The San Francisco startup has a plan that sounds like science fiction: floating data centers powered by small nuclear reactors, moored offshore to feed artificial intelligence's relentless demand for electricity. Atomarine, backed by Y Combinator, says it will deploy 75-to-100-megawatt barges starting with a 2028 pilot running on natural gas before transitioning to nuclear.
It's an audacious proposal, even by Silicon Valley standards. CEO Dimitris Koutentakis, who holds four degrees from MIT and worked at Arrowstreet Capital and Amazon, founded the company with CTO Emile Germonpre, a nuclear engineer with a PhD from Ghent University. The two-person team is already pursuing partnerships with offshore barge builders and multiple vendors of small modular reactors, according to company materials. They envision each shipyard eventually churning out 1.5 gigawatts of capacity per year, with barges designed to operate for two to four decades.
The premise rests on a collision that's already underway. The International Energy Agency projected in 2026 that data centers worldwide would consume roughly 485 terawatt-hours in 2025, with that figure expected to nearly double to 950 TWh by 2030—about three percent of global demand. In the United States, S&P Global Market Intelligence expects data center load to jump from 366 TWh last year to 728 TWh by decade's end, based on a report from its 451 Research division.
"Every data center... is power constrained," NVIDIA CEO Jensen Huang said at his GTC keynote in mid-2026. "This is your AI factory." At a Morgan Stanley session earlier that year, he added that "tokens per watt becomes the single most important metric."
Yet the infrastructure to deliver that power is lagging badly. A June 2026 report from Lawrence Berkeley National Laboratory found the median time from interconnection request to commercial operation now exceeds five years for projects built recently, with roughly 8,200 projects seeking grid connection at the end of last year. High-voltage transmission lines take an average of ten years to complete, according to the Department of Energy's 2024 assessment, though the range spans five to 17 years depending on the project.
Community pushback is making things worse. McKinsey noted in August 2026 that local opposition was delaying data center projects, with community resistance emerging as a significant constraint on deployment in the first quarter alone. The city of Lowell, Massachusetts, imposed a year-long moratorium on new facilities amid noise and air pollution complaints from backup generators, WBUR reported. A Michigan utility approved a 12-month ban on supplying water to data centers after local proposals consuming hundreds of thousands of gallons per day sparked organized resistance. An NBC poll cited by The Atlantic in a September 2026 feature on the "Data-Center Rebellion" found nearly 70 percent of respondents oppose a data center in their area.
That groundswell of resistance is one reason Atomarine and other companies are looking seaward.
Why Offshore?
Three forces are converging to make the ocean look appealing: AI's staggering power density, regulatory gridlock on land, and the thermodynamic advantages of seawater cooling.
AI accelerators have pushed rack power densities far beyond traditional server loads. A June 2026 framework from ASHRAE, NEMA, and the Pacific Northwest National Laboratory noted that AI racks now draw "several hundred kilowatts," with megawatt-class racks anticipated. TrendForce reported in August 2026 that liquid cooling penetration among AI chips hit 53 percent last year and is projected to reach roughly 60 percent this year. The Uptime Institute's July 2026 survey found modal rack density surpassed 11 kilowatts, with operators reporting rising high-density footprints.
The capital expenditure is staggering. Dell'Oro Group said in August 2026 that data center capex could exceed $3 trillion cumulatively by 2030, with AI accelerators remaining the largest driver. TrendForce warned in September of a significant "power gap" by 2030, projecting deliverable capacity of roughly 223 gigawatts versus demand of approximately 491 gigawatts, based on its methodology tracking shipments and rising system draw.
Seawater offers a thermodynamic edge that's hard to ignore. The ASHRAE framework suggested well-designed liquid-cooled facilities can approach a power usage effectiveness of 1.10. Microsoft's Project Natick underwater pilot, which ran from 2018 to 2020, achieved a PUE of 1.07 and recorded a server failure rate one-eighth that of a land-based control group, according to results published at the time. Atomarine says it is targeting a PUE below 1.1 via seawater cooling.
Regulatory frameworks for maritime nuclear applications are evolving, with the Nuclear Regulatory Commission and U.S. Coast Guard developing coordination mechanisms for floating nuclear power plants and nuclear propulsion. The Coast Guard established a Maritime Nuclear Policy Division in November 2025. The Maritime Administration published a request for information in May 2026, seeking input on small modular reactors in the Marine Transportation System, including questions on liability frameworks, insurance pathways, port acceptance, and standards integration. The International Maritime Organization's Ship Design and Construction subcommittee is targeting adoption of a revised Nuclear Code by 2030, according to an IMO announcement.
The Department of Energy awarded $2.7 billion in January 2026 to expand domestic uranium enrichment capacity, addressing the high-assay low-enriched uranium fuel supply chain that advanced reactors require. Centrus Energy signed multiple HALEU supply contracts in mid-2026.
Who Else Is Trying This?
Atomarine is far from alone in betting on offshore AI infrastructure or nuclear-powered data centers, though it may be the first to combine both in a single venture.
Blue Energy and Crusoe announced plans in 2025 for a 1.5-gigawatt AI data center campus at the Port of Victoria, Texas, with natural gas power bridging to nuclear by 2031. Jake Jurewicz, Blue Energy's CEO, said the goal is to "build a plant with cost and schedule certainty." Andrew Likens, Crusoe's vice president of energy infrastructure, said "Blue Energy's gas-to-nuclear approach delivers exactly what we need... abundant, reliable, and clean power." The project filed an SEC amendment in May 2026 reiterating the 2028-to-2031 timeline.
Offshore pilots are advancing on multiple continents. Seatrium, a Singapore-based marine engineering firm, announced a 30-megawatt offshore data center pilot in July 2026, with public materials indicating nuclear powerships as a future option. NYK Line, NTT Facilities, and partners launched a floating green data center demonstration at Yokohama's Ōsanbashi Pier in March 2026, running a one-year trial through March 2027 with 100 percent renewable energy from solar panels and battery storage.
Mocean Energy in Scotland unveiled its Blue Core concept in 2026, combining wave power, offshore solar, and batteries to power modular AI data centers at sea, with a small-scale demonstration targeted for 2027. Nautilus Data Technologies commissioned a floating barge data center in Stockton, California, in 2020 and 2021, marketing "zero-water consumption" cooling; Black & Veatch noted the facility's low PUE. Nautilus offered the Stockton barge for sale at $45 million in November 2024.
On land, Westinghouse Electric announced a memorandum of understanding with Data4 in March 2025 to explore using the AP300 small modular reactor for European data centers. The NRC accepted Westinghouse's AP300 pre-application in 2023. NuScale Power received standard design approval for its uprated US460 design in May 2025. GE-Hitachi's BWRX-300 is in combined construction permit and operating license review for Tennessee Valley Authority's Oak Ridge project. X-energy reached a licensing milestone for its HALEU fuel facility in February 2026.
The American Bureau of Shipping issued an approval in principle in July 2026 for a Korean Research Institute of Ships and Ocean Engineering and Korea Atomic Energy Research Institute design for a 15,000-TEU molten salt reactor-powered container ship, signaling progress in shipboard nuclear certification. CORE POWER signed a memorandum of cooperation with the Port of Corpus Christi in August 2026 for maritime nuclear readiness studies and submitted a response to MARAD's SMR request for information that same month.
Challenges and Unknowns
Atomarine's 2028 gas-pilot timeline positions it to gather operational data before a nuclear transition that depends on regulatory approvals, SMR vendor selection, and port acceptance, all variables with multi-year lead times. The IMO's 2030 target for a revised Nuclear Code suggests international frameworks are still in development. U.S. NRC and Coast Guard coordination is ongoing but not yet codified into final rules for commercial floating nuclear platforms.
The company says deployment will be "4x faster" than land-based construction, a claim tied to shipyard modularity and the avoidance of site-specific interconnection queues and local permitting battles. PJM Interconnection reported in 2026 that it is preparing for data center load growth of up to 30 gigawatts between 2025 and 2030 and launched a Large Load initiative and Expedited Interconnection Track to accommodate the demand, but near-term capacity remains constrained.
Offshore deployments face engineering challenges absent from terrestrial sites. Tom's Hardware noted last summer that storms, corrosion, motion effects on high-density GPU racks, undersea cable connectivity, and SMR shipboard certification timelines all present reliability and cost uncertainties. Idaho National Laboratory and the Nuclear Research and Industrial Collaboration office estimated in a 2025 roadmap that a potential U.S. market for advanced-reactor-powered floating data centers could range from roughly two to nine units by 2050—a wide scenario band reflecting regulatory and market uncertainty.
HALEU fuel supply is ramping but not yet at broad commercial scale. DOE's January 2026 awards and Centrus contracts indicate momentum, but volume production timelines remain critical. Marine engineering for megawatt-class GPU racks, accounting for humidity, physical security at sea, and cyber resilience, will require hardened designs that ongoing pilots in Singapore, Japan, and Scotland will inform.
For AI infrastructure operators facing seven-to-ten-year timelines to connect new load to the grid and community opposition killing projects at rates Atomarine claims exceed 50 percent in recent years, the ocean represents a regulatory arbitrage play. U.S. Army Corps of Engineers Section 10 and Clean Water Act Section 404 mechanisms govern moorings and discharges in navigable waters, with nationwide and regional general permits reissued in 2026. State water boards regulate thermal discharge, as evidenced by regulatory oversight actions against Nautilus's Stockton barge in 2024 for missed temperature monitoring.
Debra Phillips, CEO of the National Electrical Manufacturers Association, said in the June 2026 ASHRAE framework release that "power distribution infrastructure must be coordinated with cooling and thermal management to maximize safety, reliability, and efficiency outcomes." That coordination is harder when the data center is moored three miles offshore, but it bypasses the local zoning hearings and neighborhood opposition that have become the defining constraint on AI buildout.
TrendForce's September analysis of the data center power gap and McKinsey's August note on postponed projects suggest the industry is running out of easy sites with available power and community support. Atomarine and its offshore peers are testing whether the difficulty of building at sea is less than the impossibility of building on land. Whether floating reactors become the answer to AI's power problem or a footnote in the annals of ambitious energy ideas remains to be seen, perhaps more than the founders expected when they first sketched the concept. The ocean is unforgiving, and so are the timelines for nuclear certification.
