Lingang, Shanghai, China (HiCloud offshore underwater data centre)
#00220
Case study of
#00212 Relocate compute into submerged or floating offshore modules cooled by seawater
Implementer
HiCloud Technology, with Shenergy Group, Shanghai Telecom and CCCC Third Harbor Engineering
Timeline
Since Oct 1, 2025
Location
Description
The only commercial-scale underwater data centre in operation as of 2026. Servers sit in sealed watertight units offshore from Lingang, positioned between phases of an existing offshore wind farm; construction completed October 2025 and full commercial operations reported from May 2026.
The decisive design choice is siting inside the wind farm rather than immersion itself. The reported PUE of 1.15 and the claimed 22.8% electricity reduction against a conventional facility derive from removing the chiller plant; the claimed 100% wind supply comes from co-location. A land-based facility inside the same wind farm would capture the larger share of the benefit.
Phase 1 is 2.3 MW and the full build is 24 MW (~2,000 servers). At $226 million for 24 MW this is not obviously cheap relative to terrestrial hyperscale.
An earlier Chinese deployment, Highlander's shallow-water unit off Lingshui, Hainan (completed December 2022), reported an 80% cost reduction against deep-water designs and named China Telecom and SenseTime as customers.
No measured environmental monitoring data (thermal plume extent, benthic effects, biofouling rates) has been published for either site.
Metrics
6Funding
Lessons learned
- Co-location with offshore wind generation, not immersion itself, produces most of the measured efficiency benefit. The transferable lesson is about siting next to the power source, which works equally well on land.
- At 24 MW and $226 million, this demonstrates technical feasibility rather than economic competitiveness with terrestrial hyperscale; feasibility at this scale should not be extrapolated to gigawatt-class AI demand.
- Shallow-water designs are reported as substantially cheaper than deep-water ones, which identifies where engineering effort belongs if this approach is pursued elsewhere.
- Two years into commercial operation there is still no published thermal plume or benthic monitoring data. Environmental consenting regimes in other jurisdictions should require this data as a permit condition, since it does not appear to be produced voluntarily.
Sources
3Documented Jul 28, 2026