Design

High-temperature superconductors
Superconductors are materials that lose their electrical resistance when cooled below a certain critical temperature, but the high-temperature variety (HTS) – which operate at more manageable temperatures – have been developed since the late 1980s.
The materials can carry more than 100 times the electrical current than standard copper wire of the same dimensions, but has been seen as an expensive option compared to conventional wire.
AMSC now mass produces HTS wire at its Massachusetts headquarters, claiming that the wire can carry 150 times the electrical current of copper wire, "dramatically" reducing the size and weight of electrical equipment and "significantly" increasing the throughput of power cables.
The firm is now working on a "second generation" HTS wire, which it believes will see manufacturing costs five times lower than its first generation product.
At the same time as the cost analysis work, AMSC is continuing to work with Texas-based electric motor specialists TECO-Westinghouse Motor Company to develop superconductor technology for 10MW-class wind generators.
The $6.8 million (£4.7 million) design project has been going on since late 2007, 50% funded by the National Institute of Science and Technology's (NIST) Advanced Technology Program.
"Active dialogue" is already underway with partners regarding the kind of towers, blades and other components that will be required to host such large turbines, Mr Fredette said.
Once complete, the two feasibility projects will feed into work to build and test a full-size prototype superconductor wind turbine, before the 10MW system is made commercially available in the middle of the next decade.
Wind turbines have been getting steadily larger, particularly for offshore deployment. AMSC said it believed the limitations of conventional technology meant turbines would top out at about 6MW in scale.
Fellow US company Clipper is currently working on a 7.5MW offshore wind turbine, with the intention of developing a prototype in North East England, as well as a new production facility in the east of Newcastle.
AMSC's business model is to licence out its wind turbine designs to customer companies and provide the superconductor components, rather than make the wind turbines themselves. It also helps customers set up supply chains to source all the required components.
It has existing customers producing 1.65MW and 2MW turbines in eastern Europe and the Far East - where China's biggest wind turbine company Sinovel is about to start production on a 5MW model later this year. These would be "logical" partners for the 10MW model, the firm said.
But, Mr Fredette said AMSC hoped to find a partner in the UK or northern Europe to supply the 10MW turbine for the UK market.