Explore underwater data centers' viability, sustainability

Why are data centers being put into the ocean?

Data centers house and manage the vast amounts of information that people generate and consume every day. Site selection for modern data centers usually includes areas where electricity is inexpensive, the land is cheap and the facility doesn't impose on the local communities. Deployment of underwater data centers offers similar benefits, though some additional costs and downsides present significant barriers.

Examples of underwater data centers

Project Natick by Microsoft in 2015 and 2018 was one of the first underwater data centers. As of 2020, Microsoft put an end to Project Natick. Phase 1 in 2015 consisted of a small data center that underwent tests off the coast of California for 105 days. Phase 2 in 2018 was the deployment of a slightly bigger data center, called Northern Isles, set 117 feet (35.7 meters) deep on the seafloor off Scotland's coast for two years. It housed 864 servers in a vessel approximately 40 feet (12.2 meters) long and 9 feet (2.8 meters) in diameter with a low-pressure, dry nitrogen environment.

Another company, Subsea Cloud, designs and deploys commercially available underwater data centers. It uses nonpressurized "pods" for its servers, which contain a proprietary nonconductive liquid to protect the technology inside. Subsea Cloud claims its pods can withstand a depth up to 3,000 feet (914.4 meters). The pods use passive cooling methods, which reduce their carbon footprint and impact on the surrounding environment.

In 2023, Highlander, a company that specializes in underwater data centers, launched a commercial facility in the water near Hainan, China. The data center weighs about 1,433 tons (1,300 metric tons) and is about 115 feet (35 meters) underwater. The company plans to deploy 100 more modules in the near future to reduce land, fresh water and electricity use.

The benefits of underwater data centers

The use of underwater data centers leads to possible energy sustainability, low cost and less land use compared to large-scale data centers. There are multiple factors in enabling these benefits.

Abundant real estate and reduced latency

Approximately 40% of the human population lives within 62 miles (100 kilometers) of a coast. Companies can deploy data centers offshore if there is not enough land available for a facility. Underwater data centers near the coastline would be available to a large percentage of the population without occupying space for residential and commercial development.

Underwater data centers placed near densely populated coastal areas can reduce or eliminate latency over the network. Data would have a short distance to travel.

Cost savings through upfront investments

Most cloud servers have a five- to 10-year life span, while other infrastructure equipment is good for up to five years. Companies can purchase the hardware outright and only revisit purchases for new equipment once the life span ends.

Lower hardware failure rates

Tech hardware lasts longer underwater because humans don't jostle or bump into the containers. It also suffers from less corrosion when stored in dry nitrogen-based environments. Microsoft noted that the failure rate underwater was one-eighth of that on land.

Lower power needs and costs

Due to their smaller size and more efficient construction, underwater data centers use less power. They could be colocated with other offshore facilities, like sea-based wind farms that generate power through wind or sea wave action. Subsea Cloud taps into existing undersea cabling to power its pods, eliminating the need for new power sources.

No cooling costs

Deep-sea data centers use the ocean's cooling capacity to consistently maintain lower temperatures. There's no need for an active, energy-intensive mechanical cooling system since the surrounding water is naturally cooler than the hardware inside the vessel. Seawater is also a climate-friendly resource.

Reduced time to deployment

An underwater data center can be built and deployed in weeks as it is a manufacturing project. A manufacturing project uses existing industries and markets that work on faster timelines than one of a giant data center facility on land.

The downsides to underwater data centers

Although the experiments and benefits make underwater data centers seem like near-future and frequent deployments, they have downsides that make the idea unfeasible -- for now.

Accessibility for deployment and retrieval

Accessing the seabed might be a challenge, particularly in deep waters or areas prone to rough conditions. Underwater vessels can handle rough seas, but deployment vessels cannot.

Energy sources

Climate-friendly power sources are not always available. Offshore wind farms stop working on calm days, and wave-based generators might only work with waves above a certain size.

Physical security

The vessel's underwater location protects it against most criminals and trespassers. However, it is vulnerable to well-funded criminals and nation-state actors, who might find it easier to attack a facility not defended by traditional means.

Scalability

Because of its size, replicating a land-based data center underwater might not be possible by networking multiple ones together. It depends on other factors, like the hardware, power source and project requirements.

Seabed location and jurisdiction

The stability of the seafloor and the jurisdiction of the water are big factors when deciding on a location. Depending on the location, permitting to allow for these types of vessels and constructions might be an issue.

Vessel structure durability

Underwater data centers are restricted by size to the currently available construction methods and materials. Microsoft's test vessel was only 40 feet (12.2 meters) long and 9 feet (2.8 meters) in diameter, while Subsea Cloud's pods are about 20 feet (6 meters) long. Experts are unsure of how to build and deploy larger structures at scale that are safe enough for hardware.

Are underwater data centers environmentally sustainable?

Underwater data centers' environmental impact and means of sustainability are in question. Some experts believe they are sustainable, and others believe they are not.

Team Yes: Underwater data centers are sustainable

Climate-friendly power generation methods, such as tidal generators and offshore wind turbines, could power underwater data centers. Tidal generators are 100% renewable and have a small carbon footprint. Existing underwater cabling could provide power, which reduces the need for new underwater cabling.

The vessels are designed to be lights-out data centers, which means they can operate without physical or human interference. This increases sustainability because they can remain untouched for their life span.

Once their life spans are over, materials from the vessels and the hardware within can be recycled. The vessels also act as artificial reefs for marine life, reducing the need to create artificial reefs with sunken ships.

The emergence of underwater data centers is a shift in infrastructure and design. They offer a promising alternative to land-based facilities since they can harness the unique advantages of the underwater environment. Underwater data centers have the potential to completely change the way we design, deploy and operate them.

Team No: Underwater data centers are not sustainable

These projects place artificial materials underwater and could cause significant outgassing and other changes to the natural marine environment. Leaks of gases and nonconductive oils inside the vessels could harm ocean life. Any technology located within the vessels could also harm underwater life, as equipment is constructed of materials not naturally found in the sea.

Marine heat waves and climate change fluctuate sea and ocean water temperatures more than in the past. Rising or changing temperatures challenge underwater data centers as they can disrupt the effectiveness of seawater-based cooling systems, leading to server overheating and performance degradation. Lowered performance and other degradation mean they need to be resurfaced or upgraded often, increasing costs and damage to the local marine environment.

Julia Borgini is a freelance technical copywriter and content marketing strategist who helps B2B technology companies publish valuable content.