Hybrid Power systems integrate different types of energy sources such as renewable energy sources, conventional fuel operated electric generators with some electrical energy storage systems. Hybrid Power systems can be used on-grid, off-grid, and in custom mode for a specific purpose. A Hybrid Power System makes use of Solar, Wind, Fuel based Generator and battery storage in an integrated manner and offers redundancy along with many advantages over conventional single power source.
For a given geographical region, availability and functional parameters of renewable energy sources such as wind speeds, sun light and water flow are not constant during the day or year.
During summer, sun light is intense and longest, but wind speed is very low.
Where as in winter, the sun light is available less and for shorter time but the wind speed is strong. Because the peak operating times for wind and solar systems occur at different times of the day and year, hybrid systems are more likely to produce power when you need it.
Many hybrid systems are stand-alone systems, which operate "off-grid" -- not connected to an electricity distribution system. For the times when neither the wind nor the solar system are producing, most hybrid systems provide power through batteries and/or an engine generator powered by conventional fuels, such as diesel. If the batteries run low, the engine generator can provide power and recharge the batteries.
Adding an engine generator makes the system more perfect but bit complex, but electronic controllers and converters can run these systems automatically. An engine generator can also reduce the size of the other components needed for the system. Keep in mind that the storage capacity must be large enough to supply electrical needs during non-charging periods. The size of Battery banks is depend on the electric load for one to three days.