Research firm SemiAnalysis forecasts that about 50 gigawatts (GW) of new data centre capacity will be built in 2027. It says the buildout is accelerating. The figure comes from a report published on 19 October by Jeremie Eliahou Ontiveros, Reyk Knuhtsen and Dylan Patel, titled “Datacenters 2027: The Year of Acceleration, +50GW in a Single Year“.
All the numbers in the report are SemiAnalysis’s own forecasts and estimates, drawn from its paid Datacenter Industry Model. None has been confirmed by a third party. Most of the report is for paying subscribers. This article is based only on the free preview.
“To be fair, +50GW is essentially the global cumulative datacenter market up through 2024 being built in one year!” the authors write. But they argue their model “adjusts for” delays and shortages “and still points to a material acceleration in datacenter capacity in 2027.”
A reply to a “hunch”
The report is partly a response to Brad Gerstner of investment firm Altimeter. According to SemiAnalysis, Gerstner showed its data on the All-In podcast and argued its 2027 forecast was too high. “But let’s not operate on hunches,” the authors write.
Gerstner’s comments can be checked in a talk published on the All-In Podcast’s YouTube channel on 17 September. He cited a SemiAnalysis forecast that 43GW would be added “next year”. “I would suggest Dylan’s forecast” of 43 gigawatts “is too aggressive,” he said, according to the video’s automatic captions. “I don’t think we’re going to get there.” He put the likely total “somewhere closer to 25” gigawatts and called it “my hunch”. He pointed to permitting and local opposition, grid connection delays, shortages of skilled labour and power equipment that he said “is sold out”.
The new report’s headline figure, +50GW, is higher than the 43GW Gerstner discussed. The free preview does not explain the change. It also does not say directly whether the 50GW is a global or US figure. Gerstner discussed the 43GW in a US context, but SemiAnalysis compares its 50GW with the global market.
More than 24GW in advanced construction
SemiAnalysis’s main evidence is what is already being built. It says it has identified “>24GW of datacenters in advanced stage of construction, all to be delivered in 2027.” “Most of them are more than halfway done, with exterior cooling and electrical equipment already installed,” the report says. “That’s just 40 campuses, a tiny share of the multiple hundred sites in advanced stage of construction.” By TSN’s arithmetic, those 40 campuses alone would be close to half of the 50GW forecast.
The authors also say that “US hyperscalers have never launched more construction of datacenters”. They say the number of megawatts starting construction each quarter is rising sharply, “driven in particular by two hyperscalers”. They name those two only behind the paywall.
Nearly $1tn of leases signed
The second piece of evidence is leasing. Developers “typically only spend 5-10% of project capital without a customer,” SemiAnalysis says, so they need a pre-lease before building. “That’s typically a 15-20 year contract, with a TCV of $30-50B per GW,” it says. TCV means total contract value. Because these leases come before debt is raised, and debt comes before construction, SemiAnalysis treats them as an early signal of the buildout.
The report gives the 2026 total in two slightly different ways. One passage says: “Year-to-date, slightly under USD 1T of binding / non-cancellable datacenter leases have been signed.” Another says SemiAnalysis has “identified over a trillion USD of lease value that was signed and closed” in 2026 so far. (The report’s subtitle gives a higher figure, which the free text does not explain, so TSN has not used it.)
According to SemiAnalysis, Oracle “kicked off the era of gigantic leases, after closing on ~4.5GW of datacenter IT capacity across three sites between August and October 2025.” Since then, it says, “Meta, AWS, Microsoft, Google, Nvidia, AMD, Anthropic and OpenAI” have all been in the market for leases at gigawatt scale. There is also “a long tail of Neoclouds”, newer GPU cloud providers, “signing hundred-MW-scale deals”.
Faster builds and new power
SemiAnalysis says the industry is building faster by using simpler, prefabricated designs. It names Google’s modular electrical systems, Meta’s tent design and a fast-build design at AWS. “Construction timelines are now under 10 months,” it says. It adds that prefabrication can cut on-site mechanical, electrical and plumbing labour “up to 63%”.
It names Singapore-based developer DayOne as “likely the best example”. DayOne has “~3GW leased since their first deal in early 2023,” the report says. “While traditional developers have >18 months build timelines, DayOne cut this to ~9 months, which was key to signing huge deals with Firmus, OpenAI and Nvidia.”
On power, SemiAnalysis argues that on-site (“behind-the-meter”) generation and new suppliers mean “the power generation problem has broadly been solved”. It also says building outside the US is “sharply accelerating in 2027”.
The caveats
The authors accept that there are “plenty of challenges and shortages”, including labour, supply chain delays and fundraising. They say their model has called out delays before, including one at an Oracle site in New Mexico in April. In the paid part of the report, they say they consider whether the world faces an oversupply of data centres. They suggest that “memory and logic” chips could become “the new #1 constraint in 2027-28.”
The forecast is SemiAnalysis’s view, and the 50GW has not yet been built. Gerstner’s estimate of about 25GW is roughly half of it.
Sources
- SemiAnalysis: Datacenters 2027: The Year of Acceleration, +50GW in a Single Year, 19 October 2026 (free preview)
- All-In Podcast (YouTube): Brad Gerstner: No AI Bubble, Semis Eat the Nasdaq & AI’s Take Off Problem, 17 September 2026
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