The world is becoming increasingly dependent on information and communications technology. The ‘backbone’ of the computing and networking infrastructure underlying these increasingly critical digital services are data centres, which house the computing, storage and networking used to process, store and communicate data. Data centres currently consume about 1% of all electricity, a level that has not increased considerably in the last decade despite exponential growth in the number of internet users and connections during that time. This discrepancy is attributed to technology developments, specifically improvements in hardware efficiency, advancements in the management of cooling and heat dissipation, and more efficient utilisation of computing instances. Projections of how much electricity data centres will use as they continue to expand and evolve interest policymakers, energy network operators, data centre operators and environmentalists.