Video: Microsoft shows of its Project Natick underwater datacenter. Source: Microsoft/YouTube

Microsoft has dropped a 40-foot long data-center pod onto the seafloor off the coast from the European Marine Energy Centre in Orkney, north of Scotland.

That's a fairly remote location, but Microsoft's thinking behind phase two of its data-center-in-the-sea research, Project Natick, is to bring its cloud servers closer to where people live.

Since half the world's population lives within 120 miles of the coast, it thinks offshore data centers could be an efficient, low-latency way of delivering AI applications and gaming content to end users.

Microsoft dropped a slightly smaller 30-foot Natick pod off the coast of California in 2016 to test whether it could run Azure services from the seabed.

Microsoft designed the pod to operate without maintenance for up to five years -- about the time it would take before the servers inside would be retired anyway.

See: Special report: The cloud v. data center decision (free PDF)

The prepackaged undersea data centers could also cut deployment times from two years to 90 days. Microsoft wanted to test whether its European vessel could make this deadline "from decision to power on", according to its updated FAQ .

As Project Natick engineers argued in a recent article in IEEE Spectrum, the advantage of shorter deployment times is they could allow Microsoft to be reactive to demand for increased capacity, rather than having to build data centers in anticipation of future demand.

They envision deploying a collection of undersea pods, each with several thousand servers, and adding to them as required.

According to Naval Group, the French defense naval-systems contractor that built Microsoft's pod, the data center has a payload of 12 racks containing 864 servers with a cooling system.

After assembly, it was moved by truck to Scotland, from where it was dragged out to sea on a raft and then carefully lowered 117 feet, 35.6 meters, to a rock slab on the seabed.

Although the data center is built to last five years, it will remain on the seabed for at least a year as Microsoft observes how it fares.

The pod is attached by a cable leading back to the Orkney Islands electricity grid, which supplies 100 percent renewable wind and solar energy to about 10,000 residents. The data center itself needs a quarter of a megawatt.

The Natick team also explained the pod's cooling system and how it uses ocean water to cool liquids inside the system.

"The interior of the data-center pod consists of standard computer racks with attached heat exchangers, which transfer the heat from the air to some liquid, likely ordinary water," they said.

"That liquid is then pumped to heat exchangers on the outside of the pod, which in turn transfer the heat to the surrounding ocean. The cooled transfer liquid then returns to the internal heat exchangers to repeat the cycle."

Image: Frank Betermin/Naval Group

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