Underwater AI data centers are being proposed for real ocean waters before anyone knows what they do to the ecosystems around them. DeepGreen, the company behind the contested Eastport, Maine project, now wants to build a 100-megawatt underwater AI data center in Alaska's Cook Inlet, off Nikiski. The plan calls for 66 subsea data center "hives" powered by 330 to 350 tidal turbines across about 1,650 acres. FERC accepted the preliminary permit application for filing on September 4, 2026, and nothing has been approved.
The pitch is that cold ocean water cools the servers and tidal energy powers them, so the facility avoids the freshwater and fossil fuel problems of land-based data centers. But the environmental science is thin. We don't know how much heat these facilities add to surrounding water, how far that heat spreads, or how anyone repairs a failure on the seafloor in one of the strongest tidal currents in the country. Cook Inlet is also home to an endangered beluga population that has fallen from about 1,300 animals to about 330, and to Alaska Native communities who depend on its fisheries.
Andrew walks through what's in the filing and who's raising questions. The CEO of the Alaska Energy Authority says DeepGreen never contacted his agency, even though the filing says the project would tie into AEA's $400 million Cook Inlet PowerLink. Kenai's city manager says the council hasn't discussed it yet. In Eastport, the Passamaquoddy Tribe at Sipayik turned down DeepGreen's offer of free power and the city passed a 180-day moratorium. FERC is taking public comments on the Cook Inlet project until November 2, 2026, docket P-15423-000, and anyone can submit one.
Chapters:
0:42 – Why Put an AI Data Center Underwater?
3:54 – Free Tidal Power Offered, and Refused
7:09 – A Pattern Near Indigenous Communities
10:37 – What Happens When Something Breaks Underwater?
14:03 – Your Chance to Comment
Watch the Eastport, Maine episode for the first half of this story: https://youtu.be/M5WAs3WGw6Q
Takeaways:
DeepGreen has applied for a FERC preliminary permit to study a 100 MW underwater AI data center in Cook Inlet, Alaska: 66 subsea hives, 330 to 350 tidal turbines, about 1,650 acres near Nikiski.
A preliminary permit lets a company study a site. It does not approve construction.
The environmental effects of underwater data centers are largely unstudied, including local warming, noise from turbines, and the risk of leaks or failures that are hard to reach and repair.
Cook Inlet belugas are endangered, down from about 1,300 animals to about 330 in NOAA's 2022 survey.
Alaska Energy Authority CEO Curtis Thayer says DeepGreen never contacted AEA, and AEA plans to intervene in opposition.
DeepGreen's earlier Eastport, Maine proposal shrank from 51 MW to 15 MW under pushback and now faces a 180-day moratorium; the Passamaquoddy Tribe at Sipayik rejected an offer of free tidal power.
Recent polls show broad public opposition to local AI data centers (Gallup 7 in 10 against; Heatmap Pro 75% opposed; UMass Amherst 65% opposed, 11% in favor). No polling yet covers underwater data centers.
Public comments are open until November 2, 2026 at 5 p.m. Eastern. Submit at ferconline.ferc.gov/QuickComment.aspx using docket P-15423-000.
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