A robotic underwater vehicle powered by ocean movement

A robotic underwater vehicle that is powered entirely by natural, renewable, ocean thermal energy has been developed, holding out promise of almost indefinite monitoring of the ocean depths for climate and marine life studies.

Researchers have successfully demonstrated the Sounding Oceanographic Lagrangrian Observer Thermal RECharging (SOLO-TREC) autonomous underwater vehicle that uses a novel thermal recharging engine, powered by the natural temperature differences found at different ocean depths.

Scalable for use on most robotic oceanographic vehicles, this technology breakthrough could usher in a new generation of autonomous underwater vehicles.

A map of Solo-Trec's three-month journey off the Hawaiian coast.
(Credit: NASA/JPL/SIO/NOAA/U.S. Navy/NGA/GEBCO/Google)

Researchers at NASA's Jet Propulsion Lab (JPL), Pasadena, California and the Scripps Institution of Oceanography, University of California, San Diego, completed the first three months of an ocean endurance test of the prototype vehicle off the coast of Hawaii in March.

"People have long dreamed of a machine that produces more energy than it consumes and runs indefinitely," said Jack Jones, a JPL principal engineer and SOLO-TREC co-principal investigator.

"While not a true perpetual motion machine, since we actually consume some environmental energy, the prototype system demonstrated by JPL and its partners can continuously monitor the ocean without a limit on its lifetime imposed by energy supply," added Jones.

"Most of Earth is covered by ocean, yet we know less about the ocean than we do about the surface of some planets," said Yi Chao, JPL principal scientist and SOLO-TREC principal investigator.

"This technology to harvest energy from the ocean will have huge implications for how we can measure and monitor the ocean and its influence on climate," Chao added, according to a JPL release.

So far, SOLO-TREC has completed more than 300 dives from the ocean surface to a depth of 500 meters (1,640 feet). Its demonstration culminates five years of research and technology development by JPL and Scripps and is funded by the Office of Naval Research.