SPOTLIGHT: American Superconductor Corporation

Sea Power: American Superconductor Corporation (AMSC) is developing, for the Office of Naval Research [ONR], the first high-temperature superconductor (HTS) motor for ship propulsion. Please tell us about this technology--and about HTS motor development.

YUREK: For the past 15 years, AMSC has been developing wires from HTS materials, and we are now manufacturing them in the world's first high-volume HTS wire- manufacturing plant, in Devens, Mass. When cooled to cryogenic temperatures, HTS wires can conduct more than 140 times the electricity of copper wires of the same dimensions. This enables us to develop motors and other systems that have significantly higher electrical efficiency and greater power density.

The 5MW-230rpm HTS ship-propulsion motor we have built and are currently testing for the Navy is half the size and weight of a conventional motor of the same power and torque rating. This motor has undergone successful no-load factory testing and is now being prepared for full-load testing with a power electronic drive. It is on schedule for delivery to the Navy in July 2003.

We also recently won a contract from ONR to develop, manufacture, and factory-test a 36.5MW-120 rpm HTS ship-propulsion motor. The torque of this motor is 10 times that of the 5MW motor. It will be half the size and one-third the weight of a copper-based motor.

Because both the 5MW and 36.5MW motors are suitable for electric warships as well as commercial cruise and cargo ships--which have largely transitioned to electric drive--we are on track to develop a new industrial base for ship-propulsion motors and generators in the United States.

Won't these HTS motors and generators be more expensive than conventional machines? What advantages do they offer?

YUREK: Because of the huge reductions in size and weight, we expect the price of HTS ship-propulsion motors to be equivalent to the price of conventional motors. They will have higher net efficiency, compared with other motors and generators, which means lower operating costs. We estimate, for example, that a U.S. Navy DDG-51 [Arleigh Burke-class guided-missile destroyer], electrically powered by an HTS propulsion system, would save approximately $450,000 per ship per year in fuel costs. The reductions in size and weight also provide the opportunity to create new ship designs that will have advantages with respect to speed, maneuverability, and space for munitions and crews quarters.

It would seem that the advantages of HTS technology could have broader benefit to the Navy--could you please give us your views on that?

YUREK: The implications for the Navy and the military in general are significant. Admiral Cohen [Rear Adm. Jay M. Cohen, chief of naval research] has stated that the future of naval warfare will include all electric ships and many electrically intensive applications, including advanced high-power multifunction radar, high-power microwave, electric rail guns, and high-energy lethal lasers, as well as the capability for electromagnetic launch and recovery of advanced aircraft. All of these applications will benefit from high-power-density, high-efficiency HTS technology.

What naval ships now under development are candidates for the installation of HTS motors?

YUREK: Our HTS motors and generators will be ready for the first electrically propelled warships, including the next-generation surface combatant, or DD(X), and the littoral combat ship. In addition, we will be able to provide for the needs of electric drive on submarines in the future. We are targeting commercial sales of 5MW-class HTS motors for 2005, which will continue to build the industrial base to meet future Navy needs.
Is your company currently allied with any shipbuilders in your Navy development programs?

YUREK: We initiated a close working relationship with Northrop Grumman several years ago. Through this relationship, we gained valuable insight into ship and propulsion system integration issues, and Northrop Grumman has gained insights into opportunities for new ship designs.

Late last year you estimated that the global market for electric ship propulsion motors and generators will grow from $400 million per year to $2 billion per year in the next 10 years. What is the future outlook for electric drive in naval and commercial applications?

YUREK: Despite the worldwide reduction in commercial shipbuilding, the growth of electrically propelled ships has continued. While the first commercial ships to become electrically propelled included cruise ships, cable layers, research ships, and icebreakers, we are now seeing orders for the first electrically propelled RO/RO [roll-on/roll-off ships], RO/PAX,(roll-on/roll-off/passenger ships) product tankers, and LNG [liquified natural gas] ships. Fourteen navies of the world either are building or designing electrically propelled ships.

The commercialization of HTS marine propulsion motors, which we project to occur in the 2004-2005 timeframe, will accelerate the growth of electric propulsion systems because of their significant advantages.

Other than the HTS motors and generators, and their future derivatives, do you have other naval or maritime products under development or in production?

YUREK: We've received inquiries concerning HTS cables for power and degaussing applications, as well as HTS transformers for the Navy's future electric ships. We're also working on another ONR program to develop a series of power-dense power electronic modules as part of the Power Electronic Building Block, or PEBB, program. We look forward to pursuing these further. Also, we may initiate other application-specific product developments in the future. *