Data centre power consumption
The key figures on how much electricity data centres use, in the UK and worldwide, each quoted from its original source. Sources measure different things (Great Britain or the UK, connected capacity or demand), so we don't combine them.
Worldwide
- The International Energy Agency (IEA) puts data centres at around 1.5% of the world's electricity in 2024, or 415 TWh, having grown by around 12% a year since 2017. The US accounted for 45%, China 25% and Europe 15%.
- In its 2026 update, the IEA says data centre electricity use grew by 17% in 2025, with AI-focused data centres up 50%, and expects it to roughly double from 485 TWh in 2025 to 950 TWh in 2030, around 3% of global demand.
The UK
- The House of Commons Library says data centres consume around 2.5% of the UK's electricity, a figure expected to rise four-fold by 2030. It puts UK data centre capacity at about 1.6 GW in 2024, with preliminary analysis for the government suggesting 3.3 GW to 6.3 GW by 2030.
- The National Energy System Operator (NESO) estimates data centre demand in Great Britain at 7.6 TWh, from 2.4 GW of connected facilities. NESO's capacity figure is higher than the Commons Library's; they come from different sources and definitions.
| Pathway | 2035 | 2050 |
|---|---|---|
| Holistic Transition | 37 TWh | 65 TWh |
| Electric Engagement | 41 TWh | 71 TWh |
| Hydrogen Evolution | 30 TWh | 51 TWh |
| Falling Behind | 20 TWh | 30 TWh |
Source: NESO, Future Energy Scenarios 2025, table 16.
Grid connections
- In March 2026 the government said the transmission demand queue grew by 460% in the six months to June 2025, with waits of up to 15 years, and that strategically important projects, including AI Growth Zones, would move to the front.
- In July 2026 Ofgem said demand connection applications had risen from 41 GW to 125 GW in under a year, with data centre projects accounting for "at least 80GWs". It proposed a data centre commitment fee of £237,500 to £712,500 per megawatt to discourage speculative applications; the consultation closed on 16 September 2026.
- The North East AI Growth Zone is set to increase its energy capacity to 1.1 GW over six years, according to the government's announcement.
Efficiency: PUE
Power usage effectiveness (PUE), defined in the international standard ISO/IEC 30134-2 (2026 edition), compares the total energy a data centre uses with the energy that reaches its IT equipment. A PUE of 1.0 would mean every unit of power goes to the IT; anything above that is cooling, power conversion and other overheads.
The Uptime Institute's 2026 global survey found an industry-wide average PUE of 1.52, or 1.36 when weighted by capacity, because large new facilities "routinely report PUEs at 1.3 or lower".
How big are individual sites? See the biggest UK data centres by capacity, or how many there are.