Superconducting wind turbine generators

TLDR

The main challenge for superconducting direct‑drive wind turbines is demonstrating reliability superior to gearbox or permanent‑magnet alternatives. Future 8–10 MW offshore turbines are designed by up‑scaling a 5 MW model, and a staged testing strategy from 10 kW to 10 MW turbines is proposed to build reliability data. A 10 MW superconducting generator could supply 10 % of the EU offshore market by 2030, with the main advantage being the absence of a gearbox; however, achieving this requires 200–300 km of high‑temperature superconductor tape per turbine, demanding a 36‑fold increase in coated‑conductor production by 2020 to lower tape costs tenfold.

Abstract

We have examined the potential of 10 MW superconducting direct drive generators to enter the European offshore wind power market and estimated that the production of about 1200 superconducting turbines until 2030 would correspond to 10% of the EU offshore market. The expected properties of future offshore turbines of 8 and 10 MW have been determined from an up-scaling of an existing 5 MW turbine and the necessary properties of the superconducting drive train are discussed. We have found that the absence of the gear box is the main benefit and the reduced weight and size is secondary. However, the main challenge of the superconducting direct drive technology is to prove that the reliability is superior to the alternative drive trains based on gearboxes or permanent magnets. A strategy of successive testing of superconducting direct drive trains in real wind turbines of 10 kW, 100 kW, 1 MW and 10 MW is suggested to secure the accumulation of reliability experience. Finally, the quantities of high temperature superconducting tape needed for a 10 kW and an extreme high field 10 MW generator are found to be 7.5 km and 1500 km, respectively. A more realistic estimate is 200–300 km of tape per 10 MW generator and it is concluded that the present production capacity of coated conductors must be increased by a factor of 36 by 2020, resulting in a ten times lower price of the tape in order to reach a realistic price level for the superconducting drive train.