about turbine based power plants (coal, gas, nuclear)
they waste about 50% of their fuel. the problem with isn't the generator itself, which can be close to 99% efficient for large generators. the losses happen as the steam is turned into torque by the turbine that drives the generator's shaft.
i used to think nuclear power plants had some kind technology in them that extracted energy from the radiation directly. i had no idea they were just giant steam engines. i thought the Steam Age had ended.