Researchers in the US have successfully completed full-power testing of the world`s first 36.5MW high-temperature superconductor (HTS) ship propulsion motor. The tests, performed at a US Navy site in Philadelphia, are the first to be conducted on a commercial-scale HTS motor.

The test motor was designed and built by American Superconductor (AMSC) and Northrop Grumman under a contract from the US Office of Naval Research intended to demonstrate HTS motors that could be used to propel future all-electric ships and submarines.

The motor incorporates coils of HTS wire that can carry 150 times more current than similar-sized copper wires. It is less than half the size and weight of a conventional motor and could reduce ship weights by nearly 200 tonnes, making them more fuel-efficient and freeing up space on board. It is also quieter then conventional propulsion systems. The illustration above shows the relative sizes of conventional (left) and HTS motors with a similar output.

“The successful load test of our HTS motor marks the beginning of a new era in ship propulsion technology,” declares AMSC senior vice-president, Dan McGahn. “This motor provides the US Navy with a truly transformational capability relative to size, stealth, endurance and survivability, providing our Navy with a clear performance advantage for years to come."

The US Navy has invested more than $100m in HTS technology, paving the way not only for using the technology in its own ships but also in commercial vessels such as cruise liners and tankers. Last year, the Navy installed an HTS degaussing coil on one of its vessels and this will undergo sea trials over the next two years.

HTS rotating machine technology is also being applied in the renewable energy industry. Wind generator systems using HTS wire instead of copper are expected to be much smaller, lighter and more efficient than current systems.

Now that the testing is complete, the HTS motors are ready for deployment. The US Navy currently has budget constraints, but an AMSC spokesman says that it working to identify the first surface ship or submarine for its HTS motors.  It is also seeking partnerships with motor manufacturers to commercialise the technology.