Lightweight generator a world first for emergency power

19 April 2006

A ground-breaking lightweight and portable generator - the first in the world to use high-temperature superconductors - could offer huge advantages for emergency power supply.

Featured at Superconducting City at this year s Hanover Fair, the generator is being developed in a partnership between US-based Long Electromagnetics Incorporated (LEI), and HTS-110 Ltd from New Zealand.

HTS-110' s technical director, Mike Fee, said that while a conventional 5MW generator weighs five tonnes alone, the new generator combined with a gas turbine and associated power electronics package will have a total weight of less than 1.5 tonnes (1500kg).

It will have a footprint small enough to install the entire system within a single shipping container, or on a small truck, and will be a compact, rapidly deployable power supply.

It could be moved easily by plane, helicopter, or ground transport anywhere that remote or emergency power is required, such as for disaster relief or short term industrial power usage.

Five megawatts is sufficient to power around 2500 average homes. LEI has designed and built a prototype generator, which will be tested within the next six months. It is anticipated the generator will be on the market within two years. LEI managing director, Larry Long, said the operational challenges of building superconducting generators are similar to those of Formula One racing cars.

Both machines operate in a very demanding environment where every component is pushed to its absolute limit. But there is huge potential for high payoffs and the development of this high-speed generator opens up tremendous opportunities in applications where size and weight are important.

The generator consists of a four-pole superconducting rotor, wound with BSCCO superconducting wire, and a conventional oil-cooled copper stator.

The high current density achievable with superconducting rotor windings produces a high magnetic field in a very compact rotor.
In combination with a 12,000-15,000 rpm operation, four to five times faster than conventional machines, this results in an extremely lightweight and portable generation system for the designed 5 MW output power.

The high-speed operation means the generator can be driven directly from a turbine, meaning there is no need for a gearbox and significantly reducing weight and maintenance requirements.

The operating temperature of the rotor is around minus 240 C. Even including the power consumption of the cryogenic cooling system, the generator efficiency is at least as good as that of a conventional machine.

Background:
High temperature superconductors are ceramics that can conduct very large electrical currents with extremely low resistance when cooled to around the temperature of liquid nitrogen (-196 C).

HTS-110 Ltd is an affiliated company of Industrial Research Ltd, which holds a key patent for BSCCO, the ceramic used in first generation high temperature superconducting wire. Superconductors are far more efficient at carrying electricity than copper. A superconducting wire can carry more than 100 times the current of a copper wire of similar cross section.

LEI is a United States-based company which designs and manufactures conventional and superconducting generators and power system equipment for specialised commercial and military applications. LEI is presently fabricating several multi-megawatt superconducting generators for the United States airforce, NASA and commercial power systems.