A European Union cryogenic* wind project called SUPRAPOWER aims to facilitate the development of more compact, reliable, and powerful wind turbines by using smaller, and lighter generators that can generate just as much power as bigger, traditional generators.
This would be achieved by cooling the wind turbine’s generator coils to cryogenic temperatures until they reach a superconductive state.
At this state, the resistance of the coils to the flow of electric current is zero, so the coils don’t generate heat.
The reason this makes it possible to use smaller generators is because their power handling capacity is actually determined primarily by their temperature. More current translates into generation of more heat, and the generators can only handle so much heat.
Once they get too hot, you can’t let them generate any more current because they will overheat. This amazing phenomenon is called superconductivity, and the coil becomes a superconductor.
In the case of this project, a rotating “cryostat” is the device used to cool the generator down to -253.15°C by means of small Gifford-McMahon coolers provided by the project partner Oerlikon Leybold Vacuum.
A cryostat is a device into which you put objects to keep them refrigerated.
Reliability Benefits of Superconductors
Heat is what destroys generator coils, and nothing else. Keeping them cool enables them to last decades. All wind turbines could benefit from this, but offshore wind turbines could particularly benefit from reduced maintenance requirements.
Efficiency Benefits of Superconductors
In addition to the above, superconducting coils do not waste as much electricity as heat because they don’t resist the flow of electric current. This improves wind turbine efficiency in this case.
Performance Benefits of Superconductors
Superconducting wires are smaller because they can handle unusually large amounts of electricity. This is because they don’t get hot, due to a lack of electrical resistance.
Superconducting refrigerators do come at a cost. However, they are promising and this effort may succeed. And if it doesn’t, as usual, researchers will learn from it, which will help to advance the science of wind-related research.
*If a substance is cryogenic, that means its temperature is below -150°C.