Green IT

A survey by Dell in 2006 found that more than half the power consumed at datacentra is not used for ICT services. Only Two fifths went to ICT resources, one third for cooling and the rest disappeared in such things as lighting and emergency power. For benchmark energy efficiency of a data center, the Power Usage Effectiveness (PUE)-formula is quite common.

According to figures from Dell, the average PUE in the pre-virtualization year 2006 was 2.5. Which means that for every Watt spent on ICT there is a loss of 1.5 watts. In the meantime most companies start virtualization to save power, space and cooling. But recent charts shows that there is still an upward trend in the total power consumption of computer centers. Not illogical as our dependence on ICT is also increased.

 

Specialized data centers 

Who has the virtualized the infrastructure and did nothing against the overhead could possibly have a PUE higher than in 2006. According to recent benchmarks the small and not very mature data centers have a PUE which lies between 3 and 3.5. While modern and specialized data centers, such as Google, a PUE of between 1.1 and 1.3.

These modern data centers use of course more innovative and efficient forms of cooling. Amsterdam uses for example the "city coldness" stored in the waters to cool offices and data centersl. And companies that do not have a deep water nearby store heat and cold in the ground. Given the fluctuations in the graph of Google, warmer quarters reqire more power but  it is certainly a clever way of saving. Unfortunately, the payback is that smaller data centers can not win back these investment easily.

Oversized computer rooms

Those companies that have an oversized computer room as result of virtualization should think about co-location their ICT resources to a modern Data center. Especially when the PUE exceeds the average value of 2006. Because ultimately this means that for every euro for electricity to ICT service at least one and a half euro is wasted. But most notable is the fact the real savings are not in virtualization so this argument used is half the story.