This document specifies power usage effectiveness (PUE) as a key performance indicator (KPI) to quantify the efficient use of energy.

This document:

1. defines the PUE of a data centre;
2. introduces PUE measurement categories;
3. describes the relationship of this KPI to a data centre’s infrastructure, information technology equipment and information technology operations;
4. defines the measurement, the calculation and the reporting of the parameter;
5. provides information on the correct interpretation of the PUE.

PUE derivatives are described in Clause 9.