In a startling new take on data center engineering, Google has filed a patent for a "water-based data center" that uses the ocean to provide power and cooling. The patent also confirms Google's development of a container-based data center, describing "crane-removable modules" to power the computing platforms.

The floating data centers would be located 3 to 7 miles from shore, in 50 to 70 meters of water. If perfected, this approach could be used to build 40 megawatt data centers that don't require real estate or property taxes.

The patent application, which was filed in Feb. 2007, was noticed by TheODP, who posted details to Slashdot. That suggests that Google's plans for floating data centers may predate a similar proposal from San Francisco startup International Data Security (IDS) to build data centers on cargo ships.

The Google design incoporates the Pelamis Wave Energy Converter units, which use the motion of ocean surface waves to create electricity and can be combined to form "wave farms." The largest existing project uses seven Pelamis units to generate about 5 megawatts of power. Diagrams included with Google's patent application indicate the company plans to combine 40 or more Pelamis units to produce 40 megawatts of power.



The patent documents describe a cooling system based on sea-powered pumps and seawater-to-freshwater heat exchangers.

Google previously was granted a patent for a portable data center inside a shipping container, which the company began developing in 2003, well before Sun Microsystems and other competitors began unveiling products based on the "data center in a box" concept. One of the inventors listed on the Google patent, William Whitted, later said the portable data center project had been discontinued.

Back in April we asked Google about the status of its container research. "We do a lot to make our infrastructure scalable and cost efficient, but at this time we have nothing to announce regarding this specific technology,” a company spokesperson said. But the patent filing describes the use of shipping containers in the sea-going data center:

The data centers may be employed with the computers inside standard shipping containers to make them more portable (e.g., capable of being hauled to the boat or by a truck). The data centers may be constructed modularly in areas having low costs, and may be transported to locations needing communications support relatively quickly. The data centers may be offloaded to areas where a more permanent presence is needed, and may also be connected to the motion-powered machines after such offloading, freeing the ship to deploy to another area. Also, data centers, when in the form of shipping containers, may be quickly traded out when technology changes. Modularization also makes maintenance simpler; hardware that is corroded or worn out from the harsh salt water environment can be easily replaced with fresh hardware by swapping containers

Google says the data center containers could be stacked two or more high, so that each data barge could hold "12 or more" containers.

The patent filing says the data centers would be located 3 to 7 miles offshore, which may signal that Google's interest in undersea cables goes beyond connectivity between land-based data centers. While the floating data centers would include power and cooling, they would still require industrial strength connectivity. Earlier this year Google said it would partner with five other companies in building an undersea communications cable across the Pacific, which could provide high-speed connectivity to new Google data centers in Asia.

Google said it would use signaling mechanisms such as strobing lights, flags, and horns to alert other ships of the existence and location of its data centers.

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 .

The offshore location also differentiates Google's plans from those announced by IDS, which plans to build up to 50 data centers on de-commissioned cargo ships moored at piers in major cities.