Google sees the future of computing at sea.
The search giant has filed a patent for a "floating data center" that uses wave motion to power on-board computers and the ocean's water to cool them.
The patent was submitted in February last year but was spotted in the U.S. Patent & Trademark office's electronic filings and posted at Slashdot on Saturday.
The system Google engineers sketch out is a self-powered data center placed three to seven miles offshore, potentially operating off the grid. Standard shipping containers would house racks of computers that could be transported by truck and placed onto a boat by crane.
A wave-power generator would be the primary source of electricity. But wind turbines could be used to, for example, run water pumps and a tidal power generator could be used in rivers.
The patent specifies the use of a so-called Pelamis machine, which uses pontoons with pumps to convert wave motion into electricity. A British company, Pelamis Wave Power, is operating a prototype in Scotland and intends to install one off Portugal.
Google engineers calculate that an array of pontoons spread over a square kilometer (a bit more than a half mile) could produce 30 megawatts of electricity, enough to operate a single system.
Also envisioned is equipment to use theelectricity to run DC-capable computers, which some people consider more energy-efficient than using alternating current.
Server makers and data center operators are already circulating water to cool computing gear. Google's patent application envisions using the ocean to act as a giant heat sink, cooling computers through seawater-freshwater heat exchangers.
For the crew and operating staff, there could be living quarters and, potentially, a helipad to get there.
Seeking fortunes at sea
With the rising cost of electricity and concerns over the environment, getting cheaper and cleaner forms of electricity is a big concern for data center operators.
Google argues that floating data centers offer other advantages, such as placing computing closer to consumers, cutting down on transmission distances.
"Also, transient needs for computing power may arise in a particular area. For example, a military presence may be needed in an area, a natural disaster may bring a need for computing or telecommunication presence in an area until the natural infrastructure can be repaired or rebuilt," according to the patent application.
Google is not the only company to envision modular, container-based data centers or even floating data centers.
A San Francisco company, International Data Security (IDS), plans to pack discarded cargo ships with computing equipment.
The company intends to have its data center ships placed near urban centers and have one operating by the third quarter of this year.
According an IDS company blog, the primary motivation for IDS's floating data center is the higher cost of building a land-based facility, the resistance to earthquakes and other natural disasters, and the potential to tap water cooling.
"It seems (Google's) plan is slightly different than IDS; IDS floating data centers will be anchored in port the majority of the time, whereas Google's will be positioned out at sea," according to a company blog post on Saturday.
The financial model of operating a data center at sea may be the most clever aspect to the patent application, argues Larry Dignan, editor-in-chief at ZDNet. In theory, a floating data center would not have to pay any property taxes, he said.
Rich Miller at Data Center Knowledge said the Google plan could invoke different legal definitions of territory boundaries.
"The offshore location also raises interesting questions about jurisdiction, and which laws would govern the handling of any consumer data managed from the floating data centers. U.S. territorial waters typically extend 12 nautical miles, but other nations' claims range from 3 miles (Singapore) to 200 miles," he wrote.