Called the carbon-free energy percentage (CFE%), the number reflects the average mix of carbon-free and fossil-fuel energy that is used to power Google’s data centers in each region. The higher the percentage, the more carbon-free power was used in the mix; in other words, a high CFE% is indicative of a “greener” region.
Link: How clean is cloud computing? New data reveals how green Google’s data centers really are
via http://www.zdnet.com
