Definition of Hybrid Power Systems:
 

Hybrid power systems are designed for the generation and use of electrical power. They are independent of a large, centralized electricity grid and incorporate more than one type of power source. They may range in size from relatively large island grids of many megawatts to individual household power supplies on the order of one kilowatt.

Hybrid power systems that deliver alternating current of fixed frequency are an emerging technology for supplying electric power in remote locations. They can take advantage of the ease of transforming the AC power to higher voltages to minimize power loss in transferring the power over relatively long distances. Isolated AC systems include at least the following: conventional AC diesel generators, an electrical distribution system, and distributed AC loads. A hybrid system could also include additional power sources such as renewables (wind turbines, photovoltaic panels) and storage. Note that storage is actually both a source and a load.

Larger systems, nominally above 100 kW, typically consist of AC-connected diesel generators, renewable sources, loads, and occasionally include energy storage subsystems. Below 100 kW, combinations of both AC and DC-connected components are common as is use of energy storage. The DC components could include diesel generators, renewable sources, and storage. Small hybrid systems serving only DC loads, typically less than 5 kW, have been used commercially for many years at remote sites for telecommunications repeater stations and other low power applications.

In general, a hybrid system might contain AC diesel generators, DC diesel generators, an AC distribution system, a DC distribution system, loads, renewable power sources (wind turbines, or photovoltaic power sources), energy storage, power converters, rotary converters, coupled diesel systems, dump loads, load management options, or a supervisory control system. Hybrid systems might also include biomass or hydroelectric generators. A schematic of the possibilities for hybrid systems is illustrated in the following figure. The operation of each of these components and the interactions between them are described in the developed DL course.