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Eco-Design Web Development

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Notion 24

PUE rating and efficient web applications.

Target skills

Learn what the PUE (power usage effectiveness) of data centres is.

Data centres' power consumption efficiency can be measured with the help of the units called PUE (Power Usage Effectiveness).

How to determine PUE and its ideal value

PUE is calculated by dividing the total amount of energy used by a data centre by the power used for operating its IT equipment.
Basically, it represents the proportion of energy used by computers compared to the energy used by other systems such as cooling and lighting.

Another criterion to choose your web host is their low PUE. An ideal PUE is 1.0, which is equal to 100 % efficiency. That means that all the consumed power is used by IT equipment and there are no power distribution losses. Though perfect efficiency can hardly be achieved, there are companies getting very close. According to Uptime Institute survey, the average PUE for data centres in 2021 was 1.57. High efficiency data centres such as those run by Google have a PUE as high as 1.11.

There is a software that helps to monitor, manage and measure energy usage across all assets in the data centre. It is called Data centre Infrastructure Management (DCIM) software.

Data Structure Efficiency (DCiE) is correlative to PUE and represents the energy efficiency of a data centre in percentages. The formula to calculate it is the following: DiCE=(1/PUE) x 100. Based on this formula the average PUE mentioned above is 63%.

Here is the table that illustrates efficiency levels based on PUE and DCiE: