Data centres: the controversial frontier beneath the seas
These systems reduce energy consumption but raise other sustainability issues. However, research is making progress
Key points
Wave-powered floating balloons, underwater cylinders or wind-powered offshore platforms, from the United States to the North Sea. These are just some of the alternative solutions that form the basis of the technologies designed to underpin the economy of the future, in an effort to make it more sustainable. But today it is China that is leading the race to harness the oceans to reduce the impact of artificial intelligence on the planet.
Record consumption
Demand is growing at a staggering rate. In 2025, AI data centres consumed nearly 450 TWh worldwide, a figure which, according to estimates, could double within five years. In Italia alone, Terna recorded requests for connection to the electricity grid totalling 95.38 gigawatts in mid-August this year. Five years ago, the figures stood at around one gigawatt. The heat required to generate computing power, combined with the impact in terms of land use, calls for more sustainable solutions, particularly in light of the growing protests that have now reached Italia too.
Energy saving
The Chinese company HiCloud has ushered in the era of commercial exploitation of the seas, having launched the world’s first undersea data centre in June. With an investment of $225 million, the facility, off the coast of Hainan Island, uses seawater for cooling, reducing energy consumption by a third, and draws power from a 24 MW offshore wind farm, housing nearly 2,000 servers with a power usage effectiveness (PUE) of less than 1.15, where 1.0 represents perfect theoretical efficiency.
The idea of placing data centres underwater is not a new one. Microsoft had already experimented with submerging containers off the coast of Scotland between 2018 and 2020: the results had been promising, but the project was put on hold, partly due to regulatory uncertainties.
Warmer waters
Underwater projects continue to face difficulties relating to maintenance – which requires the structures to be brought to the surface – as well as serious concerns about their environmental impact on seas and oceans. In the waters around the Chinese facility, a temperature rise of almost one degree has been recorded, in an ecosystem already under pressure from record ocean warming, with effects on water acidity and oxygen levels and potentially serious consequences for the marine environment.
