The debate about how green cloud computing is rumbles on, but there is more and more evidence to support the view that cloud computing is, generally, more sustainable.
Jonathan Koomey is Consulting Professor at Stanford University and has researched and written extensively on electricity use by IT equipment. In a recent blog he gave four reasons why he thought cloud computing is (with few exceptions) significantly more energy efficient than using in-house data centres:
It’s cheaper for large cloud computing providers to make efficiency improvements because they can spread the costs over a larger server base and can afford to be more focused on addressing energy use.
With more users who are spread across different locations, computing loads are spread over the day, allowing for increased equipment utilisation. Cloud facilities for major vendors can be in the 30-40% utilisation range, compared with 5-15% for in-house data centres.
Cloud installations more often use virtualisation and other techniques to separate the software from the physical servers, which allows for the greater optimisation of servers.
Cloud computing sidesteps organisational issues, such as the problem of IT driving server purchases but facilities paying the electric bill. Cloud providers generally have one data centre budget and clear responsibilities assigned to one person.
Koomey concludes that there are still some issues to work out, but that the economic benefits are so large that we’ll see a whole lot more cloud computing in the coming years. As if to reinforce the point, Google is the latest company to offer an analysis of its own activities (see also Microsoft).
Google compared Gmail to the traditional enterprise email solutions it replaces and concluded that switching to Gmail can be almost 80 times more energy efficient than running in-house email. Google made the similar points that cloud-based services are typically housed in highly efficient data centres with higher server utilisation rates from purpose-built hardware and software. Something that small businesses just can’t do.
Google went on to say that it takes more energy to send a message in a bottle than it does to use Gmail for a year, if you include the energy used to make the bottle and the wine that was in it. Not a very good comparison, given that the wine and bottle were not made for sending messages. You could equally argue that by re-using the empty bottle, rather than it being recycled, sending the message is carbon negative and hence more efficient than using Gmail. Not quite as efficient, though!