Scotland's Digital Future: Report on the current landscape for Data Hosting and Data Centres in the Scottish Public Sector

This report sets out the findings of a review of the public sector data centre landscape. The landscape review was the first phase of the project to deliver the data hosting and data centre strategy published in April 2014. The findings in this report ref

Annex B - Power Usage Effectiveness ( PUE)

Energy use and Environmental impact

IT process (rack) power for Facility (ancillary/cooling power for non IT resource
servers lighting
storage equipment cooling
telco equipment heating
network equipment ventilation
etc. computer-room air conditioners
battery backup ( UPS)
power distributors

It is well recognised that data centres are large consumers of energy, the main areas are IT power and ancillary/cooling power.

The approaches to reduce these costs are expensive and for many organisations prohibitive.

Organisations can reduce the impact of their activities on the environment by taking advantage of the various deployment methods in this strategy.

  • cloud computing providers invest in large-scale data centres that offer organisations a greener alternative to that in which they can deliver themselves
  • organisations can share the cost of energy consumption through the co-location ( consolidation) of their servers and hosting them in a reduced number of facilities
  • another method of reducing the amount of energy consumed is through the virtualisation of servers where appropriate
PUE rating Level of Efficiency
>3 Very Inefficient
2.5 Inefficient
2 Average
1.5 Efficient
<1.2 Very Efficient

The only credible and widely accepted energy performance rating system for data centres used was introduced by The Green Grid who developed a standard to calculate how much power is being used by the IT equipment in a data centre in relationship to the power used to cool and run the data centre.

This recognised standard is known as the PUE (Power usage effectiveness) rating where the most efficient score is 1.

The rating is calculated by dividing the total data centre load by the IT load.


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