Global internet traffic surged by almost 40% between February and mid-April 2020 during the height of the Covid-19 containment measures, driven by growth in video streaming, video conferencing, online gaming, and social networking1. This growth comes on top of rising demand for digital services over the past decade: since 2010, the number of internet users worldwide has doubled while global internet traffic has grown 12-fold, or around 30% per year.367

Demand for data and digital services is expected to continue its exponential growth over the coming years, with global internet traffic expected to double by 2022 to 4.2 zettabytes per year (4.2 trillion gigabytes). The number of mobile internet users is projected to increase from 3.8 billion in 2019 to 5 billion by 2025, while the number of Internet of Things (IoT) connections is expected to double from 12 billion to 25 billion.8 These trends are driving exponential growth in demand for data centre and network services.

Most of the world’s Internet Protocol (IP) traffic goes through data centres. Greater connectivity is therefore propelling demand for data centre services and energy use (mostly electricity), with multiplying effects: for every bit of data that travels the network from data centres to end users, another five bits of data are transmitted within and among data centres.4

Global data centre electricity demand in 2019 was around 200 TWh, or around 0.8% of global final electricity demand.2

If current trends in the efficiency of hardware and data centre infrastructure can be maintained, global data centre energy demand can remain nearly flat through 2022, despite a 60% increase in service demand.2

Global data centre energy demand by region, 2010-2022

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Strong growth in demand for data centre services continues to be offset by ongoing efficiency improvements for servers, storage devices, network switches and data centre infrastructure, as well as a shift to much greater shares of cloud and hyperscale data centres.

Hyperscale data centres are very efficient large-scale cloud data centres that run at high capacity, owing in part to virtualisation software that enables data centre operators to deliver greater work output with fewer servers.

The shift away from small, inefficient data centres towards much larger cloud and hyperscale data centres is evident in the shrinking share of data centre infrastructure in total energy demand, given the very low power usage effectiveness (PUE) of large data centres. PUE is a measure of how efficiently a data centre uses energy; the very best hyperscale data centres can have PUE values of around 1.1 (meaning 0.1 kWh used for cooling/power provision for every 1 kWh used for IT equipment).

Data transmission network technologies are also rapidly becoming more efficient: fixed-line network energy intensity has halved every two years since 2000 in developed countries,9 and mobile-access network energy efficiency has improved by 10‑30% annually in recent years.1011 For example, Sprint has reduced its network energy intensity by more than 80% between 2014 and 2018, keeping total network energy consumption flat.

Data networks consumed around 250 TWh in 2019, or about 1% of global electricity use, with mobile networks accounting for two-thirds. Based on current efficiency improvement trends, electricity consumption is projected to rise to around 270 TWh in 2022.

Several trends are shaping the future of data network electricity use. Global IP traffic doubled between 2016 and 2019, and is projected to double again by 2022.6 The nature of data transmission is changing rapidly, with traffic from wireless and mobile devices expected to make up more than 70% of total IP traffic by 2022, up from around 50% in 2019.5

This shift towards greater use of mobile networks may also have significant implications for the energy use of data transmission networks, given the considerably higher electricity intensities (kWh/GB) of mobile networks compared with fixed-line networks at current traffic rates.

Mobile networks are rapidly shifting away from older 2G and 3G technology towards more efficient 4G and 5G. By 2022, 4G and 5G networks are expected to carry a combined 83% of mobile traffic, compared with less than 1% for 2G.5

4G networks are roughly five times more energy efficient than 3G and 50 times more efficient than 2G. The overall energy and emission impacts of 5G are still uncertain. While a 5G antenna currently consumes around three times more electricity than a 4G antenna, power-saving features such as sleep mode could narrow the gap to 25% by 2022.1213 Network infrastructure providers and operators are projecting that 5G could be up to 10 to 20 times more energy-efficient than 4G by 2025-30.

Demand for data centre and network services will continue to grow strongly, driven in particular by rapidly growing demand from streaming video and gaming. Between 2019 and 2022, traffic from internet video is projected to more than double to 2.9 ZB, while online gaming is projected to quadruple to 180 EB.6 Together, these streaming services are projected to account for 87% of consumer internet traffic in 2022.

Additionally, emerging digital technologies such as machine learning, blockchain, 5G, and virtual reality are also poised to raise demand for data services.

For example, electricity used by Bitcoin miners – one prominent example of emerging blockchain IT infrastructure – likely consumed 50-70 TWh in 2019, or 0.2‑0.3% of global electricity use.1514 However, as blockchain applications become more widespread, understanding and managing their energy-use implications may become increasingly important for energy analysts and policy makers.