE alone does not describe capital intensity, land use, or total operating cost.

Seabase is designing toward approximately 1.05 PUE as a modeled infrastructure target using direct liquid cooling and marine heat rejection. That figure is a design objective, not a claim of achieved operating performance.

Common misconceptions

PUE is not a complete sustainability score. It says nothing by itself about carbon intensity, water use, land use, or workload value.

Correctly measured PUE should not fall below 1.0.

See underwater cooling costs, Environmental Accountability, AI Infrastructure Statistics, and An Electron Is an Electron.