Amid headlines about the UK’s drought, Europe’s wildfires and impossible global temperatures, it was 28C when I arrived in Slough last Monday. I was there to look around Slough Trading Estate, a place that might once have conjured up images of the TV comedy The Office, many of whose laughs came at the expense of this overgrown patch of suburbia, 20-odd miles west of London.
But these days, this area of town – an incongruous mixture of old-school businesses such as Mr Clutch and Angling Direct, and vast, metal-clad leviathans that look like something pulled from JG Ballard – has become a byword for the constant expansion of datacentres, those hulking symbols of the vast computing power that big tech now requires, not least because of the ever-more complex workings of artificial intelligence.
In many people’s minds, datacentres are also a byword for the two totemic issues of yet another searing summer: heat and water. Across the world, the huge amounts of electricity they demand, mostly generated using fossil fuels, indelibly connects them to the climate emergency. The constant machinations of their crammed-in servers require cooling processes that also use vast amounts of water. So it is that the 21st century’s dominant means of communication intensifies our era’s most terrifying threats.
The first building I loitered around was a datacentre owned by the California-based company Equinix. There were 100 or so cars in its “visitor” and “staff” spaces, no corporate branding to be seen – and, up close, the constant sound of a low industrial whirr. On the other side of the street, poetically enough, was a set of offices occupied by Thames Water, a few of whose employees were taking a break outside. I pointed across the road: did they know what the building contained?
“There’s loads of AI bits in there,” said a twentysomething woman called Louise. “I saw something about it on Instagram: all the water they use.” She rolled her eyes. “It’s ridiculous. Loads and loads of water because of all the AI.” On her phone, she found one of the posts she had seen. “Slough is quietly running Britain’s AI boom but there’s a problem,” it said. “When a heatwave hits, the machines get thirsty too. Cooling systems work overtime in hot weather, spiking demand for power and water.”
Someone suggested I make the five-minute journey to nearby Britwell, a housing estate built for bombed-out Londoners after the second world war. The first person I encountered was a mum from the area called Sheryl. “You notice the noise at night: like a whirring, buzzing sound,” she said. “And since we’ve had all these [new] ones up here, there seems to be more heat round here.”
Early research, including a recent preprint of a paper authored by researchers at Cambridge University earlier this year, does suggest that datacentres can have a “heat island” effect, pushing up temperatures in their immediate vicinity by an average of 2C, and as much as 9C. Last month, the trading estate’s corporate owners said they had “not seen conclusive evidence demonstrating that datacentre operations on Slough Trading Estate are causing increases in local temperatures”.
Slough has the densest cluster of datacentres in western Europe: as many as 40, with more to come. What has happened here is bound up with the trading estate’s recent history as a partly deregulated “simplified planning zone”, the town’s proximity to London (the faster that digital financial transactions can happen, the better), and the apparently flukish fact that Slough sits atop the cables that connect Britain to the US and Ireland. The datacentres the town hosts are owned and maintained by companies that are far from being household names – Equinix, Digital Realty, Iron Mountain – but serve famous customers including Amazon, Google, Oracle and Microsoft.
Fierce arguments about datacentres are a big part of the discourse surrounding the upcoming US midterm elections, with Donald Trump taking a predictable position: “You have to convince your community how great these things [are] … You can’t fight it.” But actually, you can. Resistance is now pouring into the US political mainstream: midway through last month, New York became the first state to impose a one-year pause on new “hyperscale” datacentres, and, as litigation is fought out across the country, there is mounting pressure for other parts of the US to follow suit. The leftist insurgent Abdul El-Sayed, who last week won a Democratic Senate primary in Michigan, has crisply captured the mood: “People really effing hate datacentres,” he says. Even the Republican governor of Texas has called for a ban on their development in rural areas, and last week ordered that new centres won’t join the state’s power grid until regulators have reviewed their use of water and energy.
Increasing numbers of US facilities have their own dedicated gas turbines; in the UK, high-ups at the energy regulator Ofgem say that 100 planned centres here aim to do the same. US sites are putting added pressure on existing power grids that also use coal and oil, and backup generators powered by diesel are a standard industry feature. Green datacentres are attracting growing interest, but many insiders insist that renewables simply don’t cut it: “Our datacentres have to run 100% of the time so we can’t even consider using [renewables] as a primary source,” one industry kingpin told the Financial Times last year.
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With good reason, not many people are minded to listen to private water companies. But only a fortnight ago, Water UK, the organisation that represents firms in the four nations, said that the government’s existing water forecasts were “fatally flawed” and “explicitly exclude” datacentres, which can use up to 5m gallons a day, equivalent to the consumption of up to 50,000 people. What that omission says about our readiness for more datacentres – and what will happen during inevitable future droughts – is an interesting question. Would the public be expected to stoically limit their use of water while datacentres carried on guzzling it?
All sorts of tensions could soon explode. For all Andy Burnham’s talk of local decision-making, Whitehall’s official aim is still to triple the UK’s number of datacentres by 2030, which could be aided by the fact that they are now classed as critical national infrastructure. In December, a report by the London assembly revealed that datacentres’ electricity requirements had led to stalled housebuilding in the capital; last week brought news of the returned housing secretary, Angela Rayner, approving a redevelopment of the old Truman Brewery site in east London that had been called in by her predecessor, Steve Reed. It will include a datacentre handling transactions in the City, offices and 44 homes, in contrast to plans supported by the local council centred on 350 new dwellings. Whatever that represents, it doesn’t sound like what the new PM calls “good growth in every postcode”. There may, in fact, be a stark choice lurking in such stories that politicians will soon have to face: homes or servers?
On my way out of Britwell, I had a chat with a woman called Jodie, on her way home from Lidl. “My brother said he saw something on TikTok that said if there was a war, Slough would be a target because of the datacentres,” she said. I grimly laughed: “Come friendly bombs and fall on Slough”, and all that? “Let’s hope not,” she said. In the middle distance, the increasingly gigantic datacentres whirred on, and I thought of a few lines from another of John Betjeman’s poems: “And over all the land, instead of trees / Clean poles and wire will whisper in the breeze / We’ll keep one ancient village just to show / What England once was when the times were slow.”
