Which requires less energy to produce electricity, a Synchronous or Asynchronous generator?

A permanent magnet generator can be a little more efficient than an induction generator of equal power rating and quality. The permanent magnet synchronous generator will have very low rotor losses. The stator and mechanical losses will be about the same in both motors.

in basic terms like the final responder mentioned, it relies upon on many variables. you may desire to be conversing approximately an alternator (generator on your vehicle), a small residing house generator, or a generator related to a nuclear skill plant! All 3 of those are going to offer diverse quantities of skill at diverse RPMs. no longer the terrific analogy, yet what if I asked you the way quickly a airplane might desire to fly whilst its propeller grow to be spinning at x RPM ? relies upon on lots greater suitable than the angular velocity!

There is no inherent reason why one type of generator will be more efficient than the other.