The European EcoSwing project swapped a compact and lightweight electric superconducting generator for a conventional generator in a 3.6 Megawatt wind turbine.

The new generator is 4 meters in diameter, 1.5 meters smaller than a conventional one. It sits inside an 88 meter tall 3.6MW turbine in Thyboron, Denmark.

The magnets made from a composite tape with a ceramic superconducting layer: gadolinium–barium–copper oxide (GdBaCuO). The superconducting layer sits on a steel ribbon for flexibility and strength.

The superconducting tape is protected from metal poisoning by layers of magnesium oxide and silver. The magnesium oxide also acts as a template for the precise crystalline structure needed by the GdBaCuO. An outer copper layer offers electrical and thermal stabilization. Tens of kilometers of this tape sits inside the new wind turbine.

A conventional wind generator making 1MW of power will have about one tonne of neodymium in its magnets. The superconductor uses about 1 kilogram of the rare earth gadolinium. It costs just $18.70/kg (£14.50/kg) of gadolinium oxide versus $45.50/kg of neodymium oxide.

There have been supply issues for the neodymium. China has most of the rare earth supplies.

Off-the-shelf cryo-coolers from SHI Cryogenics in the UK chill the superconductor to –240°C.