Although sometimes portrayed as a big computer in the sky, the reality of cloud computing is far more mundane. Clouds run on physical hardware, located in data centres, connected to one another and to their customers via high speed networks. All of that hardware must be powered and cooled, and all of those offices must be lit. Whilst many data centre operators continue to make welcome strides toward increasing the efficiency of their buildings, machines and processes, these advances remain a drop in the ocean next to the environmental implications of choices made about power source. With access to good information, might it be possible for users of the cloud to make choices that save themselves money, whilst at the same time saving (a bit of) the planet? Greenpeace has consistently drawn attention to the importance of energy choices in evaluating the environmental credentials of data centres, with 2011′s How Dirty Is Your Data? report continuing to polarise arguments after more than a year. The most efficient modern data centres deploy an impressive arsenal of tricks to save energy (and therefore money), and to burnish their green credentials. They use the most efficient modern processors, heat offices with waste server […]