The UK’s datacentres used 1.8% of all Great Britain’s grid electricity in 2024. That proportion had increased from 1.2% in 2020. That electricity draw was heavily concentrated, with Slough and Hillingdon together drawing nearly three times that of the North, Midlands, Scotland, the South West and Wales combined.
Meanwhile, as computing got more intensive alongside the rise of artificial intelligence (AI), datacentre electricity consumption increased by 41% while the datacentre count rose by only 8%. That means each datacentre counted became 31% hungrier.
That’s all according to data published by the Department for Energy Security and Net Zero (DESNZ) and analysed here by Computer Weekly. Datacentres are one of the few sectors that still add demand to the grid. Total electricity demand in Great Britain is essentially flat. DESNZ’s Digest of UK energy statistics records 2025 demand of 323TWh (terawatt-hours), which was below pre-pandemic 2019 levels.
Renewables generated a record 153TWh in 2025, a 52.1% share of all generation. Fossil fuels, meanwhile, generated 94.9TWh in the first full year without coal. A datacentre estate that draws 4.46TWh consumes about a fifth of everything Britain’s solar panels produced in 2025. Meanwhile, industrial consumption fell for a fourth consecutive year to 76.7TWh, its lowest since 1983. Domestic consumption sat at 96.2TWh and commercial consumption at 67.9TWh.
In this article, we look at datacentre electricity demand, how it is growing, where it has grown and how its growth has become more concentrated in particular regions. We also look at how AI compute has seen the power draw per site become denser.
Where the power goes
DESNZ splits its estimates by area, and that distribution is a big part of the story. Nearly all recent growth concentrates in west London and the M4 corridor, while most of the country is going in the other direction.
Slough’s datacentres consumed 1.29TWh in 2024 – 65.2% of the borough’s grid electricity, up from 44.4% in 2020. Hillingdon’s datacentre share of the borough’s grid electricity climbed from 7.4% to 28.1% over the same period, with Tower Hamlets, home to the Docklands colocation hub, drawing 18.2% of the borough’s grid electricity. Between them, datacentres in Slough and Hillingdon drew 1.83TWh – nearly three times as much as those in the North, Midlands, Scotland, South West and Wales combined, at 0.68TWh.
The growth is just as lopsided. Hillingdon’s datacentre consumption rose by 407% between 2020 and 2024, Outer London by 85% and the South East by 57%, while the South West and Wales rose by 107% from a small base. The direction reverses elsewhere. The North fell by 20%, the Midlands 24%, Scotland 11%, and the rest of the South East – the commuter belt beyond the M4’s core – by 22%, while Hampshire rose by 23% and Greater Manchester was broadly flat. The much-discussed regional build-out is not visible in the electricity data.
The geography results from where fibre is most dense and interconnection points sit, which is why the Slough-Hillingdon axis and London’s Docklands have anchored the UK’s colocation industry for two decades.
The much-discussed regional build-out is not visible in this electricity data, but it dates from 2020-2024, so perhaps redressing that imbalance explains more recent initiatives such as AI growth zones.
The divergence between sites and power reveals the roll-out of newer, denser and more power-hungry AI compute. DESNZ counted 239 operational datacentres in 2024, up from 221 in 2020. That was a rise of only 8%, but it is set against a 41% rise in electricity consumption.
The average metered site drew about 14.3GWh in 2020 and 18.7GWh in 2024, a 31% increase. New datacentres are more numerous but lots hungrier on a per-site basis. That’s the signature of hyperscale and AI-era builds that pack more compute and more cooling into each data hall. A single modern AI aisle can draw more power than an entire older colocation facility, which is why count and consumption diverge, and a nearly flat site count can hide a steep rise in consumption.
DESNZ’s count of 239 deserves scrutiny. It built its dataset by matching electricity meters to a compiled register of datacentres, and counted each campus building separately. Computer Weekly’s analysis of the government’s Energy Performance Certificate registers found roughly 90 to 110 datacentre sites across England, Wales and Scotland after manual verification. That is less than half the DESNZ figure, but likely maps to the fact that many datacentres counted by Computer Weekly comprise multiple metered buildings.
The methodology behind the data
The DESNZ estimate matches meter-level electricity consumption – the same data used for its subnational electricity statistics – to a list of datacentres, and counts a facility as operational only if at least one meter matched. It covers colocation, managed hosting and hyperscale datacentres, and explicitly excludes enterprise facilities owned and run for an organisation’s own IT. That means the 4.46TWh and 1.8% figures are a floor that leaves out private enterprise datacentres.
DESNZ notes that the estimates carry uncertainty. Some regions are combined, and a facility only counts as operational if a meter can be matched to it. The percentage-of-grid figures are measured against each area’s own electricity consumption, which is why they spike where the local denominator is small – Slough’s datacentres draw nearly two-thirds of a borough that has relatively little else that draws power.
Britain’s electricity use curve is flat to falling. Demand is below 2019 levels, and industrial consumption is at its lowest since 1983. Meanwhile, renewables push to a record share of generation. DESNZ’s 4.46TWh equates to about 4.6% of domestic electricity use (96.2TWh in 2025). So, a sector that adds 41% in four years – and concentrates it in a single corridor – is the exception to an overall decline.
That concentration of demand evident in the DESNZ data runs against the geography of the current build-out. Computer Weekly’s tracking of committed pipeline counts more than 14GW of planned capacity, with the largest schemes heading for the North East and Scotland. That’s probably a good thing because the grid access that London and the M4 corridor lack is exactly what the regions can offer.
