Using superconducting magnets could eliminate the need for rare earth materials in wind turbine generators and make for lighter more powerful machines
High field magnets used in MRI scanners that help doctors diagnose problems in the human body could help unlock the generation of more energy from offshore wind turbines, researchers at GE Research suggest.
In January 2021, a multi-disciplinary team of engineers at GE’s Research Lab in Niskayuna, New York was awarded US$20.3M in follow-on funding by the Department of Energy’s Wind Energy Technologies Office to accelerate the design and testing of a new superconducting wind generator.
The team at GE Research, which includes pioneers in scaling superconducting magnet technology for magnetic resonance imaging (MRI) scanners, is applying decades of experience to develop a more powerful generator for offshore wind turbines.
GE senior principal engineer and project leader for the superconducting generator project David Torrey says, “The industries and applications are vastly different, but the technical challenges and goals are very similar.
“With MRI, we have worked over many decades to increase the magnetic field of the superconducting magnets to deliver better image quality. In wind, we’re seeking to strengthen the magnetic field of the magnet to make generators that deliver more wind power with higher efficiency. With both applications, the goal is to enable these improvements while minimising their size and weight.”
“Can we pack more power in the same space with less weight?” Dr Torrey asks. “We’ve done this successfully with MRI systems time and time again. We think we can do it with wind power as well.”
In addition to increasing power while minimising the size and weight of generators, Dr Torrey notes that the use of superconducting magnets also would eliminate the need for rare earth materials, essential ingredients in the permanent magnets currently being used in offshore wind turbines. Today’s generators typically use about a tonne of permanent magnets for each megawatt of rating.
“Despite the vast differences between an MRI scanner and offshore wind turbine, the size and scale up required with the magnetic fields to support the offshore wind generator are not that different from what the team has experienced with MRI scanners,” says Dr Torrey.
Over many decades, GE Research’s MRI team has pioneered important advancements in superconducting magnets to strengthen their magnetic fields.
When medical professionals refer to MRI scanners, they sometimes say the scanner is a ‘1.5T’ or ‘3.0T’ scanner. This is because scanners are identified by their magnetic field strength. In terms of magnetic resonance, T stands for tesla, a unit of measurement. Tesla is the unit of measurement to define the magnetic flux density. With higher tesla scanners, the magnet is stronger, both in general and within the bore of the machine. The magnet and its magnetic field are arguably the most important aspects of an MRI scanner.
The first MRI systems introduced were in the order of 1.5T, but, over time, have increased in field strength to 3T while maintaining a comparable size and weight. GE researchers are currently developing a 7T head-only MRI system that would more than double the magnetic field strength, while containing the size and weight of the system.
The challenge of scaling up wind power is not dissimilar, GE says. With the generator, the key is delivering more power without increasing the size and weight of the generator itself.
The team believes it can apply the technical expertise and experience scaling MRI technology on the healthcare side to develop a superconducting generator that delivers more power with the same footprint to achieve higher annual energy production with reduced weight. This would help to drive down the levelised cost of energy from offshore wind.