Generating electricity from solar modules is possible either with a stand-alone system (not connected to the utility grid) or with a grid-tied system. Stand-alone systems usually include a means for storing the solar-generated electricity (e.g. batteries). They are useful in an emergency situation when the grid goes down, or for powering small loads, such as a home office, a tool shed, or remote lighting. These systems often have just one or a few modules.
Grid-tied systems are generally larger, perhaps 20 modules or more, and can power an entire house or even a commercial building. These systems are capable of supplying excess electricity to the grid (for credit) when the solar resource exceeds the local demand and also of drawing electricity from the grid when the demand exceeds the solar resource (e.g., at night). Grid-tied systems essentially use the gird for energy "storage" and so usually do not have separate storage devices.
Lightdrop Harvest is capable of designing and implementing both types of systems. Descriptions of two stand-alone systems are available here as examples - one to power a home office (Model LDH-1000) and another to illuminate a highway billboard using LED floodlights (Model LDH-SL4).