The IT industry uses a lot of power. It’s arguable that its entire history is determined at a fundamental level by the properties of electricity. Processors have gone multi-core because single cores have cooling problems at higher speeds, some peripherals such as display adapters have their own cooling units for the same reason, there’s a massive global shift to virtualised infrastructure for power and efficiency reasons, and datacentres have been redesigned to be as efficient as possible.

One of the biggest wakeup calls was published in 2007: a study from Lawrence Berkeley National Laboratory that estimated that the US spent nearly $3 billion in 2005 keeping its datacentres on and cooled and that the world in total spent $7 billion. But since then, datacentres, by far the hungriest consumers of power, have gone virtual.