I recently read a post by Jon Koomey, Consulting Professor at Stanford, at www.climateprogress.org, called “4 reasons why cloud computing is efficient”. He argues (along with some other folks) that cloud computing – by which he apparently means almost entirely public clouds – is much more beneficial for reducing computing’s carbon emissions than the real-world alternatives. As a computer industry analyst greatly concerned by carbon emissions, I'd like to agree with Jon; I really would. However, I feel that his analysis omits several factors of great importance that lead to a different conclusion.
The study he cites compares the public cloud -- not a private or hybrid cloud -- to "the equivalent". It is clear from context that it is talking about a "scale-out" solution of hundreds and thousands of small servers, each with a few processors. This is, indeed, typical of most public clouds, and other studies have shown that in isolation, these servers do indeed have a utilization rate of perhaps 10-20%. However, the scale-up hundreds-of-processors servers that are a clear alternative, and which are typically not used in public clouds (but are often used in private clouds), have a far better record. The most recent mainframe implementations, which support up to a thousand "virtual machines", achieve utilization rates of better than 90% -- a three times better carbon efficiency than the public cloud, right up front.
The second factor Jon omits is the location of the public cloud. According to Carol Baroudi, author of "Green IT For Dummies", only one public cloud site that she studied is located in an area that has a strong record of electricity that is carbon-emission-light (Oregon). The others are in areas where the energy is "cheaper" because of fossil fuel use. That may change; but you don't move a public cloud data center easily, because the petabytes of data stored there to deliver high performance to nearby customers doesn't move easily, even over short distances. Corporate data centers are more movable, because the data storage sizes are smaller and they have extensive experience with "consolidation". While until recently most organizations were not conscious of the carbon-emission effects of their location, it appears that companies like IBM are indeed more conscious of this concern than most public cloud providers.
The third factor that Jon omits is what I call "flight to the dirty". High up-front costs of more efficient scale-up servers leads unconsciously to use of less energy-efficient scale-out servers. Controls over access to public and private clouds and data centers, and visibility of their costs, moves consumer and local computing onto PCs and smartphones. Apparent cheapness of labor and office space in developing nations leads companies to rapidly implement data centers and computing there using existing energy-inefficient and carbon-wasting electrical supplies. All of these "carbon inefficiencies" are not captured in typical analyses.
Personally, I come to three different conclusions:
1. The most carbon-efficient computing providers use scale-up computing and integrated energy management, and so far most if not all of those are private clouds.
2. The IT shops that are most effective at improving carbon efficiency in computing monitor energy efficiency and carbon emissions use not only inside but outside the data center, and those inevitably are not public clouds.
3. Public clouds, up to now, appear to be "throwing good money after bad" in investing in locations that will be slower to provide carbon-emission-light electricity -- so that public clouds may indeed slow the movement towards more carbon-efficient IT.
A better way of moving computing as a whole towards carbon-emission reductions is by embedding carbon monitoring and costing throughout the financials and computers of companies. Already, a few visionary companies are doing just that. Public cloud companies should get on this bandwagon, by making their share of carbon emissions transparent to these companies (and by doing such monitoring and costing themselves). This should lead both parties to the conclusion that they should either relocate their data centers or develop their own solar/wind energy sources, that they should move towards scale-up servers and integrated energy management, and that they should not move to less costly countries without achieving energy efficiency and carbon-emission reduction for their sites up front.