Greenpeace activists in Israel send Microsoft an error message for its use of coal.

Microsoft has turned up at the Rio+20 Earth Summit in Brazil, unveiling a new website featuring a calculator that it says shows how much energy would be saved if more businesses moved their data to the cloud.

Now, there’s some truth to that idea.

The cloud could be a great tool to reduce the amount of carbon pollution from the IT sector if the data centres that form the backbone of the cloud are powered by clean energy. But if those data centres are powered by coal plants, then the growth of the cloud would lock in decades of carbon pollution. 

That’s why we found one passage particularly interesting that was in the report Microsoft supported and used as the basis of its new cloud calculator tool:

Finally, we also show that energy mix is more influential than power use effectiveness (PUE). This is intriguing because, at present, the ICT sector is investing a lot of resources into improving the overall efficiency of data centres and data centre technology (measured as its power use effectiveness). Yet, our research shows where a Cloud data centre is located is more important in CO2 terms than the overall efficiency of the data centre - a cleaner energy source will more readily deliver higher carbon savings than investing in efficiency. (page 20)

Hallelujah! That’s a fantastic statement to read in a report supported by Microsoft.

Finally, Microsoft is moving away from all the hype about how green the cloud is because of its efficiency –Microsoft actually understands that you can’t have a green cloud powered by coal and that the real path to being green is powering the data centre with clean energy… right?

Unfortunately, the people in charge of making decisions about where Microsoft’s data centres are built don’t seem to have read the report the company helped to write. Microsoft’s latest data centres in Virginia and Wyoming in the United States will rely heavily on coal, according to US EPA data for those states electricity mixes.

But wait, Microsoft just adopted an internal carbon tax and committed to being “carbon neutral,” so we can bank on Microsoft’s cloud being green, right?

Again, unfortunately not; so far Microsoft’s way of being “carbon neutral” allows it to keep building data centres that rely on coal while claiming to be carbon neutral by buying renewable energy credits (RECs) and carbon offsets. RECs are similar to carbon offsets in that they allow companies to pay others who actually produce renewable energy.

In other words, Microsoft’s use of RECs means that no less coal is burned and no more renewable energy is produced to power the Microsoft cloud.

Microsoft should listen to its own experts and adopt a siting policy, as Facebook has, that prioritises clean energy when it builds new data centres.