Why sine wave is used for power supply systems globally?

AC power comes from an electrical generator, which is a set of stationary coils (the stator) around a rotating magnetic field (the rotor). This configuration produces a sine wave output. We use a sine wave on the power grid because that's the way the electricity is generated, and it is a "natural" thing to do.

•  It's a "pain" to have to convert it to another wave shape.
•  There is also the fact that some nasty harmonics will appear on the power grid if we try to use triangular or square waves. Particularly with a square wave.
•  The electrical loss will be higher, too.
• Additionally, the sine wave is the 'purest' waveform, being the root of all other period wave forms.

THE MAIN FACT IS THAT-SINE WAVE GENERATES LEAST HARMONICS COMPARED TO SQUARE, TRIANGULAR ETC. AND THE REMOVAL OF HARMONICSIS NOT SO COMPLICATED FOR SINE WAVE.