Microsoft is evaluating the long-term prospects of underwater data centers, in a bid to cut latencies, improve service, and take advantage of some of the ocean’s unique characteristics. Saltwater and electronics aren’t historically considered to be great friends, but Microsoft’s prototypes are performing impressively well.

There are several hypothetical advantages to dropping data centers in the deep (relatively speaking). Air conditioning and cooling costs eat a sizable percentage of a data center’s budget. Water is far more effective at removing heat than forced-air cooling; deploying servers in the ocean would eliminate cooling overhead. Microsoft is reportedly considering deploying the servers with their own surface turbines or tidal energy systems to generate power on-site. While this would make the system less likely to be affected by land-based blackouts, it also increases the complexity and overhead of operation.

Microsoft is touting other advantages of this effort, codenamed Project Natick. Because half the world’s population lives within 50km of an ocean, deploying water-based servers would allow companies to offer guaranteed low-latency connections to large groups of people. The data centers themselves would be deployed quickly, possibly within three months. That’s far less time than it normally takes to build or scale out a data center, and the new systems could be integrated with existing land-based servers.

Microsoft recently built and tested a prototype system, which operated for 105 days underwater and experienced no problems. The system worked so well, in fact, that the engineers extended its operating time and used it to run some commercial workloads from Microsoft’s Azure cloud computing service. The company is now working on an underwater system 3x larger than the first prototype and will partner with an unchosen developer of alternative-energy systems that utilize ocean / wave power.

There have been some concerns about using the oceans as waste heat disepnsers for data centers. While a few local units would make no difference, it’s easy to imagine that a large data center cluster could have a significant impact on a local marine ecosystem — these computers generate tremendous amounts of heat.

Microsoft has stated that its end goal is to create data centers that are recyclable and do not impact the local environment. In theory, this should be possible, depending on how much waste heat each chassis produces. Closed-loop coolers would still allow for heat exchange between the server pod and the water without pumping seawater in and out of the system (and dealing with the associated corrosion and filtering issues).

Will companies adopt this sort of solution? It’s still too early to tell. Microsoft is far from the first company to propose an underwater server concept, but to date, manufacturers keep opting to plunk them down on land.