My favorite part of highways in the American midwest are the wind turbines. Not so much the massive wind turbines on the horizon, begging for a contemporary Don Quixote to come at them, but the bits and pieces of wind turbines—single fan blades and bits of foundation—that pass by on longhaul trucks. They’re like an exploded diagram on wheels, a useful reminder of the sheer scale and complexity entailed in building energy systems.
Data-center operations managers love to talk about energy systems—or, more specifically, efficiency in theiruse of energy systems. The fact that companies increasingly foreground this sustainability information when engaging with journalists demonstrates a growing public interest in The Cloud’s environmental impact. But really articulating and measuring that impact is difficult. It basically requires taking apart the constituent parts of the data center itself.
Starting around 2006, power-usage effectiveness (PUE) has been the metric of choice for the data-center industry. PUE is a ratio created by the Green Grid Association, a consortia of IT industry professionals dedicated to “accountable, effective, resource-efficient, end-to-end ICT ecosystems.” It’s a fairly simple measurement of a data center’s total power usage to the power usage of its actual IT equipment. It’s more a metric of efficiency than of environmental impact.