PUE (Power Usage Effectiveness

PUE (Power Usage Effectiveness) is one of the key indicators determining the energy efficiency of server rooms and data centers. In the current conditions of IT infrastructure growth, the issue of energy saving becomes especially important, and PUE serves as the main standard for evaluating energy efficiency in information technologies.

What is PUE?

PUE is the ratio of total data center power consumption to the power consumption of the IT equipment itself. Simply put, it demonstrates how much electricity is used to maintain the infrastructure (cooling, lighting, backup power systems and other services) compared to the energy consumption of servers, storage and networking equipment.

The PUE concept was proposed in the early 2000s by The Green Grid, an association of data center and energy efficiency experts. This index has become a standard widely used to evaluate the energy efficiency of server rooms and data centers around the world. There is a clear downward trend in PUE values, indicating an increase in energy optimization measures.

PUE calculation formula

The formula for calculating Power Usage Effectiveness is as follows:

PUE = Total Data Center Power Usage / IT Equipment Power Usage

PUE values are always greater than or equal to 1. The closer the value is to one, the higher the energy efficiency.

PUE allows calculating another important parameter - data center infrastructure efficiency (DCIE). It is calculated using the following formula:

DCIE = 1 / PUE = IT equipment energy consumption / Total data center energy consumption x 100%

Ideal energy efficiency values

• PUE = 1.0 - completely ideal case where all electricity is used directly on IT equipment with no infrastructure losses (practically unattainable).
• PUE in the range of 1.1-1.4 - considered excellent for modern data centers.
• PUE above 1.5 - signals significant energy losses and the need for optimization.

Limitations of PUE

Despite its widespread acceptance, PUE has a number of limitations:

• Does not account for the quality of energy resources and their recoverability.
• Does not reflect the efficiency of IT equipment utilization within the server.
• Can be misleading if data is not collected or interpreted correctly.

Ways to reduce PUE

The following recommendations are used to improve energy efficiency and reduce PUE:

• Cooling system optimization: use of cold and hot corridors, implementation of free cooling (free cooling).
• Energy-efficient equipment: switch to energy-efficient servers and IT equipment.
• Load management: balancing and virtualization of server resources to increase their utilization.
• Utilization of renewable energy sources in infrastructure.
• Monitoring and automation: continuous monitoring of energy consumption using DCIM management systems.

PUE is an indispensable tool for assessing and improving the energy efficiency of server rooms and digital infrastructures, reflecting the balance between the cost of maintaining infrastructure and operating IT equipment. Continuous monitoring and optimization of this indicator helps to reduce energy consumption and increase the sustainability of data centers.