Drogue plans floating data centres run on ocean thermal energy, TechCrunch reports

TechCrunch's Tim De Chant reported on 13 November that Drogue, a Washington, D.C. startup founded six months ago, is developing technology that turns ocean heat into electricity for data centres aboard floating vessels. Drogue's founder and chief executive, Sam Sipe, spent years flying E-2D Hawkeye aircraft from US Navy carriers, the report says.

The method is ocean thermal energy conversion (OTEC), which originated in the 1950s and makes electricity from the temperature gap between sun-warmed surface water and cold deep water, TechCrunch says. In Drogue's design, warm water taken in at the surface first cools the servers; the heated water then boils ammonia, and the ammonia vapour drives a turbine. A condenser turns the vapour back to liquid, its fins chilled by water drawn up from 1,000 metres down, and that water, now warmer, is let out into the sea while the ammonia circulates again in a closed loop. Deep ocean water averages about 4°C, according to the report.

TechCrunch says the approach was trialled in the 1980s and later abandoned. Sipe says manufacturing methods for its pipes and heat exchangers have changed a great deal since then, and that people who worked on those early projects told him the technology works, the obstacle being to raise enough money for a plant of sufficient size.

Carrying the power to shore would need long, costly cables, TechCrunch says, whereas data centres suit a floating plant because servers are compact and sending data off the platform costs very little. Drogue has already drawn up the design for a prototype of several megawatts, to be fitted to a conventional oceangoing ship and go to sea early in 2028, according to the report, and later versions would sit on floating structures closer in form to offshore oil platforms. Sipe says each vessel would remain at sea for about ten years. The American Bureau of Shipping, which sets ship safety standards and checks that they are met, has given Drogue an approval in principle, an early-stage endorsement, TechCrunch reports, and the company is now purchasing its first vessel so it can begin building the prototype.

Sipe told TechCrunch the aim is to let data centre developers add servers on timelines that suit AI. He says the data centre industry works as a real estate business on timelines of 8 to 10 years, counting dealings with utilities and grid operators, while AI demand has risen tenfold in the past three years. TechCrunch notes that the oceans take up 5.8 million terawatt-hours more energy each year as the planet warms, against roughly 180,000 terawatt-hours used by all of humanity.

Drogue told TechCrunch it has raised $20 million from investors including XYZ Venture Capital, Toyota Ventures, Tamarack Global, Dream, FDVC, Garuda Ventures, Flexcap, Boost VC and Slow Ventures.