Data Center Clock: the AI and data centre boom, ticking in real time

01 · Guess first

Slough is a Berkshire town just west of Heathrow. What share of its electricity goes to data centres?

10%

02 · Why Slough?

Three-quarters of Britain's data centre power is drawn within an hour of Heathrow.

Data centres crave three things: fibre, power and proximity to customers. West London has all three, thanks to transatlantic cables, the City's trading firms and the Slough Trading Estate. The result is one of the densest clusters of computing anywhere in Europe.

77%of GB data centre electricity is used in London and the South East src

28%of Hillingdon's electricity, five times its 2020 level src

18%of Tower Hamlets' electricity (Docklands) src

586data centres listed in the UK, second only to the US src

Tap a dot to see what's there.

Existing hubs AI Growth Zones Major new projects · locations approximate, town level

03 · The map

Where the cloud lives, and where it's going next.

Every dot is a data centre that volunteers have mapped in OpenStreetMap or Wikidata: 4,004 sites worldwide, 248 of them in the UK src. Press Timeline to watch them pop up, or Planned to see what's been announced.

Tap a dot to see what's there.

Opening years are partly estimated: 3,839 of 4,004 sites have no recorded year and are placed on a modelled growth curve based on Synergy Research Group's hyperscale data centre counts src src (about 17.6% more a year, 2018–2024), assigned in a fixed order so the animation is the same every time. Estimated years are flagged in the data.

Coverage, honestly: the map shows 4,004 mapped sites (248 in the UK), not every data centre. Real totals are higher: Data Center Map lists 12,954 worldwide and 586 in the UK src, and Barbour ABI counted 477 in the UK src. Only 165 mapped sites (7 in the UK) carry a recorded year; in OpenStreetMap that start_date is sometimes the building's construction date rather than when it became a data centre. The other 3,839 appear in the timeline in an estimated year (see the small print above). Features within about 110 m of each other are merged into one site. Points are a building's first mapped corner or its tagged node.

Map data © OpenStreetMap contributors (ODbL), snapshot 21 September 2026, and Wikidata (CC0). Outlines: Natural Earth (public domain). Download the points (JSON).

04 · Zoom out

From one prompt to the whole planet.

Each step below is a real, sourced number. Watch how fast the scale runs away from you. Bars use a logarithmic scale, otherwise the first rows would be invisible.

“Homes” = typical UK home using 2,500 kWh a year src.

05 · Your AI habit

What does your chatbot habit actually cost?

Estimates disagree wildly, so we show three, from the most recent company disclosures to a widely shared 2024 estimate. That disagreement is itself the story.

Prompts per day 20

Per-prompt figures: Google median Gemini text prompt 0.24 Wh / 0.26 mL src; OpenAI CEO's ChatGPT average 0.34 Wh / 0.32 mL src; EPRI's 2024 estimate 2.9 Wh src. Cost uses the Ofgem price cap of 26.32p/kWh src; coffees use a £3.64 UK latte src; a glass is 200 ml src. The Washington Post's 2024 analysis put one 100-word GPT-4 email at 0.14 kWh and 519 mL of water src.

Perspective matters: even at 300 prompts a day, the newest per-prompt figures add up to a fraction of a UK home's electricity. The problem isn't your prompts. It's that billions of people, and ever more agents and video models, are prompting at once, and the buildings to serve them are being built at a scale never seen before.

06 · The queue

Britain's grid queue holds more data centres than Britain could ever power.

Of all the electricity demand waiting to connect to Britain's transmission grid, what share is data centres?

20%

07 · The money

Four companies, one year, roughly three-quarters of a trillion dollars.

Amazon, Alphabet, Microsoft and Meta guided to $720–745bn of capital spending for 2026, most of it on AI servers, buildings, power and cooling src. In 2024 the whole world invested about $0.5 trillion in data centres src.

131 billion

lattes. That's the midpoint of the 2026 guidance at the US average of $5.60 a cup src, or about 4,100 lattes every second, all year.

08 · Water

The thirst nobody sees.

Many data centres cool their servers by evaporating water. Google alone consumed about 31 billion litres across its data centres and offices in 2024 src, while its data centre electricity use grew 27% in a single year src.

Olympic pool = 2.5 million litres (50 m × 25 m × 2 m).

In glasses

155bn200 ml glasses: Google's 2024 water consumption src

71mpeople's recommended daily fluid intake (1.2 litres, UK advice) for a whole year src

2.6glasses for one 100-word AI email, by the 2024 Washington Post estimate src

1/770of a glass for a median Gemini prompt, by Google's own 2025 figure src

Two estimates about 2,000× apart: one is a company's own figure for a median short text prompt in 2025, the other an outside 2024 estimate for a 100-word email from an older model. Both are on the record; neither is the final word.

09 · Hotspots

Globally it's 1.5%. Locally it's a takeover.

10 · What's coming

The forecasts are all heading one way.

The IEA expects data centre electricity to grow about 15% a year to 2030, more than four times faster than everything else, with AI servers growing 30% a year src. In the US, Berkeley Lab projects 325–580 TWh by 2028, up to 12% of the nation's electricity src. In Britain, NESO forecasts just over 20 TWh by 2030 src.

11 · The upside

It's not all bad news. Here's the case for the sheds.

Data centres bring jobs, investment and tax, and the industry has a genuinely impressive efficiency record. Some of their waste heat is even starting to warm homes.

Between 2010 and 2018, the computing done in the world's data centres grew by 550%. How much did their energy use grow?

300%

43,500UK jobs supported by data centres, plus £4.7bn a year of GVA and £640m in tax src

£25bn+of UK data centre investment announced between July and October 2024 src

10,000+new West London homes to be heated with data centre waste heat, backed by £36m src

33×less energy per median Gemini prompt in May 2025 than a year earlier (Google's own figure) src

1.09Google's fleet PUE (1.0 = zero overhead) vs an industry average of 1.54 src

11.3 GWof clean power contracted by Amazon, Microsoft, Meta and Google in 2024 in the US alone src

Data centres were the biggest buyers in a record year for corporate clean energy: over 17 GW of the 68 GW of deals signed worldwide in 2024 src. No other sector came close: manufacturing was a distant second at 9 GW.

The fine print

Most jobs are in construction. CloudHQ's £1.9bn Didcot campus: 1,500 construction jobs, 100 permanent ones src.
The jobs, GVA and tax figures come from a report commissioned by techUK, the industry's trade body src.
Efficiency has stalled at the building level: the industry-average PUE has "virtually stood still" for six years src.
The 33× drop is Google's own figure, for a median text prompt, not an independent audit src.
A contract to buy clean power isn't the same as running on clean power every hour, which is why buyers are now chasing "24/7" matching and nuclear src.

12 · Live tracker

The build-out, as it's announced.

Every major UK and global data centre announcement, logged with its source. Updated regularly.

Now you know where the cloud lives.

Send this to the one friend who still thinks it's in the sky.

Sources & method

Every number on this page comes from the sources below. Derived figures (homes, pools, lattes, glasses, per-second tickers) are simple arithmetic on these, shown next to each one. Spotted an error? Email michael@builtbymichael.com.

The Data Center Clock.