[AI Era Electric Power is National Power]⑬ Underwater Data Centers, Which Even MS Failed at, Are Becoming a Reality

Reducing Cooling Costs... Lowering Electricity Consumption and Carbon Emissions
Building Facilities Capable of One-Month Stays at 30 Meters Depth
Plans for Future Construction of Hyperscale Complexes with 100,000 Servers

Exterior video of the Korean-style underwater space platform. Provided by the Korea Institute of Ocean Science and Technology

The idea of placing power-hungry data centers in the cold ocean has been gaining traction. According to research, underwater data centers can reduce power consumption by more than 50% compared to land-based data centers because they use seawater for cooling. Carbon emissions can be reduced by 12%, making them environmentally friendly.

Attempts have already been made by Microsoft (MS) in the United States and in China, and South Korea is also conducting a national research and development (R&D) project. A modular underwater structure capable of accommodating a person for a month at a depth of 30 meters is being installed, one of which is a data center. Through an interview with Han Taek-hee, principal researcher at the Korea Institute of Ocean Science and Technology, who has been in charge of the project since 2022, we examined the economic feasibility and R&D progress of underwater data centers.

- Why are underwater data centers necessary?

▲Data centers require enormous power to cool the heat generated by communication and computing servers inside. About 38% of the total power consumption of a data center is used to operate the cooling system. The water (coolant) used to operate the cooling system and carbon emissions are also increasing. To reduce cooling costs, Meta built a data center in Lule?, Sweden, near the Arctic, and Naver built one in Chuncheon, Gangwon Province. Naturally, the need for eco-friendly data centers that improve energy efficiency has increased.

Virtual image of the interior of the Korean-style underwater space platform. Provided by the Korea Institute of Ocean Science and Technology

- What happened to MS’s underwater data center?

▲MS was the first to conceive of a subsea data center that uses cold seawater to cool IT equipment. In 2015, MS conducted the first phase of a demonstration of an unmanned subsea data center off the Pacific coast of the United States. From 2018 to 2020, the second phase of the demonstration was carried out in the Orkney Islands, Ireland. Through these two demonstrations, it was found that the failure rate of underwater data centers was about one-eighth that of land-based data centers. However, problems occurred during the process of drawing seawater through pipes for cooling. Foreign substances accumulated inside the pipes, reducing cooling performance, and barnacles attached to the data center body, decreasing thermal efficiency. MS appears to have discontinued research on underwater data centers after the second demonstration.

- Did China’s underwater data center achieve results?

▲Chinese data center company Highlander also produced the first commercial underwater data center in 2023 and installed it near Hainan Island. The energy efficiency of data centers is measured by the PUE (Power Usage Effectiveness) index, where a PUE value of 1.0 means all power is used by IT equipment inside the center. Highlander’s underwater data center reportedly achieved a PUE of less than 1.1, significantly improving energy efficiency. The global average PUE for data centers in 2021 was 1.57. According to recent local reports, this data center is equivalent to a facility with 30,000 high-spec gaming PCs and can perform a year’s worth of standard computer calculations in just one second. DeepSeek has used this facility to enhance AI assistant services, and about 10 companies, including telecom operators and AI firms, are actually using it.

In 2020, Microsoft (MS) was seen retrieving its underwater data center above water. Researchers tested and monitored the performance and stability of the data center servers for two years. Official MS website.

- How far has domestic underwater data center research progressed?

▲The site for building the underwater data center was chosen near Sinri Port, Seosaeng-myeon, Ulju-gun, Ulsan, about 1,200 meters offshore. Since fishing rights have been lost there, there is no concern about complaints. Instead of seawater, special refrigerants will be used to prevent pipe clogging. Coatings that do not rust or allow barnacles to attach will be used for the exterior. When evaluating the heat dissipation performance of the underwater data center, it was found to be similar to the effect of installing it in Ulsan during winter. The resulting carbon reduction efficiency was 12.2%. Experiments were conducted to determine the appropriate pipe length, thickness, and flow velocity suitable for cooling heat generated by IT equipment. Experimental results also showed that there is no need to worry about seawater temperature rise due to the underwater data center. All designs have been completed, and orders for actual production are scheduled to begin by the end of this year. In particular, once the data center module technology is developed, research on building large-scale data center complexes will also be pursued.

- Please explain the research on building large-scale data center complexes.

▲This is a large project to build a hyperscale data center complex underwater with about 100,000 servers. It requires 105 cylindrical data centers about the size of a container box (5 meters in diameter and 10 meters in length). The total project cost is estimated at around 113 billion KRW, and private investment is essential. Compared to the Kakao Ansan data center, which has 120,000 servers and cost 143.6 billion KRW in construction, the construction cost can be reduced by about 20%, highlighting the economic feasibility of underwater data centers.