GE Researchers Developing New Generator for Wind Turbines Up to 15MW

GE Global Research, General Electric’s technology development arm, announced it has begun work on the first phase of a 2-year, $3 million project from the US Department of Energy to develop a next generation wind turbine generator that could support large-scale wind applications in the 10 MW to 15MW range.

The generator is the part of a wind turbine that converts mechanical energy generated by the turning blades into usable electrical power. How effective a generator is directly impacts how much wind is converted into electric power.

Currently, most wind turbines have conventional generators that are connected to a gearbox. The gearbox is used to step up lower blade speeds into higher speeds. While extremely effective in wind turbines up to about 3.5 MW in size, the same technolgoy used in larger turbines would increase weight, maintenance and overall costs significantly.

"With the industry’s desire for higher megawatt machines to maximize 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, GE Global Research. "The key challenge will be delivering solutions that achieve the right scale and cost."

Longtin says 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.

GE’s superconducting machine design will employ a cryogenic cooling technology that is expected to improve the reliability of the complete machine. GE’s proposed superconducting machine aims to have twice the torque density of competing technologies and will additionally 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.

The generator project will have two phases. Phase I will focus on developing a conceptual design and evaluating the economic, environmental, and commercial factors associated with it. Phase II will explore the potential commercialization of the technology.

The Oak Ridge National Lab (ORNL) will be a key partner with GE on the generator project, helping GE to investigate and mitigate high-risk technology challenges associated with the project.

In addition to the next generation wind turbine generator project, GE researchers are expoloring other technologies that will enable the economic scale-up of wind, including:

• Lighter, more advanced composite materials to enable longer wind blades that enhance wind capture without adding so much weight that it increases the cost of power
• Advanced controls, sensors and condition monitoring algorithms to dramatically reduce operating costs
• Grid integration technologies to seamlessly integrate larger amounts of wind into the grid.