Tom Raftery (of Greenmonk) writes:
…these servers will be almost entirely idle for eleven months of the year. The alternative is that the owners put the site on a cloud platform and dial up the resources associated with it, as and when needed. This is obviously a vastly more efficient option for the site owners. However, that doesnâ€™t mean that cloud computing itself is Green or efficient.
For cloud computing to be efficient, the individual servers need to be doing more work than they would be doing if not in a cloud infrastructure. The main cloud providers include Amazon, Google, IBM and more recently, Microsoft. As far as I know, none of these companies are providing utilisation data per unit, so it is not possible to know just how efficient cloud computing actually is.
I think you have to at least trust the business model of cloud computing. The whole point is that each core is utilised constantly – or as close to constantly as possible. The power sources for these datacentres can be sourced from renewable sources. The cores involved are going to be used for a wide variety of tasks therefore there is, in a global cloud, less cores created and powered overall (assuming not everyone has their demand surges at the same time.) The actual energy and materials required to create these cores are massive (compared to the size of the finished product)
The only caveat for large datacentres is that they require large amounts of air conditioning which as far as I can see, is not particularly green (though if it acted as a heat exchanger for apartments built around a datacentre then it would at least be greener and have a social consciousness element.
Where I consider Cloud Computing to be less than efficient and less than ‘green’ is in the spare capacity, in essence, how many cores are sitting waiting for the next surge of demand?