“Bring a GPT – 3.5 in 24 hours”: in China, servers under the sea to cool the AI

To deal with the exponential calculation demand linked to Artificial intelligenceChina builds a data center … under the sea. 6 km off Shanghai, this unprecedented project aims to naturally cool the servers while reducing freshwater consumption. A technological feat to the airs of geopolitical manifesto, while the United States brake on a similar concept.

Cool artificial intelligence under the sea, the technological (and political) bet of China

Launched in June 2025, the project was controlled by Halalyyun Technology, a Chinese company sometimes called “Hicloud”. It is based on a simple idea: to immerse the servers in the ocean to take advantage of the natural cold of sea depths. The first module, operational in September, is installed in an airtight box 6 kilometers from the coasts of Shanghai.

This module will contain 198 IA servers racks, the equivalent of 396 to 792 high performance machines, capable-depending on the company-to cause a model like GPT-3.5 … in one day. The set is connected to an offshore wind farm, which should provide 97 % of the necessary electricity.

Compared to a terrestrial data center, energy consumption is reduced by at least 30 % thanks to passive cooling by sea water. No more evaporation towers, pulsed air systems, and especially the consumption of hundreds of thousands of liters of fresh water per day. A priority in China, where the resource becomes critical in certain provinces.

An American idea relaunched … Chinese

The concept is not new. In 2018, Microsoft launched Project Natick, a prototype of data center immersed off the coast of Scotland. Result: better reliability of servers (thanks to a stable environment, sealed and filled with nitrogen), real energy efficiency … but no commercial suite. Microsoft has since suspended the project, just saying that he remains “a research platform”.

Meanwhile, China has accelerated. Less than 30 months after a prototype off Hainan, Halaalyun is already going to the industrial phase. The company ultimately plans to deploy a network of underwater, autonomous modular centers, supplied with renewable energies.

But this strategy is not without gray areas. A study From 2022 showed that a slightly warmed water rejection during a marine heat wave, could impoverish in oxygen the surrounding waters, a risk for biodiversity. Microsoft, during his tests, had observed a warming of a few thousandths of degrees around his capsule. Minimal, but to watch.

Another sensitive point: physical cybersecurity. A 2024 study has shown that an underwater acoustic system could damage servers via targeted waves. A theoretical risk, but sufficient to ask the question of the vulnerability of these infrastructures in the event of geopolitical tensions.

Finally, other countries are positioned: South Korea has announced a similar project, and Japan like Singapore explore the idea of ​​floating centers on the surface. The era of amphibious servers seems to be launched.

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