A hunch said 25 gigawatts; the concrete says more

SemiAnalysis has published its datacentre outlook for 2027, forecasting more than 50 gigawatts added in a single year, with 60 gigawatts under construction and, by its count, 1.3 trillion dollars of lease contracts signed so far this year. The firm frames the piece as an answer to a specific public doubt rather than as a projection in the abstract.

The doubt was aired on the All-In Podcast, where Brad Gerstner of Altimeter showed SemiAnalysis's own data and said its forecast of plus 43 gigawatts for 2027 was too aggressive, putting the figure closer to 25 gigawatts — about half — on what he described as a hunch. The response is methodological: the firm says it cares about the truth rather than the narrative, and offers construction status in place of argument.

What it offers is a count. More than 24 gigawatts of datacentres sit in an advanced stage of construction and are due for delivery in 2027, most of them more than halfway done, with exterior cooling and electrical equipment already installed. That figure covers just 40 campuses out of several hundred sites the firm tracks at a comparable stage. Named examples include Crusoe's build in Abilene, Amazon Web Services in Indiana, and the QTS and Microsoft site in Georgia.

The analysts do not dismiss the constraints. They list power, labour, supply chains and capital, and have written separately on modular datacentres, electrical and cooling systems, behind-the-meter power and United States grid limits. Their claim is narrower than optimism: that very large sites are being completed, many of them on time, and that the binding shortage may move from power to chips. All of it is their assessment, and the underlying data sits behind their paid model.