Every time we ask something of an AI, the scene seems almost invisible: we type a sentence, receive a response, and move on. But behind that apparent lightness there are buildings full of servers, cooling systems running tirelessly, and an electricity demand that does not stop growing. The cloud, no matter how much we call it a cloud, has ground, cables, heat and consumption. And precisely for this reason an idea that not so long ago sounded like a strange experiment is beginning to make sense: removing part of that infrastructure from land and taking it to the sea.
China is already taking it to the commercial field. MERICS notes that the country has presented the first commercial underwater data center in Hainan and a module powered by offshore wind energy in Shanghai, two movements that point in the same direction: to see if this architecture can stop being a technical oddity and become a usable piece within its digital deployment. The novelty is not only in submerging servers, but in presenting them as a possible response to three tensions that already weigh on the AI infrastructure: energy, cooling and land.
Hainan is the first piece of that leap. Pilot testing of the Hainan underwater data center began in 2023, first with storage services for the island’s free trade port and telecom operators, before expanding to cloud and AI companies. The project does not play in the league of large terrestrial data centers, but it does have sufficient scale to stop being a simple model: each cabin is located 35 meters under water, has 24 racks and can house up to 500 servers. Its value is precisely there: demonstrating that China is trying to turn an experimental idea into real commercial infrastructure.
Shanghai as an energy showcase. If Hainan represents the commercial leap, Shanghai adds the piece that makes the story more ambitious: direct integration with offshore wind energy. This project is facing Lingang, where CGTN places an underwater platform already operational and directly connected to a nearby offshore wind farm. The total planned investment is 1.6 billion yuan, about 235 million dollars according to that source, and the installation is based on a pilot phase of 2.3 MW, while the complete project is planned to reach 24 MW.
Refrigerate without fighting against the environment. That is the technical promise that explains much of the interest in these underwater data centers. The Chinese state media recalls that terrestrial facilities can dedicate up to 40% of their electricity to cooling, a problem that is especially visible when we talk about increasingly dense racks. Under the sea, the idea changes: take advantage of water as a natural heat sink. In Shanghai, for example, the average sea temperature is around 15 degrees Celsius.
The other half of the equation is energy. The Shanghai center is connected by a photoelectric composite cable to a 200 MW offshore wind farm, with more than 50 turbines, and more than 95% of its electricity comes from renewable energy. If the project reaches full scale, it is estimated that it could save 61 million kWh per year and significantly reduce its carbon emissions.
There are challenges too. MERICS warns that these data centers pose significant challenges: sealing modules, dealing with seawater corrosion, operating in a high-pressure environment, and assuming that maintenance may require bringing entire modules to the surface. This is no secret. Accessing submerged hardware in the event of a failure is one of the most sensitive points.
Microsoft had already tried the path. The best known antecedent is Project Natickan initiative with which Microsoft submerged a data center off the Orkney Islands, in Scotland, and recovered it in 2020 after two years of operation underwater. The test served to demonstrate that the idea could work technically.but it did not end up becoming a commercial line.
Reading is not a magic solution. As we can see, China is trying another way of dividing up the pieces of the problem. Hainan shows attempt to bring underwater data centers into commercial arena; Shanghai adds a broader ambition, connecting them with offshore wind energy and directing them towards increasingly demanding loads. Undersea data centers seemed like a technological oddity. Now, at least in China, they are beginning to look like an industrial bet with a much more ambitious mission.
Images | Shanghai Hailanyun Technology
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