Will SuperConductors SuperCharge Wind Turbines?
February 5, 2013
WIND turbines may soon get a supercharge. Turbines wound with superconducting wire instead of regular copper could turn today’s 2 to 3-megawatt generators into 10-megawatt powerhouses, say teams in Europe and the US that are racing to produce the machines.
At heart, a wind turbine is simple – a series of wire coils attached to the rotor blade spin in the presence of strong magnetic fields, provided by stationary magnets. This generates a current, but the resistance in copper wire limits the amount of current that can flow through the coils. Making the coils from a resistance-free superconductor would cut down on weight and boost power generation.
Using superconductors will not be easy, though, partly due to the ultra-low temperatures they require. Developing a coil that can be cooled while simultaneously rotating with the turbine blades is a big challenge. A research project dubbed Suprapower, funded by the European Union, kicked off in December to address this problem.
Holger Neumann at the Karlsruhe Institute of Technology in Germany and other members of the Suprapower consortium are betting on a new “high temperature” superconductor, magnesium diboride, which works at 20 kelvin. “It’s light, easily made into wires and is really cheap compared with the old niobium-titanium superconductors, which needed cooling way down to 4 kelvin,” Neumann says. That temperature difference might not sound much but it means, crucially, that cooling the magnesium diboride superconductor requires just one-seventh of the power.
The US team claims to be within a few years of building their own 10-megawatt wind turbine, and says that their techniques could make superconducting wires attractive for distributing electricity as well as generation.
“If we can demonstrate this superconducting-wire technology in a wind turbine, we think it’s more likely that it will make its way into the power cables of the electricity grid,” says Selvamanickam.