The Ocean Is Becoming a Server Farm. A Small Town in Maine Is Fighting Back.

7 min readHere’s what you’ll learn when you read this story:The local and environmental opposition to a proposed tidal-powered data center in Maine’s Passamaquoddy Bay is emblematic of increasing concerns over the hidden costs of putting servers underwater.Subsea data centers may emit 80 to 90 decibels of noise. Imagine a leaf blower or power tool running continuously.China’s in the game too, in a major way. It has launched a $226 million underwater data center off Shanghai.Pristine.That’s the word Dwayne Tomah uses to describe Passamaquoddy Bay, Maine’s tidal inlet that shares its name with his own ancestral tribe. Aside from being the tribe’s language keeper, Tomah is also director and curator of the local tribal museum in Sipayik, but recently he’s taken on another role: Being a voice against underwater data centers.“We tried to leave [the bay] the way it was in the beginning, but constantly we were having encroachment,” Tomah says. “It’s important that we pay attention to what’s happening.”In February 2026, a company named DeepGreen Western Passage SPV LLC applied for a preliminary permit with the Federal Energy Regulatory Commission (FERC), an independent agency housed under the Department of Energy that oversees interstate transmission of electricity, natural gas, and oil. The proposed plan was to leverage Passamaquoddy Bay’s 19-foot tides, some of the highest tides in the world, to power a data center housed in the bay itself. With very few underwater data centers in operation around the world—and only a couple powered using tidal energy—the idea is an ambitious one.And local opposition matched that ambition.Within a few months, packed town halls called for size restrictions and a general pause on data center construction led in part by the Eastport Coalition for Healthy Oceans (ECHO). In mid-August, the City Council unanimously enacted a 180-day moratorium on the underwater data center proposal; days later FERC accepted DeepGreen’s permit; and weeks after that, the environmental nonprofit Center for Biological Diversity filed a motion to intervene in the process because of possible impacts on endangered whales.Meanwhile, DeepGreen has also proposed a similar project near Anchorage, Alaska.“As an avid surf fisherman, I’ve always marveled at the immense power of the sea,” Louis Wolfson, managing member of DeepGreen, says in an email. “If you place sealed modular data servers on the seabed and power them with hydrokinetic tidal turbines, you solve the biggest issues facing data centers today: you don’t consume town land, you don’t drink up local water, and you generate your own clean power behind the meter.”In the artificial intelligence boom era, data centers have grown like weeds across the U.S. In some places, such as the state of Oregon, data centers consume 25 percent of the state’s total energy. In more arid regions of the U.S., data centers use millions of gallons of fresh water for cooling racks and racks of servers. That’s inspired some companies to look for places off-shore in the hopes of curtailing water usage while simultaneously plugging into renewable energy resources, whether offshore wind turbines or tidal energy.But the world’s oceans are already stressed from climate change and pollution, and environmentalists argue that placing data center infrastructure along the ocean floor could make a bad situation worse by introducing excess heat and noise into already vulnerable environments. Meanwhile, many residents in Eastport worry about its impact on local fishing and lobstering, a major economic force in the area.But the first practical question might be: Does it even make sense to put data centers underwater?***Although the dawn of artificial intelligence pushed the number of data centers in the U.S. to new, dizzying heights—the U.S. has ten times as many data centers as Germany, the country with the second most—the idea of underwater data centers actually predates the AI gold rush. In 2013 Microsoft employee Sean James, a former U.S. Navy submarine seaman, first proposed the idea of an underwater data center, and within two years, the company launched a Phase 1 prototype off the coast of California. They called this offshore compute venture Project Natick.Jonathan Banks/MicrosoftThe Northern Isles underwater datacenter was deployed 117 feet deep on the sea floor off the Orkney Islands in Scotland in 2018. The Project Natick team retrieved the datacenter in 2020. Algae, barnacles, and sea anemone grew on it during its two years underwater.Microsoft placed server racks in a gas-tight, tube-shaped container with thick steel walls. They then filled the container with inert nitrogen, which lacked the moisture and oxygen in normal air that could corrode the server components. In 2018, the company scaled up the operation and tested the servers in harsher oceanic conditions off the coast of the Orkney Islands in Scotland. Although the Phase 2 data center saw a decrease in failure rate and was powered using local renewable energy, Microsoft exhumed the now barnacle-encrusted data center in 2020 and confirmed in late 2024 that the company no longer deployed data centers underwater.While Project Natick was an exploratory test project, the idea lived on, and today numerous startups around the world have tried their hand at underwater data centers. The most high-profile of these attempts was first reported back in 2025 when Chinese startup HiCloud Technologies in partnership with the Chinese government launched a $226 million underwater data center off the coast of Shanghai. Like Project Natick, the data center is similarly tube-shaped, relies on nitrogen to protect servers from corrosion, is powered by wind turbines, and uses plentiful seawater as a natural cooling system.Other companies are also rushing to offshore AI. One firm based in Washington state hopes to develop floating data centers powered by waves while another in California wants to build floating wind turbines to power modular AI. NetworkOcean, a startup in San Francisco, planned to dunk a capsule of GPUs in San Francisco Bay before meeting pushback and ultimately pivoting to solar-powered floating data centers.Finally, Subsea Cloud, another U.S. company, has deployed more than 13,500 subsea servers in Southeast Asia along with a pilot program off the coast of Norway. Unlike Project Natick, Subsea can drop servers down as far as 3,000 meters, placing them near subsea cables for data connection and offshore wind projects for power while also adding a physical security layer only thousands of feet of ocean water can provide.Then, there’s DeepGreen. Similar to Microsoft’s design, DeepGreen’s system would use inert nitrogen in airtight containers—to remove moisture, oxidation, and rust—that would then line the seabed. With hydrokinetic tidal turbines powered by Passamaquoddy Bay’s 19-foot tides, the system runs mostly on its own, only switching to onshore battery energy storage systems or an onshore high-voltage transmission connection when tides slow down and switch direction.Connecting to renewable power is essential if these submarine facilities hope to address AI’s insatiable thirst for fresh water. According to a 2024 report by the Lawrence Berkeley National Laboratory, data centers use roughly 12 times more water for indirect power generation than for cooling, so while using the ocean as a heat sink cuts back on some freshwater usage, the real driver of water use is still power generation. In other words, pairing underwater data centers with renewable energy, whether wind, solar, wave, or tidal, is really the only way to make serious sustainability claims.Melissa Scanlan, a freshwater researcher at the University of Wisconsin-Milwaukee who’s studied water use and AI data centers, says that such underwater centers’ sustainability reports skip over reporting the water they consume just by creating power, and that’s concerning.At least for now, these underwater data centers are much smaller than data centers on land. The proposed DeepGreen pilot project in Maine will cover 27.1 acres with a power capacity of five megawatts. (By comparison, Amazon’s data center in Boardman, Oregon will be 1,300 acres with a one-gigawatt power capacity.) However, future submarine data centers could grow to upwards of 700-megawatt modular server farms, says Maxie Reynolds, founder of Subsea Cloud.But the hidden cost of underwater data centers could surpass any raw comparisons of water and power use.***In some ways, data centers near the coast could make sense. Not only for their power and serviceability, but because they have less impact on marine life than building data centers in the deeper ocean would, Andrew Sweetman, PhD, says. As leader of the Seafloor Ecology and Biogeochemistry research group at the Scottish Association for Marine Science in the U.K., Sweetman spends a lot of time studying the seafloor, trying to understand the human impacts on these sensitive ecosystems.“An estuary area is an environment that sees quite a dynamic range in environmental conditions daily, so the ecosystems are able to cope with lots of pressures,” he says, such as changing temperatures, salinity, and oxygen levels. Deeper environments tend to be more stable, and so are more sensitive to change, such as increased heat.Noise is another huge environmental nuisance, with land-based data centers known for emitting troublesome sounds that drive angry residents to city council meetings. Reynolds says that Subsea Cloud’s data centers emit noise levels up to 80 to 90 decibels; imagine a leaf blower or a power tool in constant operation.Citing noise pollution as a major concern, the Center for Biological Diversity filed a motion to stop DeepGreen’s preliminary permit in Passamaquoddy Bay. Creating increased traffic in the bay, whether for environmental assessments, server construction, or data center management, could imperil the endangered 400 North Atlantic right whales that still occupy these waters, according to the center’s press release.For now, DeepGreen’s preliminary permit is open to a 60-day comment period, which ends in late October. While Wolfson and Reynolds see the data centers as a sustainable option compared to their land-based alternatives, Tomah sees these underwater data centers as yet another “encroachment” on the pristine bay that’s so central to the history of his people. It remains a vibrant fishing and lobstering community whose tradition traces back more than 13,000 years.When he spoke against the data center, he “spoke on behalf of Putep—in our language, it means ‘whale,’” Tomah says. “I told them that this is going to affect them and that we must speak on behalf of the whales, the porpoise, the seals, all of the fish, all of the plants—everything is connected and everything is going to have a rippling effect. We’ve seen it time and time again.” He adds, “Until I’m set in the ground, I will continue to fight.”Download Pop Mech Digital IssuesDarren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.