You need them for solar inverters, but you also need them for the turbines like those used to generate power with geothermal/wind/hydro/nuclear/etc.
You need them for solar inverters, but you also need them for the turbines like those used to generate power with geothermal/wind/hydro/nuclear/etc.
Erbium perhaps for some power semiconductors, but in very small amounts.
What's the use in turbines? Most generators associated with turbines don't use permanent magnets.