Induction generator systems are typically used to generate the bulk of an industrial facilities electrical load during peak rate periods. This is referred to as peak shaving or base load displacement. The parallel nature of induction generator systems is that they require an excitation drawn from an available utility power source. In other words, induction generator systems cannot produce power without an operational source of utility power. Induction generator systems are more expensive than synchronous generators because of the controls and automatic switching required for parallel operation.
Synchronous units provide backup and independence.
Induction units provide peak shaving. Generator Sizing Synchronous generators need to be properly sized. One important factor in properly sizing a generator system is determining surge loads. Peak load demands occur when large electrical motors are in the process of starting up. When electrical motors start they can draw a momentary surge demand that is five times larger than their normal operating demand.