Now there's more data that could help answer that question.
Greenpeace has just released a report entitled How Clean is Your Cloud? In it, the environmental organisation highlights how the decisions all of us make as user/consumers are increasingly having an impact on technology's energy usage and CO2 emissions.
It also looks at and takes aim at some of the big names on the Internet, and the way that their technological innovation is not being matched by similar advances in energy efficiency.
The report notes that the growth of cloud s computing is driving growth in the numbers of datacentres but that: "Three of the largest IT companies building their business around the cloud – Amazon, Apple and Microsoft – are all rapidly expanding without adequate regard to source of electricity, and rely heavily on dirty energy to power their clouds."
On the other hand, Yahoo and Google garner praise for continuing "to lead the sector in prioritizing access to renewable energy in their cloud expansion, and both have become more active in supporting policies to drive greater renewable energy investment."
And perhaps the least surprising finding is the way that some companies continue to claim green credentials "despite a continued lack of transparency and very poor metrics for measuring performance or actual environmental impact."
So the big problem with technology companies is, as you might expect, a lack of visibility into energy usage, especially data that would reveal the numbers and size of their facilities. Vendors cite commercial confidentiality as a reason for hiding their energy sources.
Does it all matter in the great scheme of things? A 2010 report from Greenpeace calculated that: "The combined electricity demand of the internet/cloud (data centers and telecommunications network) globally in 2007 was approximately 623bn kWh. If the cloud were a country, it would have the fifth largest electricity demand in the world."
This is somewhat misleading as the Internet is clearly not the same thing as the cloud. In fact, cloud spending is, according to some figures I've seen, set to amount to between 2-10 percent of all enterprise IT expenditure. It's going to be more than that for consumers but the environmental organisation needs to be careful to avoid double-counting.
That said, Greenpeace proposes that that datacentre managers should report their CUE (carbon usage effectiveness), which was adopted by the Green Grid over a year ago, in addition to PUE. This means the datacentre would report not just the ratio of energy usage within the datacentre between computers and environmental equipment, but carbon usage too, so taking into account energy source efficiency.
Greenpeace's report also includes an interesting geographical analysis of both where major datacentres are located and their energy sources.
There's lots more in it: take a look...