What’s claimed as the world’s first test of high-temperature superconducting technology in a grid-connected utility-scale wind turbine has been hailed by a team led by Envision Energy as a big step towards future supersized machines.
The Chinese wind group led the EU-backed EcoSwing project, which said it now hopes HTS drive-trains can emerge as viable competitors to the permanent-magnet direct-drive (PMDD) technology used by turbine OEMs.
EcoSwing tested an HTS-equipped generator in a 3.6MW Envision GC-1 turbine operating in Thyborøn, in western Denmark, replacing its standard PMDD unit.
The turbine met its goals of operating in a power range above 3MW and ran for about 650 hours of grid-connected operation, said a final report on the project, which wrapped up in May but has just published its findings in a journal of the Institute of Physics.
The superconducting rotor coils showed “great performance and reliability” during “more than seven months of stable and reliable cryogenic system operation”, said the project team. Many Danish homes can now claim to have been “powered by superconductivity”, it added.
The development of HTS technology is claimed as a key enabler of future direct-drive machines that use lighter, more compact components, and rely less on expensive and sometimes hard-to-source rare earth materials than current PMDD systems. The world’s current largest wind turbine heading for commercial deployment, the 12MW Haliade-X from GE, uses a permanent magnet generator.
The project team said the Danish test had shown the potential for HTS to reduce generator weight by 40%.
“Wind turbine size has grown significantly over recent decades. However, today’s technology has trouble keeping up with this trend towards ever increasing unit power levels,” said project member Anne Bergen of the Netherlands' University of Twente in the published findings.
“The feasibility of 10+ MW PMDD turbines requires significant weight reduction.”
Bergen added that the Danish test showed “the compatibility of superconductive generator technology with all the real impacts present in an operational environment such as variable speeds, grid faults, electromagnetic harmonics, vibrations etc.”
Recharge has reported extensively over the last decade on efforts to harness the benefits of HTS technology for future turbines that are expected to reach ratings as high as 20MW.
Most recently, the US Department of Energy announced backing for American technology specialist AMSC in work to use HTS materials to replace permanent magnets in the generator rotor, potentially reducing size and weight by 50%.