China tests underwater data centres to reduce AI carbon footprint (www.scmp.com)

A Chinese firm, Highlander, is preparing to sink a large yellow pod of servers off Shanghai by mid‑October as part of one of the first commercial underwater data‑centre trials. The capsule — built with state‑owned construction partners and finished on a wharf near the city — uses ambient ocean currents to cool servers instead of energy‑intensive air conditioning or evaporative systems. Highlander’s vice‑president says undersea cooling can cut roughly 90% of the energy used for cooling, echoing an earlier Microsoft prototype off Scotland in 2018 but aimed at broader commercial service. The project matters because AI workloads are driving huge growth in data‑centre power use, and cooling is a major slice of that energy bill and carbon footprint. If reliable at scale, subsea hosting could lower power‑usage effectiveness (PUE), enable higher rack densities, and reduce emissions for coastal deployments. However, technical and commercial hurdles remain: corrosion, maintenance and retrieval logistics, subsea networking and latency, regulatory and environmental risks from heat discharge and marine impacts, and upfront costs. The trial will test whether the theoretical cooling and carbon benefits translate into a practical, scalable alternative to land‑based facilities for AI and cloud providers.