Rare earth materials are sometimes used to manufacture permanent magnets (which are most commonly known as “magnets”, which is vague). Permanent magnets are sometimes used in electric motors and alternators (which are just generators that generate alternating current), but some have raised awareness of a shortfall in the supply of the materials required to manufacture these magnets.
Some of these materials come from China, and they produce almost 95% of the world’s rare earth materials. China is expected to cut the exportation of these materials apparently due to impending shortages. This article pertains to the importance of rare earth magnets to wind turbines, electric vehicles, and other types of generators. Some have stated that rare earth magnet shortages would limit the production of electric vehicles and wind turbines as if they require them.
First of all, almost all power plants and combustion engine powered vehicles, including gasoline, natural gas, nuclear, coal, and diesel require alternators and dynamos (DC generators) as do wind turbines. This is because these power plants are mechanical. All alternators operate on the principle of electromagnetic induction to generate electricity using a magnetic field. So if this was an issue for wind turbines and electric vehicles, it would also be just as much an issue for fossil fueled power plants and vehicles because they require generators too.
Secondly: Induction motors and generators are actually the most common.
Induction generators and motors do not require any permanent/rare earth magnets because they utilize copper coils as electromagnets. Electromagnets are coils of wire that are supplied with electricity which then creates a magnetic field. [Source: Northeastern University]