GE Global Research says it has begun work on the first phase of a two-year, $3 million project from the U.S. Department of Energy to develop a wind turbine generator that could support large-scale wind applications in the 10 MW to 15 MW range.
Most wind turbines have conventional generators that are connected to a gearbox, which is used to step up lower blade speeds into higher speeds. According to GE Global Research, this method is effective, but will become more costly as developers scale up to larger wind platforms, due to the required additional weight and maintenance needs.
‘With the industry's desire for higher-megawatt machines to maximize clean wind power opportunities in the U.S. and around the globe, new technologies will be needed to support larger-scale wind platforms,’ says Keith Longtin, wind technology leader at GE Global Research. "The key challenge will be delivering solutions that achieve the right scale and cost."
Longtin adds that the application of superconducting technology could enable significant improvements to the generator and make the elimination of the gearbox more economical.
The keys are reducing the size and weight of the generator while reducing speed and increasing torque. Utilizing superconducting technology reduces weight by virtue of the high magnetic fields that can be created by the superconducting field winding and the fact that the heavy iron in the superconducting generator can be reduced, he explains.
GE's superconducting machine design will employ a cryogenic cooling technology, which the company says will result in an improvement in reliability of the complete machine. GE's proposed superconducting machine aims to have twice the torque density of competing technologies and reduce the dependence on the rare-earth materials prevalent in all permanent magnet machines for wind.
The larger power levels of these machines, coupled with their improved energy-conversion efficiency, leads to more favorable economies of scale (e.g., fewer towers for a given wind-farm output) that will help reduce the cost of energy produced by wind turbines, GE adds.