China has deployed 250 AI data centres operating or under construction, a significant increase from the 60 recorded at the end of 2023, according to Scroll. This expansion is driven by the rapid growth of the country's smart economy and artificial intelligence sector. Local governments and technology firms are increasingly turning to underwater installations as a sustainable alternative to land-based facilities, which face rising pressure regarding land use and resource consumption.
The primary advantage of these offshore facilities is their use of seawater for cooling, a process that eliminates the need for fresh water and reduces total power usage by 18% to 28% compared to on-land equivalents. A joint project off Shanghai’s Lingang, valued at CNY 1.6 billion, is connected directly to adjacent wind turbines, allowing it to draw 95% of its power from renewable sources. The facility pumps seawater through heat exchangers to absorb heat from servers before releasing the warmed water back into the ocean.
Despite these efficiency gains, marine scientists express concern about the ecological footprint. Stephen Watson, a researcher at Plymouth Marine Laboratory, noted that the heat released could affect species in the immediate vicinity that cannot easily move away. John Abraham, a professor at the University of St. Thomas, described the ecological risk as real but geographically limited, warning that a four to five-degree Celsius temperature increase could stress organisms near their thermal limits during summer months.
Additional environmental challenges include the use of anti-fouling paints, which may flake off and pollute beaches or enter the food chain. The head of the China Sustainable Development and Marine Economy Institute, Hu Zhenyu, pointed out that current environmental impact assessments often focus on the construction phase rather than long-term operational or decommissioning effects. He also highlighted the higher maintenance costs associated with underwater infrastructure, where replacing microchips or repairing cable damage after storms can take days or weeks.
While competitors in Singapore, Korea, and the US are exploring similar seawater cooling technologies, Hu Zhenyu cautioned that commercial viability for underwater data centres remains unproven. He suggested that these facilities could serve as a complement to on-land centres, helping to utilize excess renewable energy, but emphasized that transparency in reporting environmental data is still lacking in the industry.