Introduction: PV and genset systems do not have much in common. It is precisely for this reason that they can be mated to form a hybrid system that goes far in overcoming the drawbacks to each technology. Table 10.1 lists the respective advantages and disadvantages. As the sun is a variable energy source, PV system designs are increased in size (and therefore cost) to allow for a degree of system autonomy. Autonomy is required to allow for provision of reliable power during "worst case" situations, which are usually periods of adverse weather, seasonally low solar insulation values or an unpredicted increased demand for power. The addition of autonomy to the system is accomplished by increasing the size of the PV array and its requisite energy storage system (the battery). When a genset is added, additional battery charging and direct AC load supply capabilities are provided. The need to build in system autonomy is therefore greatly reduced. When energy demands cannot b