The Plan to Build a Global Network of Floating Power Stations | WIRED
https://www.wired.com/story/the-plan-to-build-a-global-network-of-floating-power-stations/
From the outside, Seatrec’s ocean thermal generator doesn’t look like much. The SL1 is about as tall as a person, 6 inches wide, and has a smooth, nearly featureless black and gray exterior. But it’s what’s inside that counts. The bottom of the cylinder is packed with a specially designed wax that changes its phase depending on the temperature. The wax solidifies when the SL1 lowers itself into the frigid depths of the deep ocean. Then, when the tube resurfaces, the relatively warm water causes its waxy innards to liquify. During the phase change from solid to liquid, the wax increases in volume and raises the pressure inside the tube, which forces a fluid through a generator and creates electricity. All the device has to do to recharge is descend into colder water to resolidify the wax; it can do this by releasing a tether or deflating an internal air bladder.
Over the course of three weeks last February, Chao and his team sent two of the company’s generators on several dives to 3,000 feet beneath the surface while attached to a profiling float. It was only the third time that an SL1 had ever been deployed in the ocean, and the submersible generators were going hundreds of feet deeper than they had on previous dives. Yet they still managed to generate enough energy to power many types of research tools deployed by oceanographers. It was an unambiguous success.
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Chao hopes that Seatrec’s ocean generator will deliver on a promise first conceptualized in the 1980s by the renowned oceanographers Douglas Webb and Henry Stommel. They envisioned a globe-spanning fleet of missile-shaped underwater research robots called Slocum gliders that would explore the oceans with the same dexterity, autonomy, and longevity that we’ve come to expect from the robots that NASA sends to explore other planets. Like Seatrec’s SL1, these gliders would be powered by underwater temperature differences
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Tapping the ocean’s natural temperature differences to create clean energy has promise, but Seatrec has a lot of work to do before its technology sees widespread commercial use. As Jayne points out, oceanographers are generally reluctant to adopt new technologies until they’ve been thoroughly tested. The last thing any scientist wants is to deploy a fleet of research vehicles only to have them fail a year into their mission. But Chao is confident that ocean thermal energy is the future.
“My vision is millions of robots at sea,” he says. “By the end of the decade, I think we are going to get three-dimensional oceanographic data in real time and we’re going to power the blue economy.”