Power Usage Effectiveness (PUE)

Calculate energy efficiency in the data centre with Power Usage Effectiveness

Power Usage Effectiveness (PUE) is a fundamental indicator for evaluating the energy efficiency of data centres. It has been the industry standard since 2006. The PUE value is calculated by dividing the total energy consumption of a data centre by the energy consumption of the IT infrastructure.

Calculating the PUE value

The Power Usage Effectiveness is calculated using the following formula:

PUE = total energy consumption / energy consumption of IT equipment

The ideal value is 1.0, which means that all the energy is used exclusively for the IT infrastructure. In practice, however, this value is not achievable because additional energy is needed for cooling, lighting and other functions.

What does the Power Usage Effectiveness value indicate?

In 2023, the average PUE value in Germany was 1.8. This shows that only about 56 per cent of the energy actually benefits the IT infrastructure. The current industry standard is 1.5, while highly efficient data centres. Google’s data centre in St. Ghislain, Belgium, achieves a value of 1.09. This would then be calculated as follows:

PUE = 109 MW / 100 MW = 1.09

The closer the PUE value is to 1.0, the more energy efficient a data centre is. A value above 2.0, on the other hand, is considered inefficient.

PUE measurement categories

There are four standardised categories for precisely determining power usage effectiveness. The four categories indicate how precisely energy consumption is measured.

  • Category 0: Total and IT energy consumption are roughly estimated in category 0 to provide an initial impression.
  • Category 1: By measuring energy consumption at the building level, fundamental analyses are possible.
  • Category 2: Cooling or power distribution can be measured in more detail to enable further optimisation.
  • Category 3: Components such as individual servers or air conditioning units can be measured separately to achieve maximum accuracy.

What does the PUE value tell us?

In 2023, the average PUE value in Germany was 1.8. This shows that only about 44 percent of the energy actually benefits the IT infrastructure. The current industry standard is 1.5, while highly efficient data centres, such as Google’s, come close to 1.0.

The closer the PUE is to 1.0, the more energy efficient the data centre. Anything over 2.0 is considered inefficient.

Factors that influence PUE

  • Negative factors: Cooling and climatic conditions can have a negative impact on the value.

Discover our PDU selection

How a PDU can improve the value

Efficient power distribution units (PDUs) play a key role in optimising the PUE. Discover our metered PDUs, which can help you to do just that. They monitor important parameters such as current, power consumption, voltage and power factor. Our PDUs provide a detailed record of the energy consumption of IT equipment, enabling targeted improvements to the PUE.

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