Data Center Power Foundations

Glossary

800-volt direct current distribution

A data center power design, promoted by NVIDIA from 2025, in which power is converted to 800 volts direct current near the facility edge and carried to the racks, reducing current, copper and conversion steps.

Behind the meter

Generation that serves a load directly on the customer's side of the utility meter, without the power passing through the public grid; contrasted with front-of-the-meter supply delivered over utility wires.

Concurrent maintainability

The Uptime Institute's Tier III standard: any single component or distribution path can be removed for planned maintenance without interrupting the computing load.

Medium voltage

In American practice, alternating current distribution at roughly a few thousand to a few tens of thousands of volts, used to carry power around a campus before it is stepped down for equipment.

Power purchase agreement (PPA)

A long-term contract to buy electricity, or its financial value, from a specific generator at an agreed price. It may be physical, delivering power, or virtual, settling financially against market prices.

Power usage effectiveness (PUE)

The ratio of a facility's total energy use to the energy used by its computing equipment, defined by The Green Grid. A value of 1.0 would mean zero overhead for cooling, conversion and lighting.

Terawatt-hour

A unit of electrical energy equal to one billion kilowatt-hours. National and global data center consumption is usually reported in terawatt-hours per year.

Uninterruptible power supply (UPS)

Equipment that carries the computing load on stored energy, usually batteries, during the seconds between a utility failure and the start of backup generators, and conditions incoming power.