Why synchronous generator is used for producing electricity?

There are a few reasons why synchronous generator is used to supply power. There are

• Constant voltage 
• Constant frequency 
• Capability to deliver active as well as reactive power

• A synchronous generator is connected to infinite bus bar. Practically, more than two synchronous generator are connected in parallel with infinte bus bar. 
• During parallel operation of synchronous generator, appropriate synchronization of generators with bus bar is maintained.

Why not Induction generator?

If I.G is considered, then it arises two aspects

• Reactive power requirement for I.G
• Harmonic content in the output spectrum. 
• The output frequency of Induction Generator is variable which will create uncertainties in deciding ratings for electric equipment and load side equipment will have problems with variable frequency.
• To deal with this we need to convert variable AC power to DC power and back to fixed frequency AC power using power electronic equipment which induces high amount of harmonic content in output spectrum which is undesirable and design of harmonic filters and their implementation will increase cost.

Conclusion:

• Hence, synchronous generator is used for large production of electric power in thermal, nuclear, hydro, gas power plant etc.
• On the other hand, induction generator is especially used in wind power plant for production of electricity.