Large scale superconducting wind turbine cooling

General Electric proposes to apply transformational technology in the form of low-temperature superconductivity to the design of direct-drive wind turbine generators of the 10-MW power level and greater. Generally, optimal steady state 4 K cryogenic cooling of a large thermal mass ( > 10 000 kg) and its dimensions (> 4 m diameter and 2.5 m length) with minimum levelized cost of energy is difficult to achieve. A cooling strategy has been found that turns this size disadvantage to ones favor, and furthermore enables the design scalability of the field winding cooling assembly towards 15 to 20 MW. In this design study, we show that size and efficiency are not mutually exclusive and that it is indeed possible to minimize cryogenic complexity and reduce cost. The cryogenic push-button closed loop circulating system is invisible within the nacelle of a wind turbine and requires no handling of cryogenic liquids. Besides the occasional cryocooler service requirement, the proposed solution is maintenance-free in all operating states and allows the system health to be monitored remotely. The design solutions proposed could potentially make large superconducting generators a reality for off-shore wind turbine deployment.