A Microsoft employee first came up with the idea of an underwater data centre in a whitepaper, and the company's artificial intelligence and research division took on the project in 2014. Data centres are the internet's backbone, storing huge amounts of information.
The wider goal with Project Natick is to deploy data centres at scale anywhere in the world within 90 days.
Most data centres can take anywhere from one to two years to deploy — but as more of the world comes online, it would be handy to speed this process up.
The company initially built a proof-of-concept vessel last year in the calm waters of California, which operated for 105 days. It was called Leona Philpot, after the character in Microsoft Xbox game "Halo."
After finding Leona Philpot stayed waterproof, Microsoft deployed the Northern Isles data centre off the coast of Scotland, which will be operational for up to five years.
Part of the reason Microsoft chose Orkney was because the islands are a hub for renewable energy research.
Microsoft teamed up with a French company, Naval Group, to build the new Northern Isles undersea centre.
Naval Group has expertise in building submarines, and it adapted a heat-exchange process normally used for cooling submarine vessels for cooling the data centre's 12 server racks.
An external shell covers the 864 servers and their cooling infrastructure. The data centre was assembled in France, then shipped to Scotland for deployment.
The whole structure is 40-foot long. That sounds big but the Northern Isles centre is actually much smaller than most data centres, which sometimes house up to 80,000 servers.
This particular data centre can store 5 million movies.
When it was time to put the data centre in the sea, it was attached to a ballast-filled base and towed out into the water.
Once it was in position and partially submerged, a remotely operated vehicle plugged the data centre to its power wiring and fibre optic cable running from Orkey. It was then switched on.
Here it is being fully submerged in the water.
Then the data centre had to be lowered 117 feet to the sea floor — hopefully without springing a leak. That involved 10 winches, a crane, a gantry barge, and a remotely operated vehicle.
Microsoft's team will keep an eye on the data centre over the next year, keeping tabs on power consumption, internal humidity levels, sound, and temperature levels.
This is just a research project, so undersea data centres might not become commonplace.
"When you go for a moonshot, you might not ever get to the moon," said research VP Peter Lee said. "It is great if you do, but, regardless, you learn a lot and there are unexpected spinoffs along the way."
Watch Microsoft's video about Project Natick below.
