A 250’ barge being converted in Vallejo, Calif., is the first working vessel with a concept proposed by Google engineers years ago: a floating data center that cuts down on big energy costs by using the water around it for cooliing.

Cooling costs are a big factor in running data centers, with power required for pumps and heat exchangers – and in drought-ridden California, increasingly scarce fresh water. Floating data centers would use the enormous heat exchange potential of water around their hulls.

The startup company Nautilus Data Technologies, Pleasanton, Calif., says it proofed the concept earlier this year, with validation by engineering firms Jacobs Engineering Group, Pasadena, Calif., and Critical Engineering Group, Orinda, Calif., specialists in designing critical infrastructure. The challenge is not so much technical, as assuring would-be customers a data center vessel is prudent, but backers contend the mobile floating design is actually more survivable, and can even serve in disaster recovery missions.

Nautilus CEO and co-founder Arnold Magcale was an early adapter of “cloud computing,” and before his technology career served for a decade in the U.S. Navy special forces. From an early idea of using surplus military vessels, the company came up with a business model using “ocean-worthy barges that meet all Coast Guard certifications and exceed international maritime standards.”

The barges are upgraded former military or construction vessels that have a 40- to 50-year extended life, according to Nautilus. The company will build high-density data centers, with space for up to 800 server racks and 8 MW capacity, ready for delivery and deployment in less than six months worldwide.

Operating expenses for a data center that size can be cut 50% by the company’s cooling system, which recycles all onboard fresh water for cooling through heat exchange with water outside the hull. With intelligent power management and other technology developed by Nautilus that can be a savings of up to $4 million annually, the company predicts. Traditional on-land data centers face escalating energy costs and are already bumped up against the limits of power use effectiveness (PUE) cost.

Modular design can adapt the barges in different configurations – the first vessel built at the Mare Island Naval Shipyard at Vallejo has four 2 MW data halls. The company says short turnaround times for construction and the ease of waterfront location in sheltered waters is a much faster solution for customers than land-based construction. The first barge is on track for completion and deployment to a secure waterfront location late this year.